Led by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the new study looked at 2,370 couples who were planning to undergo infertility treatment.
The men were randomly assigned to either a daily supplement, which contained 5 milligrams of folic acid and 30 milligrams of zinc for six months, or a placebo. The women were asked to complete questionnaires from the beginning of the study and for up to 18 months to record their pregnancy outcomes.
The findings, published in the journal JAMA, showed that there was no significant difference in the number of live births between the men who received the supplement (404 births, 34 percent) and the placebo group (416 births, 35 percent).
The two groups of men also had a similar total sperm count and sperm with a similar motility (the ability to move through the female reproductive tract) and shape. However, the researchers did find one difference between the two groups: the men who took the supplements had a statistically significant increase in the amount of broken DNA, known as DNA fragmentation, in their sperm than in the placebo group. The researchers explain that previous studies have suggested that DNA fragmentation can contribute to male infertility.
Moreover, the men who received the supplements also reported experiencing more abdominal pain, nausea, vomiting and other gastrointestinal symptoms than those who received the placebo.
“This is a landmark trial of male infertility supplements,” says James M. Hotaling, M.D., co-author of the study. “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.”
“This large, well-controlled, randomized study shows us that nutraceuticals like zinc and folic acid really don’t improve the chances of a couple getting pregnant and actually can cause side effects that are not beneficial,” added C. Matthew Peterson, M.D., one of the study’s principal investigators. “It’s important for men of all ages to eat a healthy diet to maintain fertility, but you don’t necessarily need to take something extra to help you achieve better sperm parameters.”
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