Multivitamins Reduce Cancer Rates

CHICAGOTaking a multivitamin daily for more than a decade reduced cancer rates in a study of 15,000 men (JAMA 2012;308(18). DOI:10.1001/jama.2012.14641). Researchers at Brigham and Womens Hospital and Harvard Medical School found men taking a multivitamin had an 8-percent reduction in total cancer incidence.

Although the main reason to take multivitamins is to prevent nutritional deficiency, these data provide support for the potential use of multivitamin supplements in the prevention of cancer in middle-aged and older men," the researchers concluded.

Researchers analyzed data from the Physicians Health Study (PHS) II, the only large-scale, randomized, double blind, placebo-controlled trial testing the long-term effects of a common multivitamin in the prevention of chronic disease. The trial of 14,641 male U.S. physicians older than 50 included 1,312 men with a history of cancer. Beginning in 1997 and with treatment and follow-up through June 1, 2011, the men either received a daily multivitamin (as Centrum Silver from Pfizer Consumer Healthcare) or a placebo.

During a median follow-up of 11.2 years, 2,669 men were diagnosed with cancer, including 1,373 cases of prostate cancer and 210 cases of colorectal cancer. Some men experienced multiple events. A total of 2,757 (18.8 percent) men died during follow-up, including 859 (5.9 percent) due to cancer.

Compared with placebo, men taking a daily multivitamin had a statistically significant reduction in the incidence of total cancer (multivitamin and placebo groups, 17.0 and 18.3 events, respectively, per 1,000 person-years; P=0.04).  Men taking a multivitamin had a similar reduction in total epithelial cell cancer.

Daily multivitamin use was associated with a reduction in total cancer among the 1,312 men with a baseline history of cancer (P=0.02), but this did not differ significantly from that among 13,329 men initially without cancer (P=0.15).

Approximately half of all incident cancers were prostate cancer, many of which were early stage. The study found no significant effect of a daily multivitamin on prostate cancer (multivitamin and placebo groups, 9.1 and 9.2 events, respectively, per 1,000 person-years; P=0.76), colorectal cancer (multivitamin and placebo groups, 1.2 and 1.4 events, respectively, per 1,000 person years; P=0.39), or other site-specific cancers, including colorectal, lung and bladder cancer. The researchers also found no significant difference in the risk of cancer mortality (multivitamin and placebo groups, 4.9 and 5.6 events, respectively, per 1,000 person-years; P=0.07).

The high level of prostate cancer incidence may have been due to  increased surveillance for prostate-specific antigen (PSA) and subsequent diagnoses of prostate cancer starting in the late 1990s. Most of the prostate cancer in this study was in the early states and a type of cancer that has high survival rate. "The significant reduction in total cancer minus prostate cancer suggests that daily multivitamin use may have a greater benefit on more clinically relevant cancer diagnoses," the study authors wrote.

This study reinforces the value of long-term consistent use of a daily multivitamin as a convenient and affordable insurance policy for good health, said Duffy MacKay, N.D.,  vice president, scientific and regulatory affairs, Council for Responsible Nutrition (CRN), a trade organization for the dietary supplement industry.  Whether or not this study can be generalized to the total population is not answered by this study; however, there are other well-researched benefits for the multivitamin in the general population.

This positive multivitamin news comes a day after a study found high-dose multivitamins didn't improve outcomes for HIV patients receiving antiretroviral therapy. However, previous studies have shown supplementation with a multivitamin improved memory in older men at risk for cognitive decline, and a daily multivitamin increased height, lowered anemia risk, and reduced diarrhea and fever incidences in undernourished children.

MacKay added that women of child-bearing age are regularly advised to take a multivitamin with 400 mcg of folic acid to help prevent certain birth defects such as spina bifida.