Are Vitamins Killing Us?

Most American’s take supplemental vitamins. Multivitamins, Vitamins A, B, C, D, E, folic acid, calcium and iron contribute to a 60 billion dollar a year alternative medicine industry.  Physicians, lacking data, have long been reticent to recommend vitamin supplements, but have been mute on the safety of these chemicals.  However, a series of frightening studies may end that silence.

In October, the Iowa Women’s Health Study was published in the Archives of Internal Medicine.  In it, 38,772 older women (average 62 years old) underwent close monitoring of their health for 25 years.  Major medical conditions, including heart disease, diabetes and cancer were tracked. General health indicators such as smoking, weight, exercise, diet, alcohol and hormone use were cataloged.  The use of vitamin products was characterized.

Women who took vitamins generally had habits and features associated with better health.  They weighed less, smoked less, exercised more, had less hypertension or diabetes and were better educated.  By the end of the study, the data was clear.  They died sooner.

It depended on the vitamin.  On average, those that took a multivitamin had a 2.4% greater chance of dying.  Iron 3.9%.  Folate 5.9%.  B6 4.1%.  Copper 18%. The only supplement associated with longer life was calcium, which decreased the risk of death by 3.8%. Calcium’s benefit did not increase further above a 1300mg per day dose. (Because this study was in women, it did not address prostate cancer risk, which an earlier trial suggests may increase with high dose calcium).

As if this was not worrisome enough, almost at the same time in The Journal of the American Medical Association comes the SELECT trial.   35,533 men from the United States, Canada and Puerto Rico participated in a study where they received selenium and/or Vitamin E or placebo for seven to twelve years.  During the study 529 men who did not receive Vitamin E developed prostate cancer. The group that took Vitamin E? 620.

These disturbing, well-done, new studies add to the 1995 ATBC Cancer Prevention Study.  Designed to prevent cancer in smokers, this trial found increased lung, prostate or stomach cancer in patients given various combinations of beta-carotene and/or alpha-tocopherol.  These findings were similar to the 2009 Norwegian Vitamin prevention study in smokers. That research found that folate acid plus B12 pills increased cancer rates and death.  The 2008 Cochrane Database review of 26 trials including over 100,000 people, found that Vitamin E alone or combined with vitamin A and beta-carotene, increased the risk of death.

In the past we have had limited high quality research on the health effects of vitamin supplements.  The best studies had shown either no affect or inconsistent results. Now that carefully done research is published, the data leans against taking vitamins. What is most concerning about the studies discussed here is that the goal was to show that vitamins prevent disease.  The researchers hoped there would be benefit, but instead found harm.

What remains?  Research suggests that vitamin D may reduce the risk of colon cancer, especially in those with limited sun exposure. There is apparent benefit of calcium and probably vitamin D on bone health. Folate in young women can prevent neural tube defects in their babies.  Folate in heavy drinkers may decrease certain cancers, although perhaps less alcohol is a better solution.  Though not a vitamin, Omega-3 supplements have a role in those that cannot eat two servings of fatty fish each week.  Medicinal use of vitamins in those that have true deficiencies is vital.

The bottom line, while we await more research, is that the best available studies show that self-medication with vitamins is dangerous.  For tens of thousands of years we have relied on our food to supply the proper balance of nutrients.  Perhaps it is time to get back to those basics.

1 Comment

  • Aw, this was a really quality post. In theory I'd like to write like this too - taking time and real effort to make a good article... but what can I say... I procrastinate alot and never seem to get something done.

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