A few years back, a study in the New England Journal of Medicine showed that women who supplemented with folic acid reduced the chances of serious birth defects in their offspring. Now the B vitamin appears to have benefits for men, too. Folic acid, together with zinc, improves sperm efficacy in men with fertility problems, according to a study by the University Medical Center Nijmegen in the Netherlands. Both nutrients play key roles in gene function, which researchers theorize might affect semen quality. Also, enzymes that aid testosterone synthesis need zinc, so supplements may stimulate testosterone production, and consequently the volume of sperm. The study, published in the March issue of Fertility and Sterility, involved 108 men whose wives had conceived within a year of intercourse, and 103 men with fertility problems of unknown cause whose wives had failed to become pregnant and whose semen had a sperm concentration of 5 million to 20 million per milliliter. (Fertile men have sperm counts of more than 20 million per milliliter.) Before the study, both groups had similar concentrations of folate and zinc in their blood and seminal fluid. During the 26-week trial, men in both groups followed one of four regimens: daily doses of folic acid and zinc sulfate, folic acid alone, zinc sulfate alone or placebos. The outcome? Men in the fertile group had small increases in sperm count when given folic acid plus zinc or zinc alone, while subfertile men given both supplements showed a 74% increase in sperm count. William Keye Jr., M.D., president of the American Society for Reproductive Medicine, says, “The next step is to see whether the effects of nutritional supplements can result in any increase in pregnancy rates.”