According to a new study, taking a multivitamin does not help you reduce your risk of developing cancer, or heart disease. Combination pills, which contain 10 to 30 vitamins and minerals, are the most popular dietary supplements sold in America. A report published today in the Archives of Internal Medicine suggests they shouldn’t be.

The research examined 161,808 women, age 50 to 79, who took part in clinical trials on hormone therapy, dietary modification and vitamin D supplements, as well as 93,676 women who were part of an observational study.

In a news release, researcher Marian Neuhouser, PhD, says that it was a "surprise" to find that "multivitamins did not lower the risk of the most common cancers and also had no impact on heart disease."

After controlling for age, physical activity, family history of cancer and many other factors, the researchers found that the supplements had no effect on the risk for breast cancer, colorectal cancer, endometrial cancer, lung cancer, ovarian cancer, heart attack, stroke, blood clots or mortality.

Moreover the annualized percentages of cardiovascular disease were lower among women taking multivitamins, but they were not significantly different from the percentages in those not taking vitamins, the researchers said. They also found no association between the length of time a woman used multivitamins and her risk of cancer or cardiovascular disease.
Some physicians continue to recommend multivitamins as a backstop for patients whose diets may contain nutritional gaps. And since they don’t require a prescription, many people simply assume they are safe.

The new findings were published in the February issue of The Archives of Internal Medicine. The researchers said their study may have been limited since the Women's Health Initiative evaluated only postmenopausal women, so the results may not be generalizable.