Nov. 5, 2012 (Los Angeles) -- Don't count on a vitamin a day to protect you from heart disease. A large, well-designed study shows that men who took daily multivitamins for years did not lower the risk of heart attack, stroke, or death from heart disease.
The study followed nearly 15,000 middle-aged and older men for about 11 years. It is not yet clear if the findings would apply to younger men or women. But a previous study of more than 160,000 women also found that multivitamins did not affect the chance of having heart disease or stroke.
Previous findings from the same study showed that daily multivitamin use reduced the risk of cancer by a modest 8%.
"The main reason to take a daily multivitamin ... remains to prevent vitamin and mineral deficiency,'' says researcher Howard Sesso, ScD, MPH, an epidemiologist at Brigham and Women's Hospital and Harvard Medical School.
"There is no reason to recommend multivitamins for cardiovascular disease. The decision to take a multivitamin should consider its beneficial effects on cancer and other important [health conditions still being] studied," Sesso said at a news briefing at the annual meeting of the American Heart Association here.
Sesso and heart doctors not involved with the study repeatedly said that they fear taking multivitamins lulls people into a false sense of security, distracting them from following proven steps to prevent heart disease.
The Council for Responsible Nutrition (CRN), the leading trade association for the dietary supplement industry, took issue with the doctors' conclusion.
"The opinion that people take a multivitamin in lieu of other healthy habits that can lower heart disease risk is a recurring statement that lacks an evidentiary basis," the CRN says in a statement.
The findings are also published today in the Journal of the American Medical Association.
Previous studies looking at the effect of multivitamin use on heart disease have had mixed results. And large trials of high doses of individual vitamins, such as beta-carotene and vitamin E, have generally shown they do more harm than good.
Despite the lack of solid evidence showing that vitamins and dietary supplements protect against heart disease and many other health conditions, more than half of American adults take at least one supplement, and about 10% take more than five, according to Eva Lonn, MD, of McMaster University in Hamilton, Ontario.
Given their widespread use, their impact on heart disease (the nation's No. 1 killer) is of great importance, says Lonn, who wrote an editorial accompanying the study. In the U.S., heart disease accounted for 1 in 3 deaths in 2008.
The new study is the first large-scale study pitting multivitamins against a placebo in heart disease prevention, Sesso says. Studies like this -- which compare a treatment to placebo or to standard medication, and then follow people over time to see how many in each group develop a disease -- are the gold standard.