Though multivitamins have gained popularity year after year, many health professionals have discounted their benefits.
In 2008 Harvard Men's Health Watch, which once endorsed daily dietary supplements, changed its position, saying multivitamins might have some harmful health effects. The following year a study by the Women's Health Initiative suggested money spent on multivitamins was a waste.
False sense of security
Now, researchers in Taiwan say people who take a daily vitamin pill may be more likely to engage in unhealthy behavior. The study was conducted by researchers working for the Dole Nutrition Institute, which advocates a plant-based diet.
In the study, subjects were given placebos. 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. Researchers say the results were astounding.
More hedonistic behavior
The people told they were taking multivitamins registered a 44 percent higher tendency to engage in hedonistic activities, such as casual sex, sunbathing, partying, and binge drinking. When it came to dietary issues, 61 percent showed an increased preference for all-you-can-eat buffets over healthy meals.
Compared to the placebo group, the "multivitamin" group not only reported exercising 14 percent less, they were 66 percent more likely to walk the shortest distance to their goal over a given time.
The authors of the study 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. Then there's the financial price; consumers spend about $27 billion a year on multivitamins.
Lack of evidence
With regard to direct health impact, a "state-of-the-science" National Institutes of Health (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, in recent years, has backed away from vitamins and now urges people to forgo antioxidant supplements in favor of fruit and vegetables to minimize cardiovascular disease risk.