The lack of evidence on multivitamin health benefits is no impediment to their widespread popularity, with over half the U.S. population popping such pills. This translates into a $27 billion industry, which lures consumers with the illusory promise of better health. But shocking new research suggests taking multivitamins might have the opposite effect -- not simply on the metabolic level, but on a metaphysical one: promoting a false sense of invulnerability that actually leads users to engage in riskier behaviors.
Taiwanese researchers conducted an experiment in which they gave placebos to 82 adults (45 women, 37 men, average age 31). Half of this group was led to believe that the placebo they were taking was a multivitamin. After one week, all participants took surveys regarding their inclinations towards various healthy vs. less healthy behaviors. The results were astounding. Those subjects thinking they were taking multivitamins registered a 44% higher tendency to engage in hedonistic activities (e.g., casual sex, sunbathing, partying, binge drinking), as well as a 61% increased preference for all-you-can-eat buffets over healthy meals. Compared to the placebo group, the "multivitamin" group not only reported exercising 14% less, they were 66% more likely to walk the shortest distance to their goal over a given time.
The authors conclude that people relying on a multivitamin pay a hidden price, believing they have greater invulnerability and so adopt lazy, riskier behaviors that may actually lead to the exact opposite health outcomes they desire. With regard to direct health impact, a "state-of-the-science" NIH panel found insufficient evidence to recommend multivitamin usage, while the National Cancer Institute actually found that men who take more than seven multivitamins a week are a third more likely to experience advanced prostate cancer. The American Heart Association urges people to forgo antioxidant supplements in favor of fruit and vegetables to minimize cardiovascular disease risk.
Antioxidant pills may even block certain metabolic benefits of exercise.
In a recent German study, 40 young male volunteers engaged in about an hour and a half of intense exercise -- running, cycling, weight-lifting -- five days a week.As expected, the regimen yielded various health benefits, including improved ability to control blood sugar, thus reducing diabetes risk.But when the men took antioxidant supplements -- 400 IU of vitamin E and 1,000 mg of vitamin C -- there was NO improvement in insulin sensitivity.Why? The pills seem to displace the body's own natural antioxidant systems, which otherwise neutralize the oxidative damage caused by oxygen radicals produced during exercise.
These findings add to the mountain of evidence that reliance on supplements either offers no benefits or even poses specific health risks. For example, athletes and others take glucosamine to relieve joint pain, but research shows most commercial supplements are ineffective, while the safety of large doses remains uncertain