Vitamins are generally defined as “organic molecules which are required in the diet, because
they are essential to normal function, yet the body does not manufacture them,” or does not make
them in sufficient quantities to meet the need for them. Vitamins are not digested, but absorbed
whole [if they could be digested, and reassembled by the body, they would not be vitamins by the
above definition]. They are not metabolized for energy capture, because their function is too
Some vitamins have been shown to function as co-enzymes. It is possible that all of the vitamins will eventually be found to serve as co-enzymes. We can begin to understand the concept of enzyme - co-enzyme complexes by analogy to home heating systems of your great-grandparents and your grandparents. In the 19th and early 20th Centuries, many homes were heated by free-standing, cast-iron stoves [“Ben Franklin” stoves, after the inventor] which burned wood or coal. When the room became chilly, we would put another log on the fire (or add a scoop of coal); and when the room became too warm, we had to open the windows. By current standards this is highly inefficient, but was an improvement over the fireplace, because most of the heat from a fireplace goes up the chimney. The free-standing cast-iron stove used the fire to heat the stove [until it was too hot to touch], then radiated most of the heat into the room in all directions [so the stoves were placed toward the center of the room rather than being stuck in an outside wall like the fireplace]. Around 1885, Mr Butz invented a device to regulate the damper on the stove automatically [closing the damper slows the fire by restricting air flow, opening the damper allows the fire to burn hotter due to higher air flow], and by 1895 these new-fangled devices were being advertised for home applications (data from www.honeywell.com/sites/honeywell/ourhistory.htm, downloaded by Dr LaFrance on February 22, 2009). From this long winded story, the Franklin stove is the analogy of an enzyme-driven reaction, which is not as efficient as it could be, but a great improvenment over the non-enzyme driven reaction (the fireplace). The automatic damper control, attached to the stove, is the analogy of the co-enzyme added to the enzyme. The enzyme drives the reaction, while the co-enzyme helps regulate the speed of the reaction. The following table gives an over-simplified version of the enzme versus the enzyme - co-enzyme complex:
There is a considerable amount of current research looking into the detailed role of vitamins, so it
becomes more important to know how to look up any vitamin which becomes “interesting”
because of its possible relationship to your patient's health or wellness issues than it is to waste
time learning ‘facts’ that are being revised by on-going research. Translated into
English, that means that you learn only what you need, as you find the need, for specific care
plans; and that you must check for newer information each time the issue comes up in a care plan. To
find updated information, you can google “vitamins” (or better the specific vitamin of
interest) and select a website ending in “.gov” (such as the National Institutes of Health
[NIH], U.S. National Library of Medicine [NLM]
Some websites ending in dot-edu are some professor's Nutrition class notes (like mine); most of these
are updated relatively often (as long as the professor is still teaching the course), but not as
often as the dot-gov sites (which we [professors] use, in addition to current published research in
professional journals, to update our sites). Most dot-com websites are selling something other than
For the time being, what you need to know is the nutritional status of the person whose diet you tracked for Quiz 1. You should, by now, already know the average daily percentage of RDA for various vitamins (and other nutrients) for this person. For any vitamin for which intake is too low, or too high, compared to the RDA, you will need to know the possible consequences for the person if he/she continues their present diet for a long time. You can find this information by clicking on the links in the table below
or by looking in the tables in Nutrition Now, 5th ed (Table 20.2 starting on pg. 20-4). Column 5 lists primary food sources [but Table 20.4 starting on pg 20-14 has more complete information on vitamin density of foods]; and column 6 provides highlights and comments
[the information on food sources in my table lists only the higher density, non-enriched foods; complete information can be found at the USDA Agricultural Research Center.
|Vitamin A||B complex|
|Vitamin E||Riboflavin (B2)|
|Vitamin D||Niacin (B3)|
|Vitamin K||Vitamin B6|
| ||Pantothenic acid|
For example, if your patient has a low percentage of AI for Vitamin K [I chose this one because I
have observed extremely low intakes, less than 10% AI, in data submitted for this class in the past],
you can find Vitamin K in Table 20.2 on page 20-10 & 20-11. From column 3, we find that deficiency
leads to bruising (easily mistaken for serious physical abuse) and decreased calcium in bones. The
text states that deficiency is rare, but I would note that “The incidence of osteoporosis is far
less in many other countries than in the United States” (text pg. 23-10), suggesting to me that
sub-clinical deficiency of Vitamin K is not rare [the U.S. has an unnatural aversion to leafy
green vegetables, unlike most other countries; we are the ones who came up with the “meat &
potatoes diet”]. Since the patients, in data I have seen from students in this class, with the
lowest Vitamin K intake (such a 0% AI) were females with at least one child, they have four out of
five risk factors for developing osteoporosis:
2. have had at least one successful pregnancy,
3. will become post-menopausal, and
4. have possible sub-clinical deficiency of Vitamin K.
5. [We will look at the fifth risk factor (calcium intake) in the lecture on Minerals].
Do you think such patients might benefit from increasing their Vitamin K intake?
Another issue you must consider in assessing your patient's diet is overdosing. For example, if your patient has a high intake (such as 230% RDA) of Vitamin E [another number from student submitted data for this class], we need to find Vitamin E (pg. 20-8 & 20-9), and read column 4 (pg. 20-9) to get the consequences of overdose. In this case, Vitamin E overdosing may lead to increased blood clotting time. If such a patient were on prescription anticoagulants (due to plaque-related arterial blockage, and possibily diagnosed angina or heart attack), or are taking daily low-dose aspirin to prevent heart disease, the high dose Vitamin E could be a problem.
Having established the potential consequences of under-dosing and/or over-dosing on various nutrients, you will have to triage their dietary issues, and select the two or three issues [you will lose points for selecting more than three, or less than two] that you feel are most important to the patient's wellness. Your report will provide an explanation (rationale) of why you chose the nutritional issues you chose. Your grade will depend on how well you justify your choices, not what you chose [unless, like one former student you address the ‘low carbohydrate’ intake of an overweight patient getting 247% RDA of Calories from carbohydrates; the student lost a full letter grade for this error]. Having identified what you consider to be the two or three most “interesting” issues with the patient's diet, you are to suggest a plan to correct the mistakes. My expectation is that you will recommend specific dietary (food) sources of the nutrients which need to be increased, and specific recommendations for those which need to be decreased [written as if you expect the patient to be compliant, and actually change their eating habits in order to improve their Wellness]. Again, you will be graded on how well you justify your recommendations. If you chose to supplement the patient's diet with food supplements rather than food, your task of defending the recommendation will more difficult due to my bias toward food as the preferred source of nutrition [I believe this bias to be a very poorly kept secret].
Most of the fat-soluble vitamins have overdose symptoms which approach the deficiency symptoms in terms of seriousness of the consequences. For the most part (but check to be sure if the issue arises), the water-soluble vitamins consumed in excess of dietary needs are simply rejected as poisons by the intestines: water is dumped from serum (replaced in serum from interstitial water, leading ultimately to dehydration) into the lumen of the intestines; forward peristolysis is speeded up; and the anal sphincter relaxed -or diarrhea.
There was (and still is) a problem with Vitamin C overdosing. In the 1960's or 70's, the winner of a Nobel prize in Physics [for studies on high energy physics, I think he discovered quarks or something] went on the talk show circuit, and promoted the idea that the common cold could be avoided by taking two daily doses of 1,000 mg Vitamin C tablets per day in addition to dietary Vitamin C from citrus fruits and vegetables [the UL (upper limit) is 2,000 mg]. There are only a few minor problems with this advice: the man was a particle Physicist, not a Medical Doctor, but was giving medical advice; the ‘data’ in support of the claims (Vitamin C prevents the common cold) are misinterpreted examples of the placebo effect; and many people taking this advice developed chronic low-grade diarrhea, yet continued overdosing on Vitamin C in tablet form. The mythology of Vitamin C as preventing the common cold [the “common cold” is not even a recognized disease, but is a sydrome, or group of signs and symptoms, known to be associated with at least 3,000 bacterial and viral infections] persists in the general population; the clinical studies have suggested (not confirmed) that Vitamin C at 100% to 200% RDA may decrease the duration and severity of the common cold, but not the frequency of catching a cold. Because there are recurrent fads involving unusually high doses of different vitamin supplements on the presumption that unbelievable claims might be true, it is necessary to point out that megadosing on vitamins is only suitable for theraputic treatment of deficiencies, and then only under continual medical supervision.
I may have mentioned once or twice before, Human physiology is designed by natural selection over 1,000's of generations to acquire nutrients from food. Any nutrient which is in a form which can be absorbed from the lumen of the gut [a technical term for gastrointestinal tract] to the blood serum, and is in a form which can be transported into cells and utilized is called bio-available. The only vitamins which serve as vitamins are bio-available. Vitamins in natural foods are bio-available, because our physiology expects to get nutrients from real food. Some vitamins in supplements that ‘grow’ in chemical processes in factories and mature into “convenient, easily swallowed” tablets are not bio-available and serve primarily to produce enriched fecal material. The original Wonder Bread (the kind that “helps grow strong bodies 12 ways,”) was made from highly processed, bleached wheat flour [from which all nutrients other than carbs had been removed] enriched by 12 different vitamin and mineral supplements which were not bio-available. [I think some of the supplements used to enrich the flour have since been altered to increase bio-availability]
Three of the vitamins have been called anti-oxidants, which appear
(un-confirmed by rigorous scientific testing) to prevent, and even repair damage caused by free
radicals (ionized chemical structures which are proven to break bonds in vital organic
molecules). These are Vitamin C (this is the basis of the myth that Vitamin C prevents the
common cold), Vitamin E, and beta-carotene (a yellow pigment from leafy greens, the darker green in
color) which is a precursor to Vitamin A [and you can convert beta-carotene to Vitamin A]. The part
about repairing damage from free-radicals found its way into the popular press, plus the press
coverage of the French Paradox (next paragraph) led to the development of a cult-like group of
non-science people promoting anti-oxidants [Apparently, the terms “free radical” and
“anti-oxidant” sounded sufficiently 'cool' to make effective slogans].
It is well known that the French diet is not ideal: yet the French seem able to avoid heart disease, and live long, high quality lives. This conflict between “conventional wisdom” and apparent reality has been called the “French Paradox” [which also sounds good when you say it out loud]. The World record, according to the Guiness Book of Records, for life span [age at time of death] was set by a French woman who died at the tender young age of 122 years 5 months. At a press conference in honor of her 120th birthday, she exhibited no signs of age-related dementia (I saw clips from that interview). The runner-up was a French-Canadian woman who died at 115 years 4 months [without signs of age-related dementia]. If you are curious, you can google “Jeanne Louise Calment” (the 122 year old) and “Julie Winnefred Bertrand” (the 115 year old). The French Paradox has been tentatively explained by the anti-oxidants known to be in red wine (of which the French drink a lot). This has been supported by examination of the Japanese diet (rich in anti-oxidants from vegetables which are a major part of the Japanese diet, but not over-cooked) because the Japanese population has one of the highest life expectancies [average age at which 50% of the same-aged population dies] compared to other nationalities.
The popularity of the anti-oxidants led to similar claims for many other plant-derived chemicals [given the catchy name phyto-chemicals]. Phyto-chemicals were heavily promoted by Herbalists. The study of “Folk remedies” from regional plants is one of the legitimate disciplines in Botany. These scientists seek to confirm or discredit the claims of Folk medicine by scientific investigations. They (and Nutritionists plus medical researchers interested in wellness) are currently examining the phytochemicals. Their results thus far have been sufficiently encouraging that the phytochemicals have become credible enough to start appearing in Nutrition textbook and lectures, and are the subject of our next lecture.
TABLE OF CONTENTS
© 2004-2010 TwoOldGuys
revised: 20 Aug 2010