Half of all Americans routinely take dietary supplements, a $20-billion-a-year market, and multivitamins are the most commonly used, the authors write in the Archives of Internal Medicine.
“People want to take control of their health,” says lead author Marian Neuhouser, an associate member of the Public Health Sciences Division at Seattle’s Fred Hutchinson Cancer Research Center. “Taking a multivitamin kind of empowers people, because they are in charge of that behavior.”
Neuhouser’s study focused on nearly 162,000 postmenopausal women in the government-sponsored Women’s Health Initiative, best-known for hormone therapy research. About four out of 10 said they took multivitamins.
At the end of eight years of follow-up, multivitamin users were just as likely as non-users to have died or been diagnosed with common cancers — those of the breast or lung, to name two — or suffered a heart attack or stroke.
Although the study involved only postmenopausal women, “our findings are consistent with most previously published results,” the authors write.
“Nutritional efforts should remain a principal focus of chronic disease prevention,” they write, but without “definitive results” from a trial in which people are randomly assigned to take a multivitamin or a placebo pill, “multivitamin supplements will not likely play a major role.”
In a statement, Andrew Shao, a vice president at the Council for Responsible Nutrition, a trade group, said, “multivitamins, like all other dietary supplements, are meant to be used as part of an overall healthy lifestyle; they are not intended to be magic bullets that will assure the prevention of chronic diseases like cancer.”
But, says Neuhouser, taking a multivitamin doesn’t make up for a diet lacking in nutrients.