Men: Don't Take B Vitamin Supplements
Unless You Understand the Risks vs. Potential Benefits
Jul 20, 2009
Taking supplemental B vitamins had been thought to reduce heart disease, colon cancer, and Alzheimer’s. Unfortunately, studies have not borne out these potential benefits, and now, a study suggests possible harm.
Aspirin/Folate Polyp Prevention Study
Previous studies suggested that both aspirin and folate might lower the risk of colon cancer. A large study followed people who were given aspirin and/or folate supplements, or placebo (as the control group). Most were followed six to eight years, and the results were projected to ten year risk. Neither aspirin nor folate reduced the risk of colon cancer.
Now, investigators looked at data about men in the study. Six hundred forty three men, mean age 57 years at the start of the study, were included. Twenty five cases of prostate cancer occurred in the group taking folate, and only 9 in the placebo group. That meant that taking folate increased the ten year risk of prostate cancer from 3.3% to 9.7%.
“(These results suggest) another reason to advise middle-aged male patients against routine folic acid supplementation,” stated Dr. Allan Brett, Professor of Medicine, University of South Carolina School of Medicine, Columbia. (Journal Watch, April 15, 2009; vol. 29, No.8)
Mg. vs. Mcg.
The men in this study took one milligram (mg) of folate each day. Non-prescription multivitamins usually have 200-400 micrograms (mcg) of folate. A milligram is 1000 micrograms. So these men took about four times more folate each day than is in the usual multivitamin. Researchers postulate that high amount may overdrive nucleotide synthesis needed for cancer cells to get started.
Folate for Coronary Heart Disease
A previous disappointment was the failure of folate to prevent coronary heart disease. Epidemiologic studies have shown that high serum homocysteine levels are associated with more heart disease. Folate can lower homocysteine levels. It had been hoped that lowering homocysteine levels would lower the risk of heart disease. But it didn’t turn out that way. “B Vitamins Fail Test-Folate, Vitamins B-12 and B6 Do Not Prevent Heart Attacks.”
Don’t Give Up On Vitamin Supplements
Women who are or might become pregnant should take folate supplements to prevent neurologic damage to the baby. That is universally accepted. Now, another study suggests benefit for folate supplements: reducing the risk for blindness.
The Women’s Antioxidant and Folic Acid Cardiovascular Study didn’t show benefit from folate to reduce risk of cardiovascular disease or cancer. But a new analysis of data from that research showed that women who took the supplement had less risk of macular degeneration, a leading cause of blindness in older people. After an average of seven years, macular degeneration occurred in two percent of treated women, and three percent in controls. If these results are confirmed in other studies, folate supplementation may offer benefit at least to women. (“Folic acid, pyridoxine, and cyanocobalamin combination treatment and age related macular degeneration.” Archives Internal Medicine 2009, 169: 335)
Vitamin D deficiency can cause weakness, soft bones, and possibly memory problems. A surprisingly large number of people have low blood levels of vitamin D. In one study, one of four men age 65 and older had vitamin D deficiency. And these were men living in the community, i.e., not in nursing homes. It’s easy to make a case for taking non-prescription vitamin D supplements. (“Vitamin D Deficiency in Older Men.” Journal Clinical Endocrinology and Metabolism 2009; 94: 1244.)
Common sense dictates that men with vitamin deficiencies should take vitamin supplements. Men at risk for vitamin deficiency should discuss it with their clinician. But men who are not deficient and contemplate taking supplements solely to prevent heart disease or cancer should consider posible risks as well as possible benefits.
Primary Reference
The Prostate Study is: “Folic acid and risk of prostate cancer: results from a randomized clinical trial.” (Journal National Cancer Institute. 2009 Mar 18;101(6):432-5)
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