Zinc and folic acid, a pair of dietary supplements long touted as an effective treatment for male infertility, failed to improve pregnancy rates, sperm counts and sperm potency in a new study conducted at University of Utah Health and other medical centers in conjunction with the National Institutes of Health, published in JAMA.
“This is a landmark trial of male infertility supplements,” says James M. Hotaling, M.D., co-author of the study and a U of U Health urologist specializing in male infertility. “The take-home message for men is that, for the first time, there is high-quality data that zinc and folic acid do not improve live birth outcomes or semen function.”
Many fertility supplements contain zinc, a mineral essential for sperm development, and folate, the natural form of folic acid that helps form DNA in the sperm. These over-the-counter supplements, also known as nutraceuticals, are often promoted as a natural way to enhance sperm formation, sperm count, and movement. However, previous studies of these products have produced inconclusive results.
For this study, the researchers recruited 2,370 couples planning to undergo infertility treatments in Salt Lake City, Chicago, Minneapolis, and Iowa City, Iowa. Men were randomly assigned to either receive a placebo or a daily supplement consisting of 5 milligrams of folic acid and 30 milligrams of zinc for six months.
Researchers found no significant differences in live births between the men who received the supplement (404 births, 34%) and the placebo group (416 births, 35%). Men in the two groups also had similar measures for total sperm count, mobility, and shape. Men in the supplement group complained of more abdominal pain, nausea, vomiting, and other gastrointestinal symptoms than those in the placebo group.