Science Majored Students Life At Queens College - 885 Words

Science Majored Students’ Life at Queens College Anthropology is a combination of the words â€Å"Anthropos† and â€Å"Logos†. It simply means the study of human. Since the human beings have both biological and cultural characteristics, anthropology extensively studies including both aspects. However, culture is the most important thing in anthropology. The culture of a particular organization, group, or country consists of the habits of the people in it and the way they generally behave. The particular traits and characteristics are held in common within that environment and are passed on generationally. Based on the culture of the community, group, or country, we can deeply research and understand their life style. The best method that is used†¦show more content†¦The atmosphere was more silent than downstairs. However, unlike the upstairs, the downstairs students looked more freely talked with their friends and received help from them when they were s tuck on particular problems. In the Remsen hall, I observed students in my lecture and lab class. Since the lecture is a huge class, many students tried to sit beside their friends. However, the students who sat by themselves tended to have seats in row at the back of the classroom. After the class started, a lot of students typed the important thing on the slides by their laptop. Some of them took pictures of the slides using their phone. In the lab class, students tended to have more interaction with each other even though the experiment was conducted separately since the class is much smaller than the lecture. They easily talked to other students about the experiment and moreover they tried to help each other to complete the lab procedure correctly. After the lab class, I also looked around the chemistry office. There was a person who came to declare her major and another person who submitted the late lab report. During this observation, I saw a person who took a picture of the b ook in the library. Therefore, I interviewed her after she took all the pictures. Her name is Z.H and she is majoring in sociology and at the particular moment, she took pictures of the book that is used her class. She said she needs to answer the questions based on the readingsShow MoreRelatedEssay on Are Colleges Worth the Price of Admission?4197 Words   |  17 Pagesseveral years, there has been a growing trend in the number of college-bound individuals getting two-year degrees from community colleges or earning certification for their desired career field at vocational schools. Such schools certainly seem to have some valuable qualities: all boast of having lower costs than other colleges, of their absence of student loans, of allowing people to make more money quicker, of being narrowly focused so students don’t have to take classes they don’t need. They attemptRead MoreStatement of Purpose23848 Words   |  96 Pages........................................... ...................................................... 5 Sample Statements of Purpose ........................................................................................................ 8 I. Social Sciences ........................................................................................................................ 8 Education: Teaching English as a Second or Other Language (TESOL)—non-native English Speaker .............................Read MoreInnovators Dna84615 Words   |  339 Pageswinter 1991). â€Å"Most of the attempts to distinguish between entrepreneurs and small business owners or managers have discovered no differentiating features† (R. H. Brockhaus and P. S. Horwitz, â€Å"The Psychology of the Entrepreneur† in The Art and Science of Entrepreneurship, 1986). Solution) to develop a methodology for determining what percentage of a ï ¬ rm’s market value could be attributed to its existing businesses (products, services, markets). If the ï ¬ rm’s market value was higher than theRead MoreMarketing Mistakes and Successes175322 Words   |  702 Pageswould be so enduring? Many of you are past users, a few even for decades. I hope you will find this new edition a worthy successor to earlier editions. I think this may even be my best book. The new Google and Starbucks cases should arouse keen student interest, and may even inspire another generation of entrepreneurs. A fair number of the older cases have faced significant changes in the last few years, for better or for worse, and these we have captured to add to learning insights. After so

Why is Frankenstein such a popular text Essay - 1867 Words

Why is Frankenstein such a popular text? Frankenstein is a science fiction novel written by Mary Shelley during the time of the Romantic Movement. It has remained popular ever since it was first published and still sells well today, with many reprints of the book since the first edition. One of the main characters of the story and probably the most (in)famous, Frankensteins monster, has become an icon of all that is monstrous and wrong. The story has been adapted and interpreted many times all in different ways, causing the monster and the stereotypical view of him to become intertextual. The most popular and well recognised representation of the monster and the one that most people would attempt to draw for you if you†¦show more content†¦Frankenstein is popular for a number of reasons. The most prominent I believe is the fact that it was the first type of story of its kind, and what is now referred to as sci-fi, short for science fiction. Some people also claim it to be a horror novel, due to the monster and his hideous creation, but it is generally classified as science fiction. Science fiction works are based loosely on actual scientific principals and discoveries. For example, Mary Shelley had seen experiments where electricity was passed through dead creatures and they twitched slightly. This was the starting point of Frankenstein and the first time a text of this nature had been written. It single-handedly created a whole new genre for writers to discover. She wrote the story as the result of a challenge that was set to her, her husband and a group of their friends. The challenge was to write the most terrifying story that they could, and the scariest would be the winner. The story predicts the future uses of mans ever growing scientific knowledge, to further preserve life and, in the most extreme cases, actually create new life artificially. It tells the tale of Frankensteins experiments and his eventual success in creating a new human man from the body parts of other dead people. The new human, however, becomes a monster, killing the innocent in his search forShow MoreRelatedFrankendoodle And Frankenstein1079 Words   |  5 PagesFrankenstein is a classic science fiction novel written by Mary Shelley, through the ages, many adaptations have taken the story through various forms of popular culture. SpongeBob Squarepants, a popular children s television show often alludes to classic literature, and makes it entertaining for all ages. While this example is quite comical, it does hold classical elements associated with Frankenstein, but takes a spin on the classic science fiction novel. In this essay I will consider the similaritiesRead MoreA Comparison Of Frankendoodle And Frankenstein1199 Words   |  5 Pagesâ€Å"Frankendoodle† in Comparison to the Original text â€Å"Frankenstein† Frankenstein is a classic science fiction novel written by Mary Shelley, through the ages, many adaptations have taken the story through various forms of popular culture. SpongeBob Squarepants, a popular children s television show often alludes to classic literature, and makes it entertaining for all ages. While this example is quite comical, it does hold classical elements associated with Frankenstein, but takes a spin on the classic scienceRead MoreThemes Of Alienation In Frankenstein1294 Words   |  6 PagesThrough Frankenstein by Mary Shelley as well as Skim by Mariko Tamaki and Jillian Tamaki, themes of alienation are projected throughout both texts. Frankenstein in comparison to Skim is one that must look over the different mediums used to portray ideas , furthermore, it is important to focus on the themes of exclusion and alienation present within both texts. In this essay, I will discuss themes of alienation throughout the two texts Skim, as well as Frankenstein with the c onsideration of: PetscheRead MoreShellys Frankenstein and Miltons Paradise Lost Essay1136 Words   |  5 Pages Mary Shellys Frankenstein narrates a story about a scientist, Victor Frankenstein, and his creation of a monster set apart from all worldly creatures. Frankensteins creation parallels Miltons Paradise Lost and Gods creation of man; Victor Frankenstein is symbolic of God and the monster is symbolic of Adam. The parallel emphasizes the moral limitations of mankind through Victor Frankenstein and the disjunction and correlation with Paradise Lost. Shelly links the two stories together throughRead MoreThe Representation Of The Monster1480 Words   |  6 PagesFrom time to time popular literature has made it’s way to the bring screen every now and again. Once the mass appeal from the text surfaces, these film industry companies to take them into their own hands, which usually altering the integrity of the text. Once specific example that can be found interesting is th e representation of the monster in Frankenstein. In this text the exploration of why director, James Whale, had altered the appearance of the monster not only in the visual aspect, but alsoRead MoreThe Representation Of The Monster1515 Words   |  7 PagesBook vs. Movie From time to time popular literature has made it’s way to the bring screen every now and again. Once the mass appeal from the text surfaces, these film industry companies to take them into their own hands, which usually altering the integrity of the text. Once specific example that can be found interesting is the representation of the monster in Frankenstein. In this text the exploration of why director, James Whale, had altered the appearance of the monster not only in the visualRead MoreSimilar Ideas Presented in Blade Runner by Ridley Scott and Frankenstein by Mary Shelley 1469 Words   |  6 PagesBound by different contexts, authors often use a popular medium in order to depict the discontent of the ideas of society. This is evident in the module Texts in Time; as Blade Runner, having been written more than one hundred years after Frankenstein is still able to reflect the ideas proposed in the latter. Blade Runner by Ridley Scott deals with the effects of globalisation and consumerism during 1980’s. Alternatively, the epistolary novel Frankenstein by Mary Shelley deals with the kinship to theRead MoreValues of Hamlet in comparison to Hamlet movie (2000)2312 Words   |  10 PagesShakespeares famous revenge tragedy Hamlet is a story of unrelenting twists and thrills of madness and revenge. I have chosen to compare this play to Michael Almereydas film made in 2000 that is a modern interpretation of the original text and was an attempt to do to Hamlet what Baz Luhrman did to Romeo and Juliet. This a brief synopsis of the play; Hamlet is the son of King Hamlet who died before the play begins. King Hamlets brother, Claudius takes the throne and marries his wife. The storyRead MoreThe Duality of Man: Connections Between Victor and the Monster in Frankenstein1631 Words   |  7 Pages The classic gothic novel Frankenstein by Mary Shelley details the relationship between two significant figures, Victor Frankenstein, and his unnamed monster. The critical relationship between such characters causes many literary critics to compose the idea that they are bound by nature – inadvertently becoming a single central figure (Spark). This provides provoking thoughts on the duality of mankind, revealing the wickedness of human nature. The role of the monster as an alter ego to Victor isRead MoreFrankenstein and Blade Runner Essay (Contexts and Representation)1792 Words   |  8 PagesExplore the way in which different contexts affects the representation of similar content in the texts Frankenstein and Blade Runner. Mary Shelley’s Frankenstein and Ridley Scott’s Blade Runner, whilst separated by 174 years, feature very similar content which can be seen by comparing the two side by side. Coming from different contexts, they both express their anxieties about technology, which is shown through a man made creature, and they both exhibit a strong valuing of nature. However due

Mobile Phone and Phoebe Cook Copeland Free Essays

Phoebe Cook Copeland ENC0025 8 April 2013 Causes and Effects of texting while driving It is a beautiful Friday morning, when all of a sudden a huge crash is heard in the distance. At the scene of the accident there is a car crushed up against a telephone pole with a young girl inside all bloodied and cut up. Taking a closer look, the young girl seems like she is simply asleep, but in her hand she holds her phone with half written message on the screen saying, â€Å"I’ll be there†¦Ã¢â‚¬  Unfortunately, the young girl never had the chance to finish her text message because she hit a telephone pole. We will write a custom essay sample on Mobile Phone and Phoebe Cook Copeland or any similar topic only for you Order Now This young girl’s life was tragically taken from her; however, this accident could have been avoided if she would have only waited until she got to either her destination or a red light to answer the text message. Sending text messages while driving distracts a person’s attention from the main task, which is driving the vehicle safely. Text messaging is known to contribute to deadly accidents that have prompted several legal districts to ban the practice in many states. The reason that people text while driving in unknown and difficult to pinpoint a specific reason; unfortunately, the effects are clearly visible on the roads and also in the news. The causes and effects of texting while driving can be avoided if people just decided to put the phone down and wait until they are not driving. Texting while driving is very dangerous, but people of all ages still do it. Studies have stated that half of the percent of people of all ages text while driving, and the other half of the percent talk on the phone when behind the wheel. Even though there is no evidence that a person is openly pressured into texting while driving, there is an expectation in society to have the dire need to respond to a text message. However, it is more likely for a person to be involved in a serious accident when texting rather than talking on the phone while driving. The reason behind this is that, when talking on the phone it only distracts the driver, but when texting the driver has to look down at the phone to answer it. Thus, making it not only a distraction for the driver, but they have to take their eyes off the road in order to reply to the message. The effects of texting while driving left a devastating trail that lead to legal implications. Due to having so many accidents on the road, different states passed a law that banned texting while driving. This ban was placed in hopes to lessen the accidents that are caused by people who text and drive. If states can ban driving under the influence, then they can surely ban the no text law in order to keep the roads safer. However, many people have argued that it is hard to spot a person texting while they are driving because they are holding the phone in their laps, which is below the dashboard. So how can the cops catch people who text and drive? The cops are trained to watch for the driver’s body language. If the driver seems like they are texting while behind the wheel the cop is allowed to pull them over and issue them a fine. The causes of texting while driving resolves in the most dangerous effects that ends up taking someone’s life. However, not everyone who gets into an accident while texting is unfortunate, but the most serious accidents are due to people taking their eyes and concentration off the road to answer their text message. The reason why people do not take texting while driving seriously is because they think that taking their eyes off the road for a few seconds would not do any harm. Unfortunately, they are sorely mistaken because it only takes a split second in order for something to go terribly wrong. Not only is it dangerous for the person who is driving, but also for the other people that are in the car and on the road. If people just took texting while driving seriously and understood that it is just as dangerous as anything else, then we would have less accidents and less of people’s lives being tragically stripped from them. In conclusion, it is not the lack of knowledge that people text while driving, but the lack of responsibility that goes into the act. People of all ages know the consequences of texting while driving lead to fatal accidents, yet they still do it. The temptation is too grandeur, however, the person who sent that text message can wait. Not waiting to answer that message while driving will not be worth it in the long run. The causes and effects of texting while driving can be avoided if we choose to put the phone down and wait to answer the text message until we are not driving because answering a text message is never worth a human life. How to cite Mobile Phone and Phoebe Cook Copeland, Papers

My Medical Statement Of Purpose Essay Example For Students

My Medical Statement Of Purpose Essay My name is . I am an African descent and a Nigerian in particular. I am a social person. I am someone with great aspirations and also am I caring by nature. I derive joy from putting smiles on the faces of people. This is because I have a very humane spirit. If one were to ask my friends to describe me, they would portray me as a very kind, pleasant, diverse, active and intelligent young man. I think one of my most distinguishing characteristics is the diversity of knowledge that I possess. I am a science student. And I am a young man with scientific aptitude and an interest in medicine. I also have a passion for traveling and understanding different cultures of the world. All these elements have given me a very broad outlook, with varying certificates and awards of knowledge in a range of topics. I strongly believe that although some are not related directly to my intended field of study, but I suppose that all these qualities will influence my medical work at the University of Tartu. My purpose to study medicine in Tartu is quite a simple one. This is because it is a city of vast educational and cultural diversity. As I said earlier on, I love understanding different cultures of the world. And Tartu in particular is an important industrial and cultural center. Manufactures include footwear, agricultural machinery, printed materials, and lumber. The University of Tartu has been into existence for centuries now and has witnessed both past and present, intellectuals of great timber and caliber. Out of ten centers of excellence, six are established at the University. People go into different professions for quite a lot of reasons. Some go in for the money; some go in for the fame and so on and so forth. My first reason why I became interested in medicine is because of the love I have for humanity. There are numerous areas in medicine that require urgent attention; one of them is the fight against disease pathogens that are responsible for millions of deaths. Today, diseases like tuberculosis, malaria and river blindness that scientists once thought they had won the battle against are now staging a comeback. These bacteria and viruses are now resistant to control measures drugs previously used. This poses an enormous threat to the entire world population. For the sake of humanity, I would engage myself with medical research with the aim of coming up with drugs that would fight diseases once and for all. Most pharmaceutical companies charge high prices for their drugs against HIV/AIDS anti-retroviral drugs, thereby excluding third world countries from the benefit of this medical research. My research findings will be made available to everyone at a very low cost; through this, I believe that my findings will benefit mankind. Just as Alfred Nobel said Scientific research shouldnt be for the sake of prosperity but to save humanity. The human race is at the verge of a terrible catastrophe. There is urgent need to help fight these old diseases that one thought had been eradicated, as well as newly evolved strains like Ebola, and HIV/AIDS. The proceeds from the sale of these drugs would be ploughed back into more research for the benefit of mankind. My other impression of medicine occurred when I had a testicular tuction as doctors said. It was a very painful and serious case that repeatedly required the assistance of physicians in dealing with me. My doctors were always there for me, day in day out. The respect that I bestowed upon doctors, and the doctors ability to ease suffering, sparked a desire to one day become a physician myself. This was an ambitious goal for someone coming from a family in which no one had obtained a professional degree. However, my traditional family-oriented culture, emphasizing doing good for others, contributed to this decision to pursue a career in the medical field. Furthermore, my inbuilt individualistic spirit gave me the confidence and opportunity to undertake a challenging medical career.

Sociology of Sport The Bulls vs. the Nets on April 22, 2013

On April 22, 2013, the Brooklyn Nets met the Chicago Bulls during the NBA basketball game in the eastern conference playoff. This was the second game in the series, and the players and the audience focused on the game’s results in order to predict the success in the next games after the win of the Nets in the first game of the series.Advertising We will write a custom essay sample on Sociology of Sport: The Bulls vs. the Nets on April 22, 2013 specifically for you for only $16.05 $11/page Learn More The game was held at the Barclays Center in Brooklyn, New York. The Barclays Center can accommodate more than 18 thousands of spectators. The majority of seats were occupied with the teams’ fans. It is possible to note that the space and environments did not affect the behaviors of players or fans significantly because of rather comfortable conditions of the place. Nevertheless, it is necessary to concentrate on the atmosphere which can be discu ssed as rather tense because of the game’s significance and because of players and audience’s excitement associated with the starting games of the series. The fans of the Nets and the Bulls could be easily differentiated because of wearing the elements of the clothes and symbols with the teams’ main colours. The Nets’ fans represented the majority of the audience because of the specific place of the game to be held. The majority of the audience was the male public in different age categories, including students and middle-aged person. It is possible to assume that the audience included many representatives of the upper middle class with references to the teams’ status. The public wore a lot of symbolic elements of clothing that is why it was rather difficult to state the social status of fans referring to their dress. The Latin Americans and African Americans were presented at the game. The players of the Nets and the Bulls can be compared with the fans in relation to their age and race. Many players of two teams are African Americans in comparison with the racial division among the audience. Moreover, the middle age of players is not above 35 years when the middle age of the male audience can be discussed as above 37-38 years. It is necessary to concentrate on the specifics of the players’ communication during the game. The style of the players’ game was not aggressive, but the tension was observed. It is possible to refer to the reaction of Joakim Noah (the Bulls) to different technical elements of the game in the form of loud screaming and even roar (Joakim Noah’s roar, 2013). The public actively reacted to the behaviors of the players also with screaming. The ‘waves’ of screaming were observed as the reaction to the teams’ successes as well as faults.Advertising Looking for essay on social sciences? Let's see if we can help you! Get your first paper with 15% OFF Learn M ore It was possible to observe the repeated behaviors of the fans when the groups of fans reflected the reactions of the other groups (Yiannakis Melnick, 2001). Any deviant behaviors expressed by fans were observed. However, it is necessary to note the highly competitiveness among the fans in relation to supporting the team with screams and claps. Definite types of ritualistic behaviors were observed when the fans of the same team greeted each other (Delaney, 2009). The special language is characteristic for the players, coaches, and commentators who use a lot of terms to describe the elements of the game. The fans are inclined to share specific knowledge about the results in the series of games, and about the players’ personalities and style of playing. References Delaney, T. (2009). The sociology of sports: An introduction. USA: McFarland. Joakim Noah’s roar. (2013). Web. Yiannakis, A., Melnick, M. (2001). Contemporary issues in sociology of sport. USA: Human Kin etics. This essay on Sociology of Sport: The Bulls vs. the Nets on April 22, 2013 was written and submitted by user Serenity Blevins to help you with your own studies. You are free to use it for research and reference purposes in order to write your own paper; however, you must cite it accordingly. You can donate your paper here.

Getting Personal in Your Personal Statement

Getting Personal in Your Personal Statement In the essay section of many college applications, students are asked to submit a personal statement outlining their specific goals and/or beliefs. Personal statements are important to the college application process because they give admissions board members the opportunity to get to know their perspective students on an intimate level. If you are applying to college this year and are planning to compose a personal essay, I suggest that you read the following information. The key to a successful personal statement is in the details. When you are creating an outline for your personal essay, think carefully about what personal details you think will best enhance your composition overall. Creating the personal essay is your opportunity to distinguish yourself from everyone else who is applying, so dont hesitate to be creative and unique in your approach. Admission board members want to know as much as possible about their applicants so that they can make well informed decisions. Keep this in mind when writing your statement. Dont be afraid to get personal! Although your essay should be well organized and your writing grammatically correct, the overall tone of your personal composition should be intimate. Discuss your points of view passionately, address your personal goals with zeal, and give the admissions board every reason to grant you admission. Unlike technical and/or research papers, personal essays require the author to search within his or herself for the answers. That is why I believe that personal statements are some of the hardest papers to write. Rest assured, however, that with the right approach, and a good amount of time, you will have no trouble perfecting your personal statement.

Final essay Example | Topics and Well Written Essays - 1750 words - 1

Final - Essay Example , the discussion on recollection and death cannot avoid the aspect of immortality, materiality and invisibility, which is discussed in the dialogue of Socrates and his friends. This paper will therefore seek to examine the viability of the claim that all learning is a process of recollection in relation to the other claims made by Socrates that support the notion. The soul must have been in existence long before one is born and therefore before birth the soul has all knowledge, which it had acquired in its previous life. At the time of birth, the soul is forced to take a new body, which is then supposed to be in control of since the body is mortal but the soul is immortal. The body thus relies on the soul, which plays the divine role and acts as a source of authority for guidance in all its endeavors. As a person grows, the soul may start to forget some of the knowledge acquired as the person encounters different situations, which erode some of the information. However, it is worth noting that the information is not fully lost since when a person acquires knowledge either through sight or through other senses the impression of what is being learned will already be in the mind and the soul will reignite the impression. Therefore, a person can only remember that which he already has an impression on.1 The aspect of abstract equality reinforces the idea that all forms of learning are just a mere process of recollection. When human beings acquire any new form of knowledge they usually have to relate it with what they perceive in their minds to be the absolute truth. But where does absolute truth come from since right from the time that a person starts acquiring knowledge he already possess a definition of this absolute. It therefore emerges that a person is born with this knowledge on abstract equality, which implies that the soul must have existed before and thus acquired all such knowledge. The present reasoning thus only refers to the absolute good, justice,

Education as Initiation Assignment Example | Topics and Well Written Essays - 250 words

Education as Initiation - Assignment Example Peters (1965) presents the idea of education as initiation. In his book, he describes the teacher as an initiator of education and the students as aspirants. His work revolves around the process of being initiated into a given tradition whereby the values of this tradition are passed along. In addition, the author elaborates several education criteria depending on nature of students: Firstly, a state of mind that is desirable develops a valuable aspect that must be initiated. Secondly, education implies that one is being brought into the light because he or she possesses the appropriate skill or knowledge in a manner that involves some degree of understanding. Thirdly, education will always involve seeing everything that is happening in a broader perspective. This implies a cognitive awareness that relates to other fields; knowing what and how. From Plato’s point of view, the goal of schooling is simply to enlighten the mind. Induction prepares a learner by providing brief ideas about the covered information in a particular field. In addition, Plato believes that schooling imparts the knowledge of reality to learners. Learners are always taught what is real or rather the things they will face in the major task. For Instance, when an induction is performed for students in a mathematics class, it gives them an outline of the things they should expect during the entire course. This is outline is real as it is a forecast of the entire subject. Lastly, schooling inculcates the relevant values to students. Learners, irrespective of the level or field of study, obtain the societal values. These values are acceptable in the society as they prepare the students for future or rather initiate the learner into his or her place in the society. Therefore, all these are related to the concept of schooling for induction as it prepares the students for what is ahead.

Motivational Effects of Technology in Music Education Essay

Motivational Effects of Technology in Music Education - Essay Example This report stresses that one of the main issues facing music education is the technological gap between the teachers and the real world. This is because most of the teachers are from another generation of learning and hence they did not acquire technological skills and knowledge in their training. In order to avoid this problem, music teachers and curriculum developers should integrate technology in their learning activities. It is important to note that in this context technology is a purveyor of many benefits which have virtually transformed the music world. Therefore, technology inclusion in the school system is not an imposition but rather a necessity. This paper makes a conclusion technology in music education has many benefits ranging from ease of study accruing from repetitive teaching tasks by computers to unlimited availability and accessibility of learning materials. Music as a subject is not very popular as compared to other disciplines such as engineering. There have been attempts by some countries to reform their music curriculum in a bid to appeal to more students . For instance, Scotland has implemented major reforms in its music schools including establishing technologically-enhanced music rooms for their schools . Technology seems to be the only solution to a seemingly unviable field of study . Integrating technology in a formal learning setting is bound to affect the involved parties in various ways . The effects of technology in education have already been studied in other curriculum.

Tolerability and Haemodynamic Effects of NMES

Tolerability and Haemodynamic Effects of NMES Tolerability and haemodynamic effects of NMES in young healthy individuals Quinn C1, Cooke J1, Deegan B2, Breen P2, Hannigan A3, Dunne C3, Lyons G2 and Lyons D1. Introduction: Discomfort has been identified as a limiting factor for the use of surface NMES. Early implementation of NMES devices were so uncomfortable that they could only be used when the patient was under anaesthetic1. Furthermore, poor quality electrodes combined with monophasic waveforms often resulted in skin irritation and burns. Pambianco et al had to discontinue the NMES portion of the effects of heparin, intermittent pneumatic compression and NMES on DVT rates in stroke rehabilitation patients due to discomfort and skin blister formtion2. More recently the inclusion of microcontrollers in the design of NMES devices has allowed the implementation of precisely controlled waveforms and novel algorithms3. These waveforms and algorithms have significantly increased the comfort and tolerance of NMES users. Moreover the use of biphasic pulses, either asymmetric or symmetric has minimised ion redistribution and the subsequent risk of skin irritation and burns. Previous studies have examined patient perceptions of NMES. Alon et al. examined the effect of 4 different electrode sizes on excitatory responses (sensory, motor, pain and pain tolerance) on healthy participants and concluded that NMES comfort increases with increase in electrode size4. They also observed that increasing electrode size decreases the peak voltage corresponding to the excitatory levels. Clarke-Moloney et al assessed the comfort associated with and without NMES on patients with chronic venous insufficiency using a visual analogue scale (VAS)5. The authors found that the comfort categorical rating remained unchanged in all but one patient. This indicated that patients found NMES to be an acceptable therapy which could be significant in future studies involving NMES treatments for venous wound healing. Broderick et al. previously conducted a study involving healthy participants who underwent a 4 hour stimulation protocol6. Three participants indicated moderate discomfort and 7 only mild discomfort when NMES was commenced. By the end of the study, 2 participant’s scores increased to moderate while 2 other participant’s scores decreased to mild the remainder were unchanged. Kaplan et al. asked each healthy participant who received NMES of the calf or foot muscles to complete a questionnaire regarding the acceptance of NMES. Both groups found NMES to be comfortable and strongly felt they would use the NMES device if directed by their doctor7. More recently a study by Corley et al. demonstrated the use of a week-long NMES blood flow protocol in conjunction with compression stockings resulted in a high level of compliance and no reported adverse effects8. Our pilot study concluded that NMES may be useful in attenuating blood pressure drops in older subjects with OH. The asynchronous NMES setting demonstrated the most favourable haemodynamic response. The aims of this study were to assess tolerance and acceptability of both synchronous and asynchronous NMES settings in a young, healthy population during head-up tilt testing. A secondary objective was to assess the effect of both settings on haemodynamic parameters in this group. Methods: Subjects Healthy subjects (n=14) were recruited. Ten were male. The subjects’ medical history did not reveal any episodes of vasovagal syncope, cardiovascular diseases or any other morbidity. None of the subjects used any medication, and all subjects were non-smokers. Ethical Approval Ethical approval for this study was granted by University Hospital Limerick Research Ethics Committee. All subjects gave written consent to take part in the study. Tilt Protocol Subjects were asked to fast for a maximum of two hours beforehand. Studies were performed in a quiet syncope syncope laboratory room at ambient temperature (21-23 C). The tilt protocol was completed between 9am and 5pm. The study protocol included 3 Head-Up-Tilts (HUT) comprising asynchronous, synchronous settings and control. The order of each intervention was randomly assigned using closed envelope randomisation technique. HUT testing was performed using standardised conditions in accordance with the 1996 expert consensus document for all patients9. Subjects were required to rest in the supine position for five minutes prior to the onset of a 70 degree positive tilt. This was sustained for three minutes as per European Society of Cardiology guidelines10. Haemodynamic changes were recorded using non-invasive beat-to-beat digital artery photoplethysmography Finometer ® Pro Device (Finapres Medical Systems BV, Amsterdam, The Netherlands www.finapres.com). Continuous cardiac monitoring was performed with three lead ECG (figure 2). OH was defined as a drop in systolic blood pressure of ≠¥ 20mmHg or in diastolic blood pressure of ≠¥ 10mmHg within three minutes of orthostasis10. The delta (or change) in systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), mean arterial pressure (MAP), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were rec orded in each subject at baseline and at the lowest point (nadir) for each HUT. Electrical stimulation protocol NMES was applied a custom built, two channel stimulator (Duo-STIM, Bioelectrics Research Cluster, NUI Galway)11. NMES was facilitated through the use of two 5 cmÃâ€"5 cm PALS self-adhesive, hypo-allergenic, skin surface electrodes (Nidd Valley Medical Limited, England) placed over the motor points of the soleus muscles of both legs of consenting patients12 (Figure 3). The stimulator was programmed to provide a pulse width of 350  µs, an inter-pulse interval of 100  µs, a frequency of 36 Hz, a contraction time of 1.2 second, a ramp up time of 500 ms and ramp down time of 300ms. This yielded stimulation amplitudes of 29.18  ± 4.2 V11. The stimulation parameters were selected at a level to achieve maximum blood flow while ensuring subject comfort. A series of test pulses were applied initially at a very low intensity to establish that the patient was comfortable with the sensation of electrical stimulation. The stimulus intensity was gradually increased until a noticeable contrac tion was observed for both legs, as indicated by a visible tightening of the soleus muscle or slight plantar flexion. Stimulation was applied alternatively to each leg with 3 second rest between contractions or synchronously to both legs with 3 second rest period at the onset of each HUT and continued for the three minute study duration. Duplex scanning Duplex Doppler ultrasound was used to monitor the subjects’ lower limb venous hemodynamic responses using a Siemens Sonoline Sienna ultrasound machine with a broadband array probe (Frequency 5 – 13 MHz). All measurements were performed by a single examiner. Blood flow measurements were taken from the popliteal vein at the lateral aspect of the knee (Fig. 1). Doppler ultrasound with angle correction not exceeding 600 was used and matched to the diameter of the popliteal vein. All measurements were taken from the right leg. Three measurements were taken per parameter and the average of these was used for analyses5, 13. Peak venous velocity was recorded from the popliteal vein. The Doppler machine’s own software was used to calculate venous volume flow (ml/min) by multiplying the average blood flow velocity by the cross-sectional area of the popliteal vein. Doppler measurements were taken at baseline and on assumption of the upright stance. Figure 1: Placement of ultrasound probe in popliteal fossa Figure 2: Screen shot of output from ultrasound software demonstrating venous blood flow and peak systolic velocity Comfort evaluation procedure At 2 time points (just after set-up of the NMES and at the end of the protocol), comfort was assessed by asking subjects to mark their level of comfort using a 100 mm, non-hatched visual-analogue scale (VAS). A VAS of 30 mm or less was categorised as mild pain, between 31 and 69 mm as moderate pain and scores of 70 mm or greater as severe pain. The minimum clinical significant difference (MCSD) in VAS was set as an increase in scores between test stages of 12mm14. At the end of the study, the patients were asked to complete a short verbal questionnaire. They were asked: To give a verbal categorical rating of the NMES treatment as very comfortable, comfortable, bearable or unbearable. To clarify preferred stimulation pattern. If they would consider NMES an acceptable form of treatment. Symptom recording Each subject was asked to mark the degree of symptoms encountered during the HUT using a 100 mm, non-hatched visual-analogue scale (VAS) once the tilt table had returned to the horizontal position. Statistical analysis Results: Discussion: Conclusion: Outcomes for tolerability study 1: Tolerability: Pain – pre and post change NMES sensation Acceptability Preference Symptoms 2: Haemodynamic parameters for each intervention: Delta SBP, DBP, HR, MAP, SV, CO TPR Peak systolic velocity Venous flow 3: Associations of presence of initial OH References: Browse NL, Negus D. Prevention of postoperative leg vein thrombosis by electrical muscle stimulation. An evaluation with 125 I-labelled fibrinogen. Br Med J 1970;3:615-618. Pambianco G, Orchard T, Landau P. Deep vein thrombosis: prevention in stroke patients during rehabilitation. Arch Phys Med Rehabil 1995;76:324-330. Broderick B, Breen P, OLaighain G, Eelectrical stimulators for surface neural prosthesis. J Autom Control 2008;18:25-33. Alon G, Kantor G, Ho HS. Effects of electrode size on basic excitatory responses and on selected stimulus parameters. J Orthop Sports Phys Ther 1994;20:29-35. Clarke-Moloney M, Lyons GM, Breen P, Burke PE, Grace PA. Haemodynamic study examining the response of venous blood flow to electrical stimulation of the gastrocnemius muscle in patients with chronic venous disease. Eur J Vasc Endovasc Surg 2005;31:300-305. Broderick BJ, O’Brien DE, Breen PP, Kearns SR, OLaighin G. A pilot evaluation of a neuromuscular electrical stimulation (NMES) based methodology for the prevention of venous stasis during bed rest. Med Eng Phys 2010;32:349-355. Kaplan RE, Czyrny JJ, Fung TS, Unsworth JD, Hirsh J. Electrical foot stimulation and implications for the prevention of venous thromboembolic disease. Thromb Haemost 2002;10:35-45. Corley CJ, Breen PP, Birlea S, Serrador JM, Grace PA, OLaighin G. Hemodynamic effects of habituation to a week-long program of neuromuscular electrical stimulation. Med Eng Phys 2012;34:459-456. Benditt DG, Ferguson DW, Grubb BP, et al. Tilt table testing for assessing syncope. American College of Cardiology. J Am Coll Cardiol. 1996;28: 263-275. Brignole M, Alboni P, Benditt DG, et al. Guidelines on management (diagnosis and treatment) of syncope-update 2004. Executive Summary. Eur Heart J. 2004;25: 2054-2072. Breen PP, Corley CJ, O’Keeffe DT, Conway R, OLaighin G. A programmable and portable NMES device for foot drop correction and blood flow assist applications. Med Eng Phys 2009;31:400-4008. Baker LL, McNeal DR, Benton LA, Bowman BR, Waters RL. Neuromuscular Electrical Stimulation – A practical Guide. 3rd ed. Downey, California: Rancho Llos Amigos Research and Education Institute; 1993. Izumi M, Ikeuchi M, Mitani T, Taniguchi S, Tani T. Prevention of venous stasis in the lower limb by transcutaneous electrical nerve stimulation. Eur J Vasc Endovasc Surg 2010;39:642-645. Kelly AM. The minimum clinically significant difference in visual analogue scale pain score does not differ with severity of pain. Emerg Med J 2001;18:205-207.

Cry, the Beloved Country: Change :: Cry the Beloved Country Essays

In undertaking a journey, a person learns and changes. One may change emotionally, psychologically, as well as spiritually. The journeyer is scared at first, then usually goes through some pain and suffering. In the end, however, this journeyer comes out different then they were when they began, with some understanding. Stephan Kumalo, James Jarvis, and Absalom Kumalo undertake this very thing in Cry, the Beloved Country, by Alan Paton. Stephan Kumalo, a priest from the small native town of Ndotsheni, takes a journey to the great city of Johannesburg. He intends to find his sick sister and his son, Absalom, who has gone away. At first, Stephan has "the fear of the unknown, the fear of the great city"(44) where his loved ones had gone to and not written in months. Not long after he begins, he realizes "this is a bitter journey"(55) upon hearing the occupations and practices of his sister. He goes through pain and suffering, more and more as he learns of his brother's loss of faith in the church, and the murder his son has committed. But, soon enough he comes to an understanding of this world in Johannesburg. He learns why there is so much crime and poverty. He then has hope the success of his daughter in-law and his nephew in Ndotsheni. He gains hope for the rebuilding of the tribe. Stephan Kumalo comes away from his journey changing spiritually and knowing that there is "comfort in a world of desolation"(94). He changes emotionally and becomes stronger. Also, he changes psychologically and learning the troubles of Johannesburg and apartheid, and their various causes. James Jarvis undergoes vast changes during his journey. He is told that his son has been killed, and he leaves for Johannesburg at once. His son, Arthur, was a social activist helping natives in South Africa, trying to get better hospitals and schools for them. These are subjects James Jarvis never thought about much. When he arrives at his son's house, the place of Arthur's death, he reads through some of his manuscripts and books. First, James suffers a lot thinking about his son's death. As he reads through some of his books and papers however, he comes to an understanding how great a man his son was, and what he stood for. "He sat smoking his pipe and was lost in thought"(180) after he reads a manuscript on what is permissible and what is not

Sci 241 Week 5

( ©Reinhard/Age Fotostock America, Inc. ) CHAPTER 8 CONCEPTS I I I I I I I I I Thiamin, ribo? avin, niacin, biotin, and pantothenic acid are B vitamins needed to produce ATP from carbohydrate, fat, and protein. Vitamin B6 is important for amino acid metabolism as well as energy production. Folate is a coenzyme that is needed for cell division. Vitamin B12, only found in animal foods, is needed for nerve function and to activate folate. Vitamin C is needed to form connective tissue and acts as a watersoluble antioxidant. Vitamin A is essential for vision, and it regulates cell differentiation and growth. Vitamin D is necessary for bone health. Vitamin E is a fat-soluble antioxidant. Vitamin K is essential for blood clotting. u s t A Ta s t e J Do vitamins give you extra energy? Should everyone take folate supplements? Does eating carrots improve your vision? Can vitamin E protect you from heart disease? The Vitamins Vitamins Are Vital to Your Health Vitamins Provide Many Different Functions in the Body Vitamins Are Found in Almost Everything You Eat We Need Enough but Not Too Much of Each Vitamin Some Vitamins Are Soluble in Water and Others Are Soluble in Fat Many B Vitamins Are Essential for Energy Production Thiamin: Important for Nerve Function Ribo? vin: A Bright Yellow Vitamin Niacin: De? ciency Caused an Epidemic of Mental Illness Biotin: Eggs Contain It but Can Block Its Use Pantothenic Acid: Widely Distributed in Food and Widely Used in the Body Vitamin B6 Is Important for Protein Metabolism Vitamin B6 Is Needed to Synthesize and Break Down Amino Acids Both Animal and Plant Foods Are Good Sources of Vitamin B6 Too Much Vitamin B6 Is Toxic Folate and Vitamin B12 Are Needed for Cell Division Folate: Important for Rapidly Dividing Cells Vitamin B12: Absorption Requires Intrinsic Factor Vitamin C Saved Sailors from Scurvy Vitamin C Is Needed to Maintain Connective Tissue Vitamin C Is a Water-Soluble Antioxidant Citrus Fruit Is One of the Best Sources of Vitamin C Vitamin C Is the Most Common Vitamin Supplement Choline: Is It a Vitamin? Vitamin A Is Needed for Healthy Eyes Vitamin A Comes in Preformed and Precursor Forms Vitamin A Requires Fat for Absorption and Protein for Transport Vitamin A Is Necessary for Vision Vitamin A Regulates Gene Expression -Carotene Is a Vitamin A Precursor and an Antioxidant Vitamin A Needs Can Be Met with Plant and Animal Sources Vitamin A De? iency Is a World Health Problem Preformed Vitamin A Can Be Toxic Vitamin D Can Be Made in the Skin Vitamin D Is Needed to Maintain Normal Calcium Levels Vitamin D De? ciency Causes Weak Bones Only a Few Foods Are Natural Sources of Vitamin D Too Much Vitamin D Causes Calcium to Deposit in the Wrong Tissues Vitamin E Protects Membranes Vitamin E Is a Fat-Soluble Antioxidant Vitamin E De? ciency Damages Membranes Most of the Vitamin E in Our Diets Comes fr om Plant Oils Vitamin E Is Relatively Nontoxic Vitamin K Is Needed for Blood Clotting Vitamin K De? iency Causes Bleeding Drugs That Inhibit Vitamin K Prevent Fatal Blood Clots The Requirement for Vitamin K Is Met by Bacterial Synthesis and Food Sources 8 INTRODUCTION Vitamin D Concerns on the Rise By Karen Collins, R. D. Dec. 5, 2003—A lack of vitamin D—thought to be a problem of a bygone era—is showing up in growing numbers of women, children, and the elderly, increasing the risk of bone disease and possibly other health problems. Exposing only the face, hands, and forearms to sunlight for 10 to 30 minutes, just two or three days a week, can usually produce all the vitamin D we need. Longer exposure doesn’t produce more of this vitamin. Yet today, many people’s lifestyles and locations do not allow them to produce enough, making dietary sources vital. For more information on vitamin D concerns go to www. msnbc. msn. com/id/3660416. A ren’t vitamin de? ciency diseases a thing of the past? After all, the vitamins have been identi? ed, characterized, and puri? ed. We get them from foods that are natural sources and they are added to our breakfast cereal and sold in pill form. For over 100 years scientists have been experimenting with how much of which ones we need to stay healthy and public health of? ials have been providing us with guidelines as to how best to get enough from our diets. How can anyone have a de? ciency? Despite advances in vitamin research over the last century, millions of people around the globe still suffer from vitamin de? ciency diseases. In the United States, the plentiful and 235 236 Chapter 8 The Vitamins varied food s upply make severe vitamin de? ciencies unlikely but this doesn’t mean everyone gets enough of everything all the time. Marginal de? ciencies often go unnoticed and can be mistaken for other conditions. Vitamins Are Vital to Your Health L Vitamins Organic compounds needed * in the diet in small amounts to promote and regulate the chemical reactions and processes needed for growth, reproduction, and the maintenance of health. Vitamins are essential to your health. You only need very small quantities but if you don’t get enough your body cannot function optimally. Severe de? ciencies cause debilitating diseases but even marginal intakes can cause subtle changes that affect your health today and your risk of chronic disease tomorrow. An organic substance is classi? ed as a vitamin if lack of it in the diet causes symptoms that are relieved by adding it back to the diet. The fact that the vitamins we eat in food are essential to health seems simple and obvious, but it was not always so. For centuries, people knew that some diseases could be cured by certain foods. But it was a long time before we understood why particular foods relieved speci? c ailments. Cures attributed to foods seemed like nothing short of a miracle. People too weak to rise from their beds, those with bleeding wounds that would not heal, those too mentally disturbed to function in society, and those with other serious ailments were cured with changes in diet. Even before the chemistry of these substances was unraveled, the civilized world was enchanted with the magic of vitamins. They brought hope that incurable diseases could be remedied by simple dietary additions. Today we understand what vitamins do and why they cure de? ciency diseases, but we still hold out hope for more miracles from these small molecules. And we might get a few. Scientists continue to discover important links between vitamins and the risk of developing illnesses such as heart disease, cancer, osteoporosis, and high blood pressure. What is being uncovered is far subtler than the miracle cures of the 19thcentury de? iency diseases, but people cling to the belief that taking more vitamins will cure what ails them. As a result of this â€Å"more is always better† attitude vitamin toxicities have become a concern. A toxic reaction can be as devastating as a de? ciency. Trying to get the right amount of each of the vitamins may sound analogous to walking a tightr ope between not enough and too much. In reality it is not that hard to get enough of most vitamins from a well-planned diet and most toxicities are not caused by foods but rather by excessive use of supplements. Vitamins provide many different functions in the body To date, 13 substances have been identi? ed as vitamins essential in the diet (Table 8. 1). They were named alphabetically in approximately the order in which they were identi? ed: A, B, C, D, and E. The B vitamins were ? rst thought to be one chemical substance but were later found to be many different substances, so the alphabetical name was broken down by numbers. Vitamins B6 and B12 are the only ones that are still commonly referred to by their numbers. Thiamin, ribo? avin, and niacin were originally referred to as vitamin B1, B2, and B3, respectively, but today they are not typically called by these names. Vitamins each have a unique role in the body. For instance, vitamin A is needed for vision, vitamin K is needed for blood clotting, and vitamin C is needed to synthesize connective tissue. Many body processes require the presence of more than one vitamin. For example the B vitamins thiamin, ribo? avin, niacin, biotin, and pantothenic acid are all needed to produce ATP from carbohydrate, fat, and protein. In some cases adequate amounts of one vitamin depend on the presence of another. For example, vitamin B12 is needed to provide the form of folate needed for cell division and vitamin C helps restore vitamin E to its active form. Vitamins Are Vital to Your Health 237 TABLE 8. 1 Where Does Each Vitamin Fit? Water-Soluble Vitamins B Vitamins †¢ Thiamin (B1) †¢ Ribo? avin (B2) †¢ Niacin (B3) †¢ Biotin †¢ Pantothenic acid †¢ Vitamin B6 †¢ Folate †¢ Vitamin B12 Vitamin C Fat-Soluble Vitamins Vitamin A Vitamin D Vitamin E Vitamin K Vitamins are found in almost everything you eat Almost all foods contain some vitamins (Figure 8. 1). Grain products are good sources of the B vitamins thiamin, niacin, ribo? avin, pantothenic acid, and vitamin B6. Meats, such as beef, pork, and chicken, and ? sh are good sources of all of the B vitamins. Milk provides ribo? avin and vitamins A and D; leafy greens, such as spinach and kale, provide folate, vitamin A, vitamin E, and vitamin K; citrus fruits like oranges and grapefruit provide vitamin C; and vegetable oils, such as corn and saf? ower oil, are high in vitamin E. FIGURE 8. 1 All the food groups contain choices that are good sources of vitamins. ( © Topic Photo Agency) (PhotoDisc, Inc. /Getty Images) Processing affects vitamin content The amount of a vitamin in a food depends on the amount naturally found in that food as well as how the food is cooked, stored, and processed. The vitamins naturally found in foods can be washed away during preparation, destroyed by cooking, or damaged by exposure to light or oxygen. Thus, processing steps such as canning vegetables, re? ning grains, and drying fruits can cause nutrient losses. However, other processing steps such as forti? cation and enrichment add nutrients to foods. Some nutrients are added to foods to prevent vitamin or mineral de? ciencies and promote health in the population (see Chapter 10). For example, milk is forti? ed with vitamin D to promote bone health, and grains are forti? ed with folic acid to reduce the incidence of birth defects. Some foods are also forti? ed with nutrients to help increase product sales. Dietary supplements can boost vitamin intake We also get vitamins in dietary supplements. Currently about half of adult Americans take some form of dietary supplement on a daily basis and 80% take them occasionally. 1 While supplements provide speci? c nutrients, they do not provide all the bene? ts of foods. A pill that meets vitamin needs does not provide the energy, protein, minerals, ? ber, or phytochemicals that would have been supplied by food sources of these vitamins (see Chapter 10). Not all of what you eat can be used by the body The vitamins that we consume in our diets are needed in the cells and ? uids of our body. In order to provide their essential functions, vitamins must get to the target tissues. The amount of a nutrient consumed that can be used by the body is referred to as its bioavailability. Bioavailability is affected by the composition of individual foods, the diet as a whole, and conditions in the body. For example, the thiamin in certain individual foods such as blueberries and red cabbage cannot be used by the body because these foods contain antithiamin factors that destroy the thiamin. An example of how L Forti? cation A term used generally to * describe the addition of nutrients to foods, such as the addition of vitamin D to milk. L Enrichment The addition of speci? c * nutrients to a food to restore those lost in processing to a level equal to or higher than originally present. L Dietary supplement A product * intended for ingestion in the diet that contains one or more of the following: vitamins, minerals, plant-derived substances, amino acids, or concentrates or extracts. L Bioavailability A general term that * refers to how well a nutrient can be absorbed and used by the body. 38 Chapter 8 The Vitamins Chewing helps break apart fiber and release vitamins Bile produced by the liver helps to absorb fat-soluble vitamins Digestion in the stomach releases vitamins from food Some niacin absorption Liver Stomach Digestive enzymes released by pancreas help to further release vitamins Fat-soluble vitamins absorbed from micelles along with dietary fat Pancreas Water-sol uble vitamins (thiamin, riboflavin, niacin, vitamin B6, biotin, pantothenic acid) absorbed by simple diffusion, facilitated diffusion, and active transport Vitamin C absorbed in later portion (ileum) of small intestine Small Intestine Vitamin B12 absorbed in later portion (ileum) of small intestine Large Intestine Absorption of small amounts of vitamin K, biotin, and pantothenic acid made by bacteria in the large intestine FIGURE 8. 2 An overview of vitamins in the digestive tract. diet composition affects vitamin bioavailability is dietary fat and the absorption of fatsoluble vitamins. Because fat-soluble vitamins are absorbed along with dietary fat, diets very low in fat reduce absorption (Figure 8. 2). Conditions in the body affect bioavailability in several ways. Some vitamins require speci? c molecules in order to be absorbed. If these aren’t available, the vitamin cannot be absorbed in suf? cient amounts. For example, vitamin B12 must be bound to a protein produced in the stomach before it can be absorbed in the intestine. If this protein is not available, adequate amounts of vitamin B12 cannot be absorbed. Other vitamins require transport molecules to travel in the blood to the tissues that need them. Vitamin A is stored in the liver, but it must be bound to a speci? transport protein to travel in the blood to other tissues; therefore, the amount delivered to the tissues depends on the availability of the transport protein. We need enough but not too much of each vitamin The right amounts and combinations of vitamins and other nutrients are essential to health. Despite our knowledge of what vitamins do and how much of each we need, we don’t all consume the right amounts. In developing countries, vitamin de? ciencies remain a major public health problem. In industrialized countries, a more varied food supply, along with forti? ation, has almost eliminated vitamin-de? ciency diseases in the majority of the population. Concern in these countries now focuses on meeting the needs of high-risk groups such as children and pregnant women, determining the effects of marginal de? ciencies such as the effect of low B vitamin intake on heart disease risk, and evaluating the risk of consuming large amounts. The RDAs and AIs of the Dietary Reference Intakes (DRI) recommend amounts that provide enough of Vitamins Are Vital to Your Health 239 each of the vitamins to prevent a de? ciency and promote health (see Chapter 2). Because more is not always better when it comes to nutrient intake, the DRIs have also established Tolerable Upper Intake Levels (ULs) as a guide to amounts that are high enough to pose a risk of toxicity (see inside cover). Some vitamins are soluble in water and others are soluble in fat We group vitamins based on their solubility in water or fat, a characteristic that affects how they are absorbed, transported, excreted, and stored in the body. The watersoluble vitamins include the B vitamins and vitamin C. The fat-soluble vitamins include vitamins A, D, E, and K (see Table 8. 1) With he exception of vitamin B12, the water-soluble vitamins are easily excreted from the body in the urine. Because they are not stored to any great extent, supplies of most water-soluble vitamins are rapidly depleted and they must be consumed regularly in the diet. Nevertheless, it takes more than a few days to develop de? ciency symptoms, even when these vitamins are completely eliminated from the diet. Fatsoluble vitamins, on the other hand, are stored in the liver and fatty tissues and cannot be excreted in the urine. In general, because they are stored to a larger extent, it takes longer to develop a de? iency of fat-soluble vitamins when they are no longer provided by the diet. In this chapter the water-soluble vitamins are presented ? rst because many play an important role in the reactions that produce energy from carbohydrate, fat, and protein that have been addressed in Chapters 4 through 7 (Table 8. 2). L Water-soluble vitamins Vitamins that * dissolve in water. L Fat-soluble vitamins Vitamins that * dissolve in fat. TABLE 8. 2 A Quick Guide to the Water-Soluble Vitamins Food Sources Pork, whole and enriched grains, seeds, nuts, legumes Recommended Intake for Adults 1. –1. 2 mg/day Major Functions Coenzyme in glucose metabolism, needed for neurotransmitter synthesis and normal nerve function Coenzyme needed in energy metabolism De? ciency Symptoms Berberi: weakness , apathy, irritability, nerve tingling, poor coordination, paralysis, heart changes In? ammation of mouth and tongue, cracks at corners of the mouth Pellagra: diarrhea, dermatitis on areas exposed to sun, dementia Groups at Risk of De? ciency Alcoholics, those living in poverty Toxicity and UL None reported. No UL Vitamin Thiamin (vitamin B1, thiamin mononitrate) Ribo? vin (vitamin B2) Dairy products, 1. 1–1. 3 mg/day whole and enriched grains, leafy green vegetables, meats Beef, chicken, ? sh, peanuts, legumes, whole and enriched grains. Can be made from tryptophan 14–16 mg NE/day None None reported. No UL Niacin (nicotinamide, nicotinic acid, vitamin B3) Coenzyme needed in energy metabolism and lipid synthesis and breakdown Those consuming a limited diet based on corn, alcoholics Flushing, nausea, rash, tingling extremities. UL is 35 mg from forti? ed foods and supplements (Continued) 240 Chapter 8 The Vitamins TABLE 8. 2 (Continued ) Food Sources Liver, egg yolks, synthesized in the gut Recommended Intake for Adults 30 g/day Major Functions De? ciency Symptoms Groups at Risk of De? ciency Those consuming large amounts of raw egg whites, alcoholics None Toxicity and UL None reported. No UL Vitamin Biotin Coenzyme in Dermatitis, glucose production nausea, and lipid synthesis depression, hallucinations Pantothenic acid (calcium pantothenate) Vitamin B6 (pyridoxine, pyridoxal, pyridoxamine) Meat, legumes, whole grains, widespread in foods Meat, ? sh, poultry, legumes, whole grains, nuts and seeds Leafy green vegetables, legumes, seeds, enriched grains 5 mg/day Coenzyme in Fatigue, rash energy metabolism and lipid synthesis and breakdown Coenzyme in protein metabolism, neurotransmitter and hemoglobin synthesis Coenzyme in DNA synthesis and amino acid metabolism Headache, numbness, tingling, convulsions, nausea, poor growth, anemia Macrocytic anemia, in? ammation of tongue, diarrhea, poor growth, neural tube defects Pernicious anemia, macrocytic anemia, nerve damage Scurvy: poor wound healing, bleeding gums, loose teeth, bone fragility, joint pain, pinpoint hemorrhages Liver dysfunction None reported. No UL Numbness, nerve damage. UL is 100 mg 1. 3–1. 7 mg/day Women, alcoholics Folate (folic acid, folacin, pteroyglutamic acid) 400 g DFE/day Pregnant women, alcoholics Masks B12 de? ciency. UL is 1000 g from forti? ed food and supplements None reported. No UL Animal products 2. 4 g/day Vitamin B12 (cobalamin, cyanocobalamin) Coenzyme in folate metabolism, nerve function Vegans, women, those with stomach or intestinal disease Alcoholics, elderly men Vitamin C (ascorbic acid, ascorbate) Citrus fruit, broccoli, strawberries, greens, peppers 75–90 mg/day Collagen (connective tissue) synthesis; hormone and neurotransmitter synthesis, antioxidant Synthesis of cell membranes and neurotransmitters GI distress, diarrhea. UL is 2000 mg Choline* Egg yolks, organ meats, leafy greens, nuts, body synthesis 425–550 mg/day None Sweating low blood pressure, liver damage. UL is 3500 mg UL, Tolerable Upper Intake Level; NE, niacin equivalent; DFE, dietary folate equivalent. *Choline is technically not a vitamin but recommendations have been made for its intake. Many B Vitamins Are Essential for Energy Production 241 Many B Vitamins Are Essential for Energy Production For many people the term vitamin is synonymous with energy. But vitamins do not actually contain any energy at all. We get energy from the carbohydrate, fat, and protein in our diet, but we can’t use the energy contained in these nutrients without the help of vitamins. The B vitamins thiamin, ribo? avin, niacin, pantothenic acid, and biotin are directly involved in converting the energy in carbohydrate, fat, and protein into ATP—the form of energy that is used to run the body (Figure 8. 3). Each of these vitamins acts as a coenzyme in one or more of the chemical reactions necessary to generate usable energy from these nutrients (Figure 8. 4). Thiamin: important for nerve function Thiamin is needed for nerve cells to obtain energy and to synthesize an important neurotransmitter. A de? ciency of thiamin causes beriberi, a condition that has been known for over 1000 years in East Asian countries. In Sri Lanka, the word beriberi literally means â€Å"I cannot†; this phrase refers to the extreme weakness that is the earliest symptom of the condition. Beriberi came to the attention of Western medicine in colonial Asia in the 19th century. It became such a problem that the Dutch East India Company sent a team of scientists to ? nd its cause. What they were expecting to ? d was a germ like those that caused cholera and rabies. What they found for a long time was nothing. For over 10 years, a young physician named Christian Eijkman worked C C C C C C Although people often take B vitamins to get more energy these vitamins do not actually provide energy. They are however necessary for the body to produce energy from other nutrients. L Coenzymes Small nonprotein o rganic * molecules that act as carriers of electrons or atoms in metabolic reactions and are necessary for the proper functioning of many enzymes. L Beriberi The disease resulting from a * de? iency of thiamin. O C C O C C C C C OH C C Glucose Fatty acid Amino acids Niacin Biotin Niacin Riboflavin Biotin Pantothenic acid Niacin Riboflavin Biotin Pantothenic acid O2 Thiamin Riboflavin Niacin Pantothenic acid C C Thiamin Riboflavin Pantothenic acid C C C Niacin Riboflavin H2O CO2 ATP FIGURE 8. 3 Thiamin, ribo? avin, niacin, biotin, and pantothenic acid are needed in the reactions that produce energy from carbohydrate, fat, and protein. If one of these is missing, energy production is disrupted. 242 Chapter 8 The Vitamins Coenzyme Incomplete enzyme Active enzyme A B A B Enzyme reaction FIGURE 8. 4 The B vitamins serve as coenzymes. This ? gure shows that the coenzyme must bind to form an active enzyme. The enzyme in this example can then join A and B to form a new molecule, shown here as AB. AB to ? nd the cause of beriberi. His success came as a twist of fate. He ran out of food for his experimental chickens and instead of the usual brown rice, he fed them white rice. Shortly thereafter, the chickens came down with beriberi-like symptoms. When he fed them brown rice again, they got well. What did this mean? To Eijkman it provided evidence that the cause of beriberi was not a poison or a microorganism, but rather something missing from the chicken feed. The incidence of beriberi in East Asia increased dramatically the 1800s due to the rising popularity of polished rice. Polished or white rice is produced by polishing off the bran layer of brown rice creating a more uniform product. However, polishing off the bran also removes the vitamin-rich portion of the grain (Figure 8. 5). Therefore, in populations where white rice was the staple of the diet, beriberi, became a common health problem. FIGURE 8. 5 Unenriched white rice is a poor source of thiamin. (Charles D. Winters) L Wernicke-Korsakoff syndrome A form * of thiamin de? ciency associated with alcohol abuse that is characterized by mental confusion, disorientation, loss of memory, and a staggering gait. Thiamin is needed to produce energy from glucose The reason thiamin is needed for nerve cells to obtain energy is because it is a coenzyme for some of the important energy-yielding reactions in the body. One of these is essential for the production of energy from glucose, the energy source for nerve cells. In addition to its role in energy production it is needed for neurotransmitter synthesis and is also essential for the metabolism of other sugars and certain amino acids, and for the synthesis of ribose, a sugar that is part of the structure of RNA (ribonucleic acid). Thiamin de? ciency affects the nervous and cardiovascular systems. Without thiamin, glucose, which is the primary fuel for the brain and nerve cells, cannot be used normally and nerve impulses cannot be transmitted normally. This leads to weakness and depression, which are the ? st symptoms of beriberi; other neurological symptoms include poor coordination, tingling sensations, and paralysis. The reason de? ciency affects the cardiovascular system is not well understood, but symptoms include rapid heartbeat and enlargement of the heart. Overt beriberi is rare in North America today, but a form of thiamin de? ciency called Wernicke-Korsakoff syndrome does occur in alcoholics. People with this condition experience mental confusion, psychosis, memory disturbances, and eventually coma. They are particularly vulnerable because thiamin absorption is decreased due to the effect of alcohol on the gastrointestinal tract. In addition, thiamin intake is low because alcohol contributes calories to the alcoholic’s diet but brings with it almost no nutrients. Many B Vitamins Are Essential for Energy Production RDA Sunflower seeds (1/4 c) Walnuts (1/4 c) Peanuts (1/4 c) Lentils (1 c) Pork (3 oz) Beef (3 oz) Trout (3 oz) Chicken (3 oz) 2% Milk (1 c) Cheddar cheese (1. 5 oz) Orange juice (1 c) Kiwi (2 med) Apple (1 med) Corn (1/2 c) Asparagus (1/2 c) Spinach, raw (1 c) Oatmeal (1 c) Spaghetti (1 c) Brown rice (1 c) White bread (2 sl) Whole-wheat bread (2 sl) 0 0. 2 0. 4 0. 6 0. 8 Thiamin (mg) 1. 0 1. 2 243 FIGURE 8. 6 Thiamin content of selections from each group of the Food Guide Pyramid. The dashed line represents the RDA for adult men. Pork is a better source of thiamin than other meats. (Randy Mayor/Foodpix/PictureArts Corp. ) The recommended intake for thiamin can be met by eating a varied diet You can meet your needs for thiamin by snacking on sun? ower seeds and having a serving of roast pork for dinner. These foods are exceptionally good sources of thiamin. Together 3 ounces of pork and a quarter cup of sun? ower seeds provide 1. 5 mg of thiamin, well above the RDA, which is 1. mg per day for adult men age 19 and older and 1. 1 mg per day for adult women 19 and older. 2 But even a diet that doesn’t include these foods can meet your thiamin needs as long as you make nutritious choices such as those recommended by the Food Guide Pyramid (Figure 8. 6). Legumes, nuts, and seeds are good sources. Grains are also good sources; thiamin is found in the bran of whole grains and i t is added to enriched re? ned grains. A large proportion of the thiamin consumed in the United States comes from enriched grains used in foods such as baked goods. Some breakfast cereals are forti? d with so much additional thiamin that a single bowlful contains more than the RDA. Although it is easy to meet thiamin needs some of the thiamin in foods may be destroyed during cooking or storage because it is sensitive to heat, oxygen, and low-acid conditions. Thiamin availability is also affected by the presence of antithiamin factors that destroy the vitamin. There are enzymes in raw shell? sh and freshwater ? sh that degrade thiamin during food storage and preparation and during passage through the gastrointestinal tract. These enzymes are destroyed by cooking so they are only a concern in foods consumed raw. Other antithiamin factors that are not inactivated by cooking are found in tea, coffee, betel nuts, blueberries, and red cabbage. Habitual consumption of foods containing antithiamin factors increases the risk of thiamin de? ciency. 2 Despite the fact that intakes of thiamin above the RDA have not been shown to be bene? cial, many supplements contain up to 50 mg of thiamin and promise that they will provide â€Å"more energy. † Although thiamin is needed to produce energy, unless it is de? cient, increasing thiamin intake does not increase the ability to produce energy. There is no UL for thiamin since no toxicity has been reported when excess is consumed from either food or supplements. 2 Enriched grains have thiamin as well as ribo? avin, niacin, and iron added to them (see Chapter 4). * Remember 244 Chapter 8 The Vitamins Ribo? avin: a bright yellow vitamin Ribo? avin is a water-soluble vitamin that provides a visible indicator when you consume too much of it. Excess is excreted in your urine—turning it a bright ? uorescent yellow. The color may surprise you but it is harmless. No adverse effects have been reported from high doses of ribo? vin from foods or supplements. FIGURE 8. 7 Milk is packaged in opaque or cloudy containers to protect its ribo? avin from destruction by light. (Charles D. Winters) Milk is the best source of ribo? avin in the North American diet Ever wonder why milk comes in opaque cardboard or cloudy plastic containers? The reason is that it is one of the best sources of ribo? avin in our diet and ribo? avin is destroy ed by light. If your milk was in a clear glass bottle and sat in a lighted grocery store display case for several days much of the ribo? avin would be destroyed. The most ribo? vin-friendly milk containers are opaque so the ribo? avin is fully protected from light (Figure 8. 7). Other major dietary sources of ribo? avin include other dairy products, liver, red meat, poultry, ? sh, whole grains, and enriched breads and cereals. Vegetable sources include asparagus, broccoli, mushrooms, and leafy green vegetables such as spinach. The RDA for ribo? avin for adult men age 19 and older is 1. 3 mg per day and for adult women 19 and older, 1. 1 mg per day. 3 Two cups of milk provide about half the amount of ribo? avin recommended for a typical adult. If you do not include milk in your diet you can meet your ribo? avin needs by including two to three servings of meat and four to ? ve servings of enriched grain products and high-ribo? avin vegetables such as spinach (Figure 8. 8). Ribo? avin is needed to produce energy from carbohydrate, fat, and protein Ribo? avin has two active coenzyme forms that function in producing energy from carbohydrate, fat, and protein. Ribo? avin is also involved directly or indirectly in converting a number of other vitamins, including folate, niacin, vitamin B6, and vitamin K, into their active forms. When ribo? vin is de? cient, injuries heal poorly because new cells cannot grow to replace the damaged ones. Tissues that grow most rapidly, such as the skin and the lin- RDA Sunflower seeds (1/4 c) Walnuts (1/4 c) Peanuts (1/4 c) Lentils (1 c) Pork (3 oz) Beef (3 oz) Trout (3 oz) Chicken (3 oz) 2% Milk (1 c) Cheddar cheese (1. 5 oz) Orange juice (1 c) Kiwi (2 med) Apple (1 med) Corn (1/2 c) Asparagus (1 /2 c) Spinach, raw (1 c) FIGURE 8. 8 Ribo? avin content of selections from each group of the Food Guide Pyramid. The dashed line represents the RDA for adult men. Milk is an exceptionally good source of ribo? avin. Corbis Images) Oatmeal (1 c) Spaghetti (1 c) Brown rice (1 c) White bread (2 sl) Whole-wheat bread (2 sl) 0 0. 4 0. 8 Riboflavin (mg) 1. 2 Many B Vitamins Are Essential for Energy Production 245 ings of the eyes, mouth, and tongue, are the ? rst to be affected. This causes symptoms such as cracking of the lips and at the corners of the mouth; increased sensitivity to light; burning, tearing, and itching of the eyes; and ? aking of the skin around the nose, eyebrows, and earlobes. A de? ciency of ribo? avin rarely occurs alone; it usually occurs in conjunction with de? ciencies of other B vitamins. This is because the same foods provide many of the B vitamins. Because ribo? avin is needed to convert other vitamins into their active forms, some of the symptoms seen with ribo? avin de? ciency re? ect de? ciencies of these other nutrients. Niacin: de? ciency caused an epidemic of mental illness In the early 1900’s psychiatric hospitals in the southeastern United States were ? lled with patients with the niacin-de? ciency disease pellagra. At the time, no one knew what caused it but the prime suspects were toxins or microorganisms. The mystery of pellagra was ? nally unraveled by Dr. Joseph Goldberger, who was sent by the U. S. Public Health Service to investigate the pellagra epidemic. He observed that individuals in institutions such as hospitals, orphanages, and prisons suffered from pellagra, but the staff did not. If pellagra were an infectious disease, both populations would be equally affected. Dr. Goldberger proposed that pellagra was due to a de? ciency in the diet. To test his hypothesis, he added nutritious foods such as fresh meats, milk, and eggs to the diet of children in orphanages. The symptoms of pellagra disappeared, supporting his hypothesis that pellagra is due to a de? ciency of something in the diet. In another experiment he was able to induce pellagra in healthy prison inmates by feeding them an unhealthy diet. The missing dietary component was later identi? ed as the water-soluble B vitamin niacin. L Pellagra The disease resulting from a * de? ciency of niacin. A niacin de? ciency causes dermatitis, diarrhea, and dementia The need for niacin is so widespread in metabolism that a de? ciency causes major changes throughout the body. The early symptoms of pellagra include fatigue, decreased appetite, and indigestion. These are followed by symptoms that can be remembered as the three D’s: dermatitis, diarrhea, dementia. If left untreated, niacin de? ciency results in a fourth D—death. Niacin coenzymes function in glucose metabolism and in reactions that synthesize fatty acids and cholesterol (see Figure 8. 3). There are two forms of niacin: nicotinic acid and nicotinamide. Either form can be used by the body to make the active coenzyme forms. Niacin is found in meats, legumes, and grains Meat and ? sh are good sources of niacin (Figure 8. 9). Other sources include legumes, wheat bran, and peanuts. Niacin added to enriched grains provides much of the usable niacin in the North American diet. Niacin can also be synthesized in the body from the essential amino acid tryptophan. Tryptophan, however, is only used to make niacin if enough is available to ? rst meet the needs of protein synthesis. When the diet is low in tryptophan, it is not used to synthesize niacin. The reason pellagra was prevalent in the South in the early 1900’s is because the local diet among the poor consisted of corn meal, molasses, and fatback or salt pork— all poor sources of both niacin and protein. Corn is low in tryptophan and the niacin found naturally in corn is bound to other molecules and therefore not well absorbed. Molasses contains essentially no protein or niacin and salt pork is almost pure fat, so it does not contain enough protein to both meet protein needs and synthesize niacin. Although corn-based diets such as this one are historically associated with the appearance of niacin de? ciency it has not been a problem in Mexico and Central American countries. One reason may be because the treatment of corn with lime water, as is done during the making of tortillas, enhances the availability of niacin (Figure 8. 10). The diet in these regions also includes legumes, which provide both niacin and a source of tryptophan for the synthesis of niacin. In searching for the cause of pellagra, Dr. Goldberger and his coworkers ingested blood, nasal secretions, feces, and urine from patients with the disease—none of them developed pellagra. This helped to disprove the hypothesis that pellagra was an infectious disease. 246 Chapter 8 The Vitamins RDA Sunflower seeds (1/4 c) Walnuts (1/4 c) Peanuts (1/4 c) Lentils (1 c) Pork (3 oz) Beef (3 oz) Trout (3 oz) Chicken (3 oz) 2% Milk (1 c) Cheddar cheese (1. 5 oz) Orange juice (1 c) Kiwi (2 med) Apple (1 med) Corn (1/2 c) Asparagus (1/2 c) Spinach, raw (1 c) FIGURE 8. 9 Niacin content of selections from each group of the Food Guide Pyramid. The dashed line represents the RDA for adult men. Meat, legumes, and grains are good sources of the vitamin. (PhotoDisc, Inc. /Getty Images) Oatmeal (1 c) Spaghetti (1 c) Brown rice (1 c) White bread (2 sl) Whole-wheat bread (2 sl) 0 2 4 6 8 10 Niacin (mg) 12 14 16 L Niacin equivalents (NEs) The * measure used to express the amount of niacin present in food, including that which can be made from its precursor, tryptophan. One NE is equal to 1 mg of niacin or 60 mg of tryptophan. Today, as a result of the enrichment of grains, including corn meal, with niacin, thiamin, ribo? vin, and iron, pellagra is rare in the United States but it remains common in India and parts of China and Africa. Efforts to eradicate this de? ciency include the development of new varieties of corn that provide more available niacin and more tryptophan than traditional varieties. Because some of the requirement for niacin can be met by the synthesis of niacin from tryptophan, the RDA is expressed as niacin equi valents (NEs). One NE is equal to 1 mg of niacin or 60 mg of tryptophan, the amount needed to make 1 mg of niacin. 3 To estimate the niacin contributed by high-protein foods, protein is considered to be about 1% tryptophan. The RDA for adult men and women of all ages is 16 and 14 mg NE per day, respectively. A medium chicken breast and a cup of steamed asparagus provide this amount. FIGURE 8. 10 Tortillas, eaten in Mexico and other Latin American countries, provide niacin because the corn is treated with lime water, making the niacin available for absorption. (Jeff Greenberg/Photo Researchers) Many B Vitamins Are Essential for Energy Production 247 High-dose niacin supplements can be toxic There is no evidence of any adverse effects from consumption of niacin naturally occurring in foods, but supplements can be toxic. The adverse effects of high intakes of niacin include ? ushing of the skin, a tingling sensation in the hands and feet, a red skin rash, nausea, vomiting, diarrhea, high blood sugar levels, abnormalities in liver function, and blurred vision. The UL for adults is 35 mg, but high-dose supplements of one form of niacin (50 mg or greater) are used under medical supervision to treat elevated blood cholesterol (see Chapter 5). Another form is under investigation for its bene? ts in the prevention and treatment of diabetes. When vitamins are taken in large doses to treat diseases that are not due to vitamin de? iencies, they are really being used as drugs rather than vitamins. Biotin: eggs contain it but can block its use You probably know that you shouldn’t eat raw eggs because they can contain harmful bacteria, but did you know that eating raw eggs could cause a biotin de? ciency? Raw egg whites contain a protein called avidin that tightly binds biotin and prevents its absorption. Biotin was discovered when rats fed protein derived from raw egg whites developed a syndrome of hair loss, dermatitis, and neuromuscular dysfunction. Thoroughly cooking eggs kills bacteria and denatures avidin so that it cannot bind biotin (Figure 8. 1). FIGURE 8. 11 Raw eggs are often used to make high-protein health drinks. This is not recommended because raw eggs may contain bacteria that can make you sick, and egg whites contain a protein that makes biotin unavailable. (Charles D. Winters) Biotin is important in energy production and glucose synthesis Biotin is a coenzyme for a group of enzymes that add an acid group to molecules. It functions in energy production and in glucose synthesis. It is also important in the metabolism of fatty acids and amino acids (see Figure 8. 3). Although biotin de? iency is uncommon, it has been observed in those frequently consuming raw egg whites as well as people with malabsorption or protein-energy malnutrition, those receiving intravenous fe edings lacking biotin, and those taking certain anticonvulsant drugs for long periods. 3 Biotin de? ciency in humans causes nausea, thinning hair, loss of hair color, a red skin rash, depression, lethargy, hallucinations, and tingling of the extremities. Biotin is consumed in the diet and made by bacteria in the gut Good sources of biotin in the diet include cooked eggs, liver, yogurt, and nuts. Fruit and meat are poor sources. Biotin is also synthesized by bacteria in the gastrointestinal tract. Some of this is absorbed into the body and contributes to our biotin needs. An AI of 30 mg per day has been established for adults based on the amount of biotin found in a typical North American diet. High doses of biotin have not resulted in toxicity symptoms; there is no UL for biotin. Pantothenic acid: widely distributed in food and widely used in the body Pantothenic acid, which gets its name from the Greek word pantos (meaning â€Å"from everywhere†), is widely distributed in foods. It is particularly abundant in meat, eggs, whole grains, and legumes. It is found in lesser amounts in milk, vegetables, and fruits. In addition to being â€Å"from everywhere† in the diet, pantothenic acid seems to be needed everywhere in the body. It is part of a key coenzyme needed for the breakdown of carbohydrates, fatty acids, and amino acids as well as the modi? cation of proteins and the synthesis of neurotransmitters, steroid hormones, and hemoglobin. Pantothenic acid is also part of a coenzyme essential for the synthesis of cholesterol and fatty acids (see Figure 8. 3). The wide distribution of pantothenic acid in foods makes de? ciency rare in humans. It may occur as part of a multiple B vitamin de? iency resulting from malnutrition or chronic alcoholism. The AI is 5 mg per day for adults. Pantothenic acid is relatively nontoxic and there are not suf? cient data to establish a UL. 3 248 Chapter 8 The Vitamins Vitamin B6 Is Important in Protein Metabolism Vitamin B6 is one of only two B vitamins that we still know by its number. The ch emical name for vitamin B6 is pyridoxine but we rarely hear it called this. The important role of vitamin B6 in amino acid metabolism distinguishes it from the other B vitamins. Vitamin B6 is needed to synthesize and break down amino acids Vitamin B6 has three forms—pyridoxal, pyridoxine, and pyridoxamine. These can be converted into the active coenzyme form, pyridoxal phosphate, which is needed for the activity of more than 100 enzymes involved in the metabolism of carbohydrate, fat, and protein. It is particularly important in amino acid synthesis and breakdown; without vitamin B6 the non-essential amino acids cannot be made in the body (Figure 8. 12). Pyridoxal phosphate is needed to synthesize hemoglobin, the oxygen-carrying protein in red blood cells, and is important for the immune system because it is needed to form white blood cells. It is also needed for the conversion of tryptophan to niacin, the release of glucose from the carbohydrate storage molecule glycogen, the synthesis of certain neurotransmitters, and the synthesis of the lipids that are part of the myelin coating on nerves, which is essential for normal transmission of nerve signals. Vitamin B6 de? ciency causes numbness and tingling Vitamin B6 de? ciency causes neurological symptoms including numbness and tingling in the hands and feet as well as depression, headaches, confusion, and seizures. These symptoms may be related to the role of vitamin B6 in neurotransmitter synthesis and myelin formation. Anemia also occurs in vitamin B6 de? ciency, because without B6 hemoglobin cannot be synthesized normally. Other de? ciency symptoms such as poor growth, skin lesions, and decreased antibody formation may occur because of the central role vitamin B6 plays in protein and energy metabolism. Since vitamin B6 is needed for amino acid metabolism, the onset of a de? ciency can be hastened by a diet that is low in vitamin B6 but high in protein. H H2N C C O OH Amino acids NH2 C O OH B6 Energy production and glucose synthesis B6 B6 FIGURE 8. 12 Vitamin B6 is essential for many different types of reactions involving amino acids. It is needed to remove the acid group so neurotransmitters can be synthesized, to remove the amino group so what remains can be used to produce energy or synthesize glucose, and to transfer an amino group to make a new amino acid. Neurotransmitter synthesis NH2 Synthesis of nonessential amino acids Vitamin B6 Is Important in Protein Metabolism Folic acid from food and supplements 249 DNA synthesis Active folate Vitamin B12 Inactive folate Methionine High levels in the FIGURE 8. 13 blood increase cardiovascular The accumulation of homocysteine in the blood is associated with an disease risk Homocysteine Vitamin B6 increased risk of heart disease. Vitamins B6, B12, and folate, are needed to keep homocysteine levels in the normal range. Vitamin B6 is needed to break down homocysteine. Vitamin B12 and folate are needed to convert homocysteine to methionine. Vitamin B6 status is related to heart disease risk Vitamin B6 is needed to break down the amino acid homocysteine. If B6 levels are low, homocysteine can’t be broken down and levels rise. Even a mild elevation in blood homocysteine levels has been shown to be a risk factor for heart disease (Figure 8. 13). Two other B vitamins, folate and vitamin B12 are also involved in homocysteine metabolism. These are needed to convert homocysteine to the amino acid methionine. If they are unavailable, homocysteine levels will increase. A study that examined the effect of folate and vitamin B6 intake in women found that those with the highest levels in their diets had about half the risk of coronary heart disease as women wit h the lowest levels. 5 Both animal and plant foods are good sources of vitamin B6 Animal sources of vitamin B6 include chicken, ? sh, pork, and organ meats. Good plant sources include whole wheat products, brown rice, soybeans, sun? ower seeds, and some fruits and vegetables such as bananas, broccoli, and spinach (Figure 8. 14). Re? ned grains, like white rice and white bread, are not good sources of vitamin B6, because the vitamin is lost in re? ning whole grains but is not added back in enrichment. It is added to many forti? ed breakfast cereals; these make an important contribution to vitamin B6 intake. 6 It is destroyed by heat and light, so it can easily be lost in processing. The RDA for vitamin B6 is 1. 3 mg per day for both adult men and women 19 to 50 years of age. A 3-ounce (85-g) serving of chicken, ? sh, or pork, or half a baked potato, provides about one-fourth of the RDA for an average adult; a banana provides about one-third. Too much vitamin B6 is toxic For years people assumed that because water-soluble vitamins were excreted in the urine they could not cause toxic reactions. However, reports in the 1980’s of seve re nerve impairment in individuals taking 2 to 6 g of pyridoxine per day showed these assumptions to be false. 7 The reactions of some supplement users were so severe that they were unable to walk; symptoms improved when the pyridoxine supplements were stopped. The UL for adults is set at 100 mg per day from food and supplements. 3 Despite the potential for toxicity, high-dose supplements of vitamin B6 containing 100 mg per dose (5000% of the Daily Value) are available over the counter, making it easy to obtain a dose that exceeds the UL. These supplements are taken to reduce the symptoms of premenstrual syndrome (PMS), treat carpal tunnel syndrome, and strengthen immune function. Although studies have not found a relationship between carpal tunnel syndrome and vitamin B6 status, some studies report that low-dose supplements of vitamin B6 may reduce symptoms of PMS and improve immune function. Individuals with an inherited disease called homocysteinuria have extremely high levels of homocysteine in their blood and may have heart attacks and strokes by the age of 2. 250 Chapter 8 The Vitamins RDA Sunflower seeds (1/4 c) Walnuts (1/4 c) Peanuts (1/4 c) Lentils (1 c) Pork (3 oz) Beef (3 oz) Trout (3 oz) Chicken (3 oz) 2% Milk (1 c) Cheddar che ese (1. 5 oz) Orange juice (1 c) Kiwi (2 med) Apple (1 med) Corn (1/2 c) Asparagus (1/2 c) Spinach, raw (1 c) Oatmeal (1 c) Spaghetti (1 c) Brown rice (1 c) White bread (2 sl) Whole-wheat bread (2 sl) 0 0. 0. 8 Vitamin B6 (mg) 1. 2 FIGURE 8. 14 Vitamin B6 content of selections from each group of the Food Guide Pyramid. The dashed line represents the RDA for men and women up to 50 years of age. The best sources are meats, legumes, and whole grains. (David Bishop/Foodpix/PictureArts Corp. ) PMS causes mood swings, food cravings, bloating, tension, depression, headaches, acne, breast tenderness, anxiety, temper outbursts, and over 100 other symptoms. Because vitamin B6 is needed for the synthesis of the neurotransmitters serotonin and dopamine, insuf? ient vitamin B6 has been suggested to cause the anxiety, irritability, and depression associated with PMS by reducing levels of these neurotransmitters. Trials on the effect of vitamin B6 supplements on PMS have had con? icting resultsâ⠂¬â€ in some cases low-dose supplements appear to be effective in reducing symptoms. 9 Vitamin B6 supplements have been found to improve immune function in older adults, but the reason for the improvement is unclear. 10 Immune function can be impaired by a de? ciency of any nutrient that hinders cell growth and division. Therefore, one of the most common claims for vitamin supplements in general is that they improve immune function. Vitamin B6 is no exception. Since the elderly frequently have low intakes of vitamin B6, it is unclear whether the bene? cial effects of supplements are due to an improvement in vitamin B6 status or immune system stimulation. Folate and Vitamin B12 Are Needed for Cell Division Inside the nucleus of every cell is the DNA that holds the genetic code. Before a cell can divide it must make a copy of its DNA. The B vitamin folate is needed for the synthesis of DNA and vitamin B12 is needed to keep folate active. Therefore if either B12 or folate is missing, DNA cannot be copied and new cells cannot be made correctly. As a result of this interdependency, many of the same symptoms are seen when either vitamin B12 or folate are de? cient. Folate: important for rapidly dividing cells A number of different forms of folate are needed for the synthesis of DNA and the metabolism of some amino acids. Because folate is needed for cells to replicate, it is particularly important in tissues where cells are dividing rapidly such the bone marrow, where red blood cells are made, and the developing tissues of an unborn baby. Folate and Vitamin B12 Are Needed for Cell Division 251 folate adequate folate deficient Normal cell division Red blood cells Red blood cell precursor FIGURE 8. 15 Cells are unable to divide (megaloblast) Macrocyte Megaloblastic or macrocytic anemia occurs when developing blood cells are unable to divide, leaving large immature red blood cells (megaloblasts) and large mature red blood cells (macrocytes). Folate de? ciency results in anemia One of the most notable symptoms of folate de? ciency is anemia. Without folate, developing red blood cells cannot divide. Instead, they just grow bigger (Figure 8. 15). Fewer mature red cells are produced so the oxygen-carrying capacity of the blood is reduced. This condition is called megaloblastic or macrocytic anemia. Other symptoms of folate de? ciency include poor growth, problems in nerve development and function, diarrhea, and in? ammation of the tongue. Groups most at risk of a folate de? ciency include pregnant women and premature infants because of their rapid rate of cell division and growth; the elderly because of their limited intake of foods high in folate; alcoholics because alcohol inhibits folate absorption; and tobacco smokers because smoke inactivates folate in the cells lining the lungs. Folate intake is related to neural tube defects A low folate intake increases the risk of birth defects that affect the brain and spinal cord called neural tube defects (Figure 8. 16). The exact role of folate in neural tube development is not known, but it is necessary for a critical step called neural tube closure. Neural tube closure occurs ve ry early in pregnancy—only 28 days after conception—when most women may not yet even know they are pregnant. Therefore to reduce the risk of these defects, folate status must be adequate before a pregnancy begins and during the early critical days of pregnancy (see Chapter 12). However, folate is not the only factor contributing to neural tube defects. Not every pregnant woman with low folate levels gives birth to a child with a neural tube defect. Instead, these birth defects are probably due to a combination of factors that are aggravated by low folate levels. Folate status may affect heart disease and cancer risk Low folate intake may increase the risk of heart disease because of its relation to homocysteine levels (see Figure 8. 13). Low folate status may also increase the risk of developing cancer L Megaloblastic or macrocytic anemia * A condition in which there are abnormally large immature and mature red blood cells and a reduction in the total number of red blood cells and the oxygen-carrying capacity of the blood. L Neural tube defects Irregularities in * the formation of the portion of the embryo that develops into the brain and spinal cord. These occur early in development and result in brain and spinal cord abnormalities. Vertebrae Spinal cord Vertebrae Spinal cord FIGURE 8. 16 Early in pregnancy, the neural tube develops into the brain and spinal cord. If folate is inadequate during neural tube closure, neural tube defects such as spina bi? da, shown here, occur more frequently. In spina bi? da the bones that make up the back do not completely surround the spinal cord, allowing membranes, ? uid, and, in severe cases, the nerves of the spinal cord to bulge out where they are unprotected. Normal spine Spine with spina bifida 252 Chapter 8 The Vitamins For more information on folic acid and birth defects, go to the Spina Bifida Association of America at www. sbaa. org of the uterus, cervix, lungs, stomach, esophagus, and colon. Although folate de? iency does not cause cancer, it has been hypothesized that low folate intake enhances an underlying predisposition to cancer. The relation between folate and cancer is strongest for colon cancer. Alcohol consumption greatly increases the cancer risk associated with a low folate diet. 11 L Dietary folate equivalent (DFE) A unit * used to express the amount of folate available to the body that accounts for the higher bioavailability of folic acid in supplements and enriched foods compared to folate found naturally in foods. One DFE is equivalent to 1 g of folate naturally occurring in food, 0. 6 g of synthetic folic acid from forti? d food or supplements consumed with food, or 0. 5 g of synthetic folic acid consumed on an empty stomach. Vegetables, legumes, oranges, and grains are good sources of folate Asparagus, oranges, legumes, liver, and yeast are excellent food sources of folate. Fair sources include grains, corn, snap beans, mustard greens, and broccoli, as well as some nuts. Small amounts are found in meats, cheese, milk, fruits, and other vegetables (Figure 8. 17). Folic acid is added to enriched grain products, including enriched breads, ? ours, corn meal, pasta, grits, and rice. If you look at the label on a bag of enriched ? ur you will see that it is forti? ed with folic acid. Folic acid is a stable form of folate that rarely occurs naturally in food but is used in supplements and forti? ed foods; it is more easily absorbed than natural folate. In the 3-year period after the forti? cation of grain products with folic acid, the incidence of neural tube defects decreased by 25%. 12 Women of childbearing age need extra folate The RDA for folate is set at 400 g dietary folate equivalents (DFEs) per day for adult men and women. Expressing needs in DFEs allows one unit to be used for all the forms of folate; one DFE is equal to 1 g of food folate, 0. g of synthetic folic acid from forti? ed food or supplements consumed with food, or 0. 5 g of synthetic folic acid consumed on an empty stomach. Because supplementing folic acid early in pregnancy has been shown to reduce neural tube defects, a special recommendation is made for women capable of becoming pregnant; 400 g of synthetic folic acid from forti? ed foods and/or supplements is recommended in addition to the food folate consumed in RDA Sunflower seeds (1/4 c) Walnuts (1/4 c) Peanuts (1/4 c) Lentils (1 c) Pork (3 oz) Beef (3 oz) Trout (3 oz) Chicken (3 oz) 2% Milk (1 c) Cheddar cheese (1. oz) Orange juice (1 c) Kiwi (2 med) Apple (1 med) Corn (1/2 c) Asparagus (1/2 c) Spinach, raw (1 c) Oatmeal (1 c) Spaghetti (1 c) Brown rice (1 c) White bread (2 sl) Whole-wheat bread (2 sl) 0 100 200 Folate ( µg DFE) 300 400 FIGURE 8. 17 Folate content of selections from each group of the Food Guide Pyramid. The dashed line represents the RDA for adults. Legumes, forti? ed foods, and some fruits and vegetables are good sources. (George Semple) Folate and Vitamin B12 Are Needed for Cell Division 253 PIECE IT TOGETHER Is It Hard to Meet Folate Recommendations? Marcia would like to have a baby but before she tries to conceive, she wants to be sure she is in the best condition possible. She consults her physician who gives her a clean bill of health but suggests she make sure she is getting enough folate. women who are capable of becoming pregnant should consume 400 g of folic acid from forti? ed foods or supplements each day in addition to the folate found in a varied diet. Folic acid is added to enriched grains, so it can be found in any food that contains enriched grains; you can check the ingredient list to see if the food you have chosen contains added folic acid. The percent Daily Value includes both the natural folate and added folic acid. W HY IS FOLATE A CONCERN FOR WOMEN CAPABLE OF BECOMING PREGNANT ? M Research shows that consuming extra folic acid can reduce the risk of a type of birth defect called a neural tube defect that affects an unborn child’s brain or spinal cord. For the extra folic acid to be bene? cial, it must be consumed for at least a month before conception and continued for a month after. Since many pregnancies are not planned, it is recommended that all women of childbearing age consume 400 g of folic acid from forti? d foods or supplements. Marcia records her food intake for 1 day to determine her folate intake: Food Breakfast Oatmeal, regular Milk Banana Orange juice Coffee Lunch Hamburger Hamburger bun French fries Coke Apple Dinner Chicken Refried beans White rice Tortilla Salad Salad dressing Milk Cake Total Servings 1 cup 1 cup 1 medium 8 ounces 1 cup 1 1 20 pieces 12 ounces 1 medium 3 ounces 1/2 cup 1 cup 1 1 cup 1 Tbsp 1 cup 1 piece Total Folate ( g) 2 12 22 75 0 11 32 24 0 4 4 106 80 60 64 1 12 32 541 g FOLATE INTAKE MEET THE W HICH FOODS IN M ARCIA’ S DIET ARE HIGHEST IN FOLATE ? O F THESE , WHICH DO YOU THINK HAVE BEEN FORTIFIED WITH FOLIC ACID ? M Food Rice Orange juice Your answers: Amount 80 g 75 g Natural Forti? ed W HY IS THE OATMEAL LOW IN FOLATE BUT THE OTHER GRAIN PRODUCTS ARE GOOD FOLATE SOURCES ? M Oatmeal is a whole grain, so it has not been forti? ed with folic acid. The other grain products in her diet, such as the white rice, tortilla, and hamburger bun, are re? ned so they contain added folic acid. Even though Marcia is trying to increase her intake of the folic acid form of this vitamin she should not pass up whole grains—they are good sources of most B vitamins, minerals, and ? er. L IST SOME MODIFICATIONS M ARCIA COULD MAKE IN HER DIET TO PROVIDE THE RECOMMENDED AMOUNTS AND FORMS OF FOLATE ? M Your answer: W OULD YOU RECOMMEND M ARCIA TAKE A FOLATE SUPPLEMENT ? D OES M ARCIA’ S RDA? Your answer: M Yes. Marica consumes 541 g of folate, which is greater than the RDA of 400 g DFE, but her doctor told her that M 254 Chapter 8 The Vitamins Not everyone needs a folate supplement. If you are male or a female who is too young or too old to have a baby, the amount of folate you get from a healthy diet will meet your needs. Even women of childbearing age can get enough folic acid without a supplement if they eat enough folic acid forti? ed foods. a varied diet. The folic acid form is recommended because it is the form that has been shown to reduce birth defects. This recommendation is made for all women of childbearing age because folate is needed very early in a pregnancy—before most women are aware that they are pregnant. To get 400 g of folic acid, you would need to eat 4 to 6 servings of forti? ed grain products each day or take a supplement containing folic acid. Excess folate can mask anemia caused by vitamin B12 de? ciency Although extra folate is recommended for pregnant women, too much is a concern for some groups. There is no known folate toxicity, but a high intake may mask the early symptoms of vitamin B12 de? ciency, allowing it to go untreated so irreversible nerve damage can occur. The UL for adults is set at 1000 g per day of folate from supplements and/or forti? ed foods. This value was determined based on the progression of neurological symptoms seen in patients who are de? cient in vitamin B12 and taking folate supplements. L Pernicious anemia An anemia * resulting from vitamin B de? ciency that 12 Vitamin B12: absorption requires intrinsic factor If you lived in the early 1900’s and developed a condition called pernicious anemia, it was a death sentence. There was no cure. In the 1920’s researchers George Minot and William Murphy pursued their belief that pernicious anemia could be cured by something in the diet. Their experiments were able to restore good health to patients by feeding them about 4 to 8 ounces of slightly cooked liver at every meal. Today we know that liver contains high levels of vitamin B12. We also know that pernicious anemia is not actually caused by a lack of the vitamin in the diet, but rather an inability to absorb the vitamin. Vitamin B12 absorption requires a protein called intrinsic factor that is produced by cells in the stomach lining. With the help of stomach acid, intrinsic factor binds to vitamin B12 and this vitamin B12-intrinsic factor complex is then absorbed in the small intestine. When very large amounts of the vitamin are consumed, some can be absorbed without intrinsic factor. This is why Minot and Murphy were able to cure pernicious anemia with extremely high dietary doses of the vitamin. Today, pernicious anemia is treated with injections of vitamin B12 rather than plates full of liver. occurs due to a lack of a protein called intrinsic factor needed to absorb dietary vitamin B12. L Intrinsic factor A protein produced * in the stomach that is needed for the absorption of adequate amounts of vitamin B12. L Cobalamin The chemical term for * vitamin B . 12 Vitamin B12 is needed for nerve function Vitamin B12, also known as cobalamin, is necessary for the maintenance of myelin, which is the coating that insulates nerves and is essential for nerve transmission. Vitamin B12 is also needed for the production of energy from certain fatty acids and to convert homocysteine to methionine (see Figure 8. 13). This reaction also converts folate from an inactive form to a form that functions in DNA synthesis. Because of the need for vitamin B12 in folate metabolism, a de? ciency can cause a secondary folate de? ciency and, consequently, macrocytic anemia. Symptoms of vitamin B12 de? ciency include an increase in blood homocysteine levels and anemia that is indistinguishable from that seen in folate de? ciency. Other symptoms include numbness and tingling, bnormalities in gait, memory loss, and disorientation due to degeneration of the myelin that coats the nerves, spinal cord, and brain. If not treated, this eventually causes paralysis and death. Consuming extra folate can mask a vitamin B12 de? ciency When the diet is de? cient in vitamin B12, consuming extra folate can mask the vitamin B12 de? ciency by preventing the appearance of anemia. If the d e? ciency is not treated, the other symptoms of B12 de? ciency, such as nerve damage, progress and can be irreversible. This connection between folate and vitamin B12 has raised concerns that our folate-forti? d food supply may allow B12 de? ciencies to go unnoticed. So far, this