Taking a daily multivitamin has become a symbol of taking care of yourself, of showing you’re serious about good health. Where did this idea come from and is there any evidence supporting it?

Food Pyramid

This idea of adults swallowing vitamin pills took hold in the 1980’s whenlab and animal studies suggested that antioxidants (vitamin E, vitamin C, vitamin A, and beta carotene) might protect against cancer, colds, coronary disease. Before clinical trials were begun, everyone started popping them, asking only: at what age do I start? And how many do I take? In 1994, Congress removed “dietary supplements” from the jurisdiction of the FDA, opening the way for manufacturers to pile on wild and undocumented health claims. Sales quintupled, producing a $30 billion industry. 

Then the boom went bust. Human studies demonstrated that antioxidants might do more harm than good. Beta carotene seemed to increase the risk of lung cancer in male smokers; excess amounts of vitamin A are linked to an increased risk of fractures. So the next cluster of hopefuls stepped forward, the B vitamins--B₆, B₁₂, and folic acid—promoted as cardioprotective. But in clinical trials, the three B’s disappointed as well.

The vitaministas prepared their defenses: the populations involved in the trials were limited, the doses tested were wrong, the whole idea of studying one vitamin (or just a few) at a time, focusing on one disease at a time was tunnel-visioned. Then in 2006, the NIH reviewed the use of daily multivitamin/mineral supplements for the prevention of cancer and chronic disease in randomized clinical trials and concluded that “the strength of evidence is insufficient to support the presence or absence of a benefit from routine use of multivitamin and mineral supplements by adults in the United States for primary prevention of cancer, cardiovascular disease, hypertension, cataracts, or age-related macular degeneration.” This was followed in 2008 by results from the Women’s Health Initiative, the largest study with the longest follow-up, providing convincing evidence that multivitamin use has little or no influence on common cancers, cardiovascular disease or total mortality in postmenopausal women

If you ask the nutritional gurus of the moment they vociferously recommend a diet rich in fruits, vegetables, whole grains, nuts and healthy oils, which the multivitamin can never healthily replace. But if you ask them what extrasthey take in 2010, nearly every one answers: a multivitamin. (Some also suggest cocktails of other supplements such coenzyme Q10, magnesium). The multivitamin is the sine qua non, the final pill left standing, but for no good scientific reason.Calcium andVitamin D, required for bone health and which may lower the risk of colon and breast cancer, is not even included in standard multivitamins and requires an extra pill. 

So what is going on here? The generic multivitamin is inexpensive, and probably not harmful (at least there’s no evidence yet), and it provides “insurance” against deficiencies that are only imagined by well-fed, generally healthy folks. There are individuals who really should take a multivitamin (the subject of a future blog), but most Americans who take one every day are doing so for undocumented benefits, with some false and seductive belief in the quick fix.  The multivitamin these days is really just a hunch, a totem, and a symbol of healthy living.