Should you pop a multivitamin to protect yourself against cancer? Previous studies found no such protection from daily multivitamin supplements, but newer studies have yielded differing results.

The large-scale Physicians' Health Study-II, which followed nearly 15,000 men for an average of eight years, found that vitamin E and vitamin C supplements did not reduce their risk of prostate or total cancer. The Women's Health Study, which evaluated nearly 40,000 female health professionals over 10 years, found no cancer-protection benefit from taking vitamin E.

In the Women's Antioxidant and Folic Acid Cardiovascular Study, more than 5,000 women assigned to B vitamin supplements had no significant protection against total invasive cancer or breast cancer. (Though recent studies have found potential cancer benefits from taking multivitamins.)

Protection in older women with breast cancer

A new study, published in October 2013 in Breast Cancer Research and Treatment, found that multivitamin/mineral supplements may help older women who develop invasive breast cancer survive their disease, according to researchers from Albert Einstein College of Medicine (New York City).

Using data on more than 161,000 postmenopausal women in the Women's Health Initiative Clinical Trials and the Women's Health Initiative Observational Study, the study focused on women who were diagnosed with invasive breast cancer (cancer which has spread outside the milk glands and ducts into the breast tissue) and who were followed for an average of seven years.

About 38 percent of women took multivitamin/mineral supplements, and the women who took these supplements were 30 percent less likely to die from their cancers than women who did not take them.

Modest protection from cancer in older men

A recent Harvard study, published in the Journal of the American Medical Association in October 2012, linked multivitamin use with cancer protection in older men. The study, which followed nearly 15,000 middle-aged and older men for about 11 years, found that those who took a daily multivitamin had an 8 percent reduction in total cancer risk.

The bottom line on multis

Some experts report that these results may be skewed, as people who take supplements tend to be healthier--although researchers in both studies did their best to control for healthy behaviors in their analysis. It may be that there is a protective effect from taking multivitamin/mineral supplements, which generally contain 20 or more vitamins and minerals, usually at the Recommended Dietary Allowance (RDA) level, which may boost general health.

If you choose to take a multivitamin, purchase one from a reliable manufacturer and make sure that it does not exceed 100 percent of the RDA for any nutrient.

(Reprinted with permission from Environmental Nutrition, a monthly publication of Belvoir Media Group, LLC. 800-829-5384. http://www.EnvironmentalNutrition.com.)

(c) 2014 BELVOIR MEDIA GROUP DISTRIBUTED BY TRIBUNE CONTENT AGENCY, LLC.