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SKEPTOID BLOG:

The Latest Vitamin Uproar

by Guy McCardle

October 15, 2011

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Donate Vitamins are big business. Sales topped $9.6 billion in the US alone last year. Millions of us take them, but do they really do any good? More importantly, could they be causing us harm? No US government agency recommends them "regardless of the quality of a person's diet," says a fact sheet from the federal Office of Dietary Supplements. According to a report in the October 10 issue of Archives of Internal Medicine, consuming dietary supplements, including multivitamins, folic acid, iron and copper, among others, appears to be associated with an increased risk of death in older women.

Jaakko Mursu, Ph.D., of the University of Eastern Finland, and the University of Minnesota, Minneapolis, and colleagues used data collected during the Iowa Women's Health Study to examine the association between vitamin and mineral supplements and mortality (death) rate among 38,772 older women (average age 61.6 years). Supplement use was self-reported in 1986, 1997 and 2004 via questionnaires. As expected, they found that the use of dietary supplements in the United States has increased considerably over the last decade. This corresponds to the increase in age of the baby boomer generation.

Among the 38,772 women who started follow-up with the first survey in 1986, 15,594 deaths (40.2 percent) occurred over an average follow-up time of 19 years. Self-reported supplement use increased substantially between 1986 and 2004, with 62.7 percent of women reporting use of at least one supplement daily in 1986, 75.1 percent in 1997 and 85.1 percent in 2004.

The researchers found that use of multivitamins, vitamin B6, folic acid, iron, magnesium, zinc and copper, were all associated with increased risk of death in the study population. Conversely, calcium supplements appear to reduce risk of mortality. The association between supplement intake and mortality risk was strongest with iron, and the authors found a dose-response relationship as increased risk of mortality was seen at progressively lower doses as women aged throughout the study. Findings for both iron and calcium supplements were replicated in separate, short-term analyses with follow-up occurring at four years, six years and 10 years.

"Based on existing evidence, we see little justification for the general and widespread use of dietary supplements," the authors conclude. "We recommend that they be used with strong medically based cause, such as symptomatic nutrient deficiency disease."

It is not only women who have been found to be susceptible to adverse effects of certain vitamins. Another recent study, appearing in the Oct. 12, 2011 issue of the Journal of the American Medical Association, showed that men who took 400 international units (I.U.) of vitamin E daily had more prostate cancers compared to men who took a placebo. Data for the study was collected as a part of the Selenium and Vitamin E Cancer Prevention Trial (SELECT). The findings showed that, per 1,000 men, there were 76 prostate cancers in men who took only vitamin E supplements, vs. 65 in men on placebo over a seven-year period, or 11 more cases of prostate cancer per 1,000 men. This represents a 17 percent increase in prostate cancers relative to those who took a placebo. This difference was statistically significant and therefore is not likely due to chance.

"Based on these results and the results of large cardiovascular studies using vitamin E, there is no reason for men in the general population to take the dose of vitamin E used in SELECT as the supplements have shown no benefit and some very real risks," said Eric Klein, M.D., a study co-chair for SELECT, and a physician at the Cleveland Clinic.

Over the past few years, dietary supplementation has shifted from preventing deficiency to trying to promote wellness and prevent disease. The FDA does not evaluate these claims. Do most people even need vitamin supplements (the industry calls them an insurance policy against bad eating) in the first place? Probably not. Our foods are increasingly pumped full of vitamins already. Even junk foods and energy drinks often are fortified with nutrients to give them a healthier profile, so the risk is rising that we're getting too much. Add a supplement and you may exceed the upper limit. Regarding vitamins, David Schardt, a nutritionist at the consumer group Center for Science in the Public Interest states, "We're finding out they're not as harmless as the industry might have us believe".

Does all of this mean you should rush out and throw away all of your old vitamins immediately? Well, that's your choice. I'd recommend consulting a physician before making any changes. Today we have learned some additional information to put into our "tool box of science", if you will. As adults, we have the right to make the best decisions for ourselves based on the latest available information. Knowledge is power. Choose wisely.

by Guy McCardle

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