About a third of Americans take a daily multivitamin.
The risk of heart attack and stroke was not cut by taking a daily multivitamin in a study that followed more than 14,500 men for over a decade. There was a small reduction in cancer risk, according to results from the study released in October.
The trial, called the Physicians Health Study II and partly funded by the National Institutes of Health, is the largest to look at health outcomes and multivitamins. The new findings were presented Monday at the American Heart Association annual meeting and published online in the Journal of the American Medical Association.
More than half of Americans take a vitamin or supplement on a regular basis, and about a third take a daily multivitamin.
The study looked at whether taking a common multivitamin—in this casePfizer Inc.’s PFE -1.71% Centrum Silver—can prevent disease compared with taking a placebo or sham vitamin. In addition to cancer and heart disease, researchers also looked at whether multivitamin use affected cognitive decline and eye disease. Information on cognitive decline and eye health has yet to be released. Pfizer provided the vitamins used in the study.
“Many people take vitamins as a crutch,” said Howard Sesso, one of the authors of the study and an associate professor at Harvard Medical School and Brigham and Women’s Hospital, in Boston. “There’s no substitute for a heart-healthy diet and exercise,” he said.
“One thing worth noting is these physicians were quite healthy,” Dr. Sesso added. “A lot of them exercised and most had pretty good diets”—which make it harder to measure the added benefit of a multivitamin.
Many doctors recommend multivitamins, and the supplements are strongly advised for certain groups like pregnant women.
Duffy MacKay, vice president for scientific affairs at the Council for Responsible Nutrition, a Washington, D.C., trade group for supplement makers, says vitamins combined with other “healthy habits” can be a “basic and affordable insurance policy for overall wellness.” He added, “No one should expect the multivitamin to wipe out all diseases known to man.”
The study enrolled 14,641 male U.S. physicians, ages 50 and older when the study began. More than 700 had heart disease at the start. Half received a multivitamin. The other half took placebos that looked like the real vitamins. Vitamins and placebo pills were dispensed in prefilled monthly packages so compliance could be measured.
Researchers followed the participants for more than 11 years, measuring cardiovascular events including heart attack and stroke, and death from a cardiovascular-related cause. There were 1,732 major cardiovascular events and 2,757 deaths during the study.
Researchers said event rates were mostly similar between treatment groups, suggesting multivitamins didn’t influence cardiovascular disease. There were slightly fewer heart attack-related deaths in the vitamin group, which might be attributed to chance, Dr. Sesso said.
Dariush Mozaffarian, associate professor at Harvard School of Public Health and a cardiologist who wasn’t involved in the study, says he worries that many people take vitamins as a “quick fix.” “The danger of taking a multivitamin leads you to think [you] don’t need to do the other lifestyle things that are important,” he said.