Bronze-level articleVitamin supplement

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A supplement advertisement that offers to Help with Everything that Ails.
Note: This information applies to adults. Children should not be given any medications or supplements not recommended by their doctor, and should take all medications recommended by their doctor. The main purpose of the article is to separate vitamin myth from fact, not to give medical advice.

Vitamin supplements are vitamins sold with specific health claims beyond their usual physiologic function. Vitamins are micronutrients which are required in very small amounts for specific physiologic processes. Since their discovery, there has been great interest in using vitamins not just to treat deficiency diseases but also for medicinal purposes. Like everything else in natural/holistic health, the claims run the gamut in factual, scientific efficacy. A few claims are backed by scientific study, most claims have been simple salesmanship, and a few have been irresponsibly, dangerously extravagant.

Contents

[edit] Vitamin industry

The dietary supplement industry is quite large, and the biggest part of the industry is vitamin sales. Numbers are difficult to come by, as they are compiled and sold by marketing firms, but best estimates place sales at over five billion dollars annually.[1][2] There is much misinformation about the benefits of vitamins. This article will strive to help people make better decisions about vitamin supplementation, and help to sort out extravagant claims made by producers and marketers of vitamins.

Extravagant Claims, and a Free Gift!

[edit] Claims

Because of the great interest in vitamins as medications, a great deal of research has gone into investigating their safety and efficacy. However, in the US, vitamins are regulated as dietary supplements, not medications, and there are no requirement for manufacturers to prove efficacy. By definition, vitamins are needed for health. In most cases, a basic, inexpensive, "general multivitamin supplement" is sufficient for adults to remain healthy. However, there is a growing body of evidence that multivitamins are unnecessary for those without vitamin deficiencies and could even cause harm in some isolated cases.[3][4] Additionally, they are often marketed for uses far beyond their basic function and in much higher doses than typically needed.

The health claims used on the bottles are intentionally vague and non-specific (phrases such as "helps support", "promotes", or "bolsters"). With further protection from the Quack Miranda Warning, non-specific ailments can be treated in non-specific ways with non-specific results.

[edit] Efficacy and safety

High dose anti-oxidant pills appear to be worse than useless. Yes, that's right, anti-oxidants hinder muscle strength. This appears to be because muscles require a certain level of oxidative stress in order to build over time.[5]

[edit] Vitamin A/beta carotene

Vitamin A deficiencies can occur in developing nations and can lead to severe visual problems, and other conditions. Beta carotene, a common precursor to Vitamin A used as a supplement, has been studied as an "anti-oxidant" and cancer preventative. However, large, well-conducted studies have shown an increase in lung cancer in people taking these supplements. Smokers, and others at increased risk for lung cancer, saw their risk increase even more.[6] Also, a recent study showed an increase in aggressive prostate cancers in men taking beta carotene.[7]

Since Vitamin A derives from beta carotene, a carotenoid[wp] pigment, massive overdoses of either substances can turn the consumer's skin yellow or orange. Also, both substances are closely related to retinoid[wp] pigments such as form the photosensitive component of most animal eyes. Such substances are also used in medicine to treat severe skin diseases such as disfiguring acne and ichthyosis; however, they can be teratogens[wp] due to their effect on DNA, requiring careful monitoring, especially in female patients.

Unlike beta carotene, vitamin A in retinoid form is not water soluble. Thus, serious health complications can arise from taking too much of it (c.f. Hypervitaminosis A[wp]). This is why you shouldn't eat polar bear liver.

[edit] B-vitamins

  • Vitamin B9, more commonly known as "folic acid," has been shown in several large well-controlled studies in the U.S. and China to prevent neural tube defects like spina bifida. The effect was greatest when women began taking folic acid before becoming pregnant. This has led to folate supplementation of foods in the U.S.[8] High homocysteine levels in adults is associated with heart disease, and can be reduced by adequate folate intake,[9] although it has not been shown that taking folic acid reduces cardiac risk.
  • A deficiency of Vitamin B1, called "thiamine", can result in beri beri.
  • A deficiency of Vitamin B2, called "riboflavin", can result in ariboflavinosis. However, riboflavin deficiency is always accompanied by deficiency of other vitamins.[10]
  • A deficiency of Vitamin B3, called "niacin", can result in pellagra. Although the U.S. RDA of niacin is 20 mg per day, niacin is increasingly being prescribed at therapeutic dosage levels (upwards of 1000 mg per day) as a treatment for elevated blood triglycerides. Unfortunately, large doses of niacin can result in uncomfortable flushing episiodes; these can be managed by taking aspirin half an hour before taking niacin or sometimes by just eating a meal first. "No flush" versions of niacin exist, but these have been demonstrated not to have an effect on blood triglycerides and thus kinda defeat their own purpose.
  • Vitamin B12 deficiency, usually from certain intestinal diseases or pernicious anemia, is fairly rare, and when it exists, it must be treated. Supplementing this vitamin in non-deficient people has not shown to have any benefit, but oral supplementation as part of a daily multivitamin may have a small effect of reducing cardiac risk in some people.[11]
  • Folate, B12, and B6 are sometimes recommended for memory, but studies have failed to show any benefit in non-deficient individuals.[12]
  • Vitamin B6 very rarely requires supplementation in the typical American diet.[13]

[edit] Vitamin C

Vitamin C may have the most notoriety of the commonly available vitamin supplements due to Nobel Prize-winning biochemist Linus Pauling's controversial assertions that large doses of vitamin C can prevent the common cold, a position that a) showed that even Nobel Prize winners can be wrong, egregiously wrong (see also Brian Josephson, William Shockley, and Egas Moniz) and b) proved to be not terribly accurate when studied, but very persistent in the journals of public opinion probably due to a lack of peer review in that forum.

In addition to its usual function of preventing scurvy, vitamin C is also used as a preservative for fresh fruit (especially apples, where it prevents enzymatic browning after the fruit is cut). In addition, food scientist and cookbook author Shirley Corriher, in her 1997 kitchen science book Foodwise, recommends adding vitamin C to some bread recipes to enhance gluten development.

Like Vitamin E and Beta Carotene, Vitamin C is an antioxidant.

[edit] Vitamin D

See the main article on this topic: Vitamin D

Vitamin D is especially important for bones. There is evidence that people who live in cooler, cloudier climates, where sun exposure is less, benefit from some supplementation.[14]

[edit] Vitamin E

According to the first edition of Harold McGee's seminal kitchen-science book On Food and Cooking, Vitamin E deficiencies are not especially common in the Western diet. However, supplements are sold and sometimes used as skin care lotions. Vitamin E is also sometimes used as a preservative for whole grain products.

Note: "… researchers from the Cleveland Clinic found that men who took vitamin E had an increased risk of prostate cancer."[15]

Like Vitamin C and Beta Carotene, Vitamin E is an antioxidant.

[edit] Vitamin K

Vitamin K (from the German Koagulationsvitamin) is used in the human body's blood clotting system and is not widely available as a supplement. It is contra-indicated for those on anti-coagulant therapy (Warfarin) and is useful in the treatment of ingestion of rat poison (Warfarin).

[edit] Minerals

Dietary minerals, such as phosphorus, magnesium, zinc, and kryptoniteDo You Believe That?, aren't classified as vitamins. However, many multivitamin supplements also include some minerals.

Several snake oil salesmen over the years have pushed mineral supplements. Sales pitches such as Dead Doctors Don't Lie, colloidal silver, and more recently, Miracle Mineral Supplement, tout their mineral supplements as the cure for everything from aging to prostate cancer. Generally these high-priced mineral supplements are in some form you can't get from your local drugstore, such as colloidal suspensions, accompanied by claims that their form is much better absorbed than the normal pills are. At best, these mineral supplements will give you very expensive urine. At worst, they can cause serious side effects in sufficient quantities.

[edit] Pseudovitamins

A number of substances are sold claiming to be vitamins but are not. See pseudovitamin for a list. These are often named using the "vitamin" naming convention, as in "Vitamin B17" (which is actually laetrile). A number of other substances were also once thought to be vitamins but later reclassified out of the vitamin category; occasionally one will run across these still being referred to using their old (generally pre-World War II) vitamin name, such as "Vitamin F" and "Vitamin B4". "Vitamin F" was the old name for essential fatty acids, which are essential for human nutrition but do not meet the definition of a vitamin any more than water does. "Vitamin B4/sub>" is adenine, which is no longer considered a vitamin as it is not necessary for human nutrition, although it is synthesized in the body and binds with other B complex vitamins. Taking any of these supplements is a waste of money, and in the case of "B17"/laetrile, can be hazardous to your health.

[edit] National bans on vitamin supplements

Denmark bans the sale of products with excessive amounts of vitamins, believing them to be a health risk.[16]

[edit] Resources

If you need to take a vitamin supplement it's worth remembering that there are degrees of how good a product is. So, always err on the side of caution. With that in mind, the following is a list of websites which monitor the quality of supplements (including vitamin supplements) and the claims of their makers.

  • Medline Database: www.nlm.nih.gov/medlineplus/
  • Consumer Lab: www.consumerlab.com
  • The American Journal of Clinical Nutrition: www.ajcn.org
  • Supplement Watch: www.supplementwatch.com
  • Food and Drug Administration: www.cfsan.fda.gov
  • Institute of Food Technologies: www.ift.org
  • National Institutes of Health, Office of Dietary Supplements: www.ods.od.nih.gov

[edit] See also

[edit] Footnotes

  1. http://www.bulkmsm.com/convention/C/p7.htm
  2. http://www.usatoday.com/news/health/2006-05-17-multivitamins_x.htm
  3. http://www.sciencebasedmedicine.org/more-evidence-that-routine-multivitamin-use-should-be-avoided/
  4. http://www.npr.org/blogs/health/2013/12/17/251955878/the-case-against-multivitamins-grows-stronger
  5. For athletes, antioxidant pills may not help performance: Some supplements can blunt the positive effects of exercise training by Laura Beil, Science News (February 24, 2015).
  6. Gilbert S. Omenn, Gary E. Goodman, Mark D. Thornquist, John Balmes, Mark R. Cullen, Andrew Glass, James P. Keogh, Frank L. Meyskens, Jr., Barbara Valanis, James H. Williams, Jr., Scott Barnhart, Martin G. Cherniack, Carl Andrew Brodkin, Samuel Hammar. Risk Factors for Lung Cancer and for Intervention Effects in CARET, the Beta-Carotene and Retinol Efficacy Trial. JNCI Journal of the National Cancer Institute 1996 88(21):1550-1559.
  7. Ulrike Peters, Michael F. Leitzmann, Nilanjan Chatterjee, Yinghui Wang, Demetrius Albanes, Edward P. Gelmann, Marlin D. Friesen, Elio Riboli, and Richard B. Hayes. Serum Lycopene, Other Carotenoids, and Prostate Cancer Risk: a Nested Case-Control Study in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Cancer Epidemiol Biomarkers Prev 2007 16: 962-968 doi: 10.1158/1055-9965.EPI-06-0861
  8. http://www.cdc.gov/mmwr/preview/mmwrhtml/00039032.htm
  9. Welch GN, Loscalzo J. Homocysteine and atherothrombosis. N Engl J Med 1998;338:1042-1050.
  10. Brody, Tom (1999). Nutritional Biochemistry. San Diego: Academic Press. ISBN 0-12-134836-9. OCLC 212425693 39699995 51091036 162571066 212425693 39699995 51091036. 
  11. Selhub J, Jacques PF, Wilson PWF, Rush D, Rosenberg IH. Vitamin status and intake as primary determinants of homocysteinemia in an elderly population. JAMA 1993;270:2693-2698
  12. Balk EM. Raman G. Tatsioni A. Chung M. Lau J. Rosenberg IH. Vitamin B6, B12 and folic acid supplementation and cognitive function: a systematic review of randomized trials. Archives of Internal Medicine. 167(1):21-30, 2007 Jan 8.
  13. What Vitamins Should I Be Taking, Doctor? Willett WC, Stampfer MJ. N Engl J Med 345:1819, December 20, 2001.
  14. Thomas MK, Lloyd-Jones DM, Thadhani RI, et al. Hypovitaminosis D in medical inpatients. N Engl J Med 1998;338:777-783.
  15. http://my.clevelandclinic.org/media_relations/library/2011/2011-10-11-national-study-finds-vitamin-e-supplement-may-increase-prostate-cancer-risk.aspx
  16. http://www.nytimes.com/2011/06/17/world/europe/17copenhagen.html?_r=1&
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