Folic acid and zinc supplements not helpful in infertility treatments, nor do they boost sperm count: Study

The findings do not support the use of folic acid and zinc supplementation by male partners for the treatment of infertility, say researchers.


                            Folic acid and zinc supplements not helpful in infertility treatments, nor do they boost sperm count: Study
Most supplements for male fertility contain folic acid and zinc, says the research team. (Getty Images)

Among couples who opt for infertility treatments, the use of folic acid and zinc supplements by male partners does not significantly improve couples’ live birth rates or semen quality of the male. The new findings of a clinical trial do not support the use of folic acid and zinc supplementation by men in the treatment of infertility, say researchers. The global dietary supplement market is projected to exceed $200 billion in the early 2020s. In the US, an estimated 45% of adult men used dietary supplements from 1999 to 2012, and supplement use is common in men among couples trying to have a child. 

“Many formulations claim benefits for fertility ranging from sperm count and motility to libido and vitality. However, the US Food and Drug Administration (FDA) is not permitted to evaluate dietary supplements until aftermarket, contributing to a largely unregulated industry of products with unproven safety and efficacy,” says the research team from Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland; University of Utah, Salt Lake City; and University of Iowa, Iowa City, among others.  

Dietary supplements marketed for male fertility commonly contain folic acid and zinc-based on limited prior evidence for improving semen quality. A 2002 study, for example, said that total normal sperm count increases after combined zinc sulfate and folic acid treatment in both subfertile and fertile men.

According to the researchers of the current study, no large-scale trial has examined the efficacy of this therapy for improving semen quality or live birth, until now.

Dietary supplements marketed for male fertility commonly contain folic acid and zinc-based on limited prior evidence for improving semen quality, says the research team. (Getty Images)

In the current study, published in JAMA, researchers examined the effect of daily folic acid and zinc supplementation on semen quality and live birth.

Male partners of couples planning infertility treatment were enrolled at four US reproductive endocrinology and infertility care study centers, located in Salt Lake City, Utah; Iowa City, Iowa; Chicago, Illinois; and Minneapolis, Minnesota. Men were instructed to stop taking dietary supplements containing folic acid or zinc, as well as medications known to interact with folic acid or zinc. Trial recruitment occurred between June 2013 and December 2017 and 2,370 men were randomized: 1,185 to the folic acid and zinc group and 1,185 to the placebo group. They were either given 5 mg of folic acid and 30 mg of elemental zinc, or placebo daily for 6 months.

According to the analysis, there were 820 live births, which did not significantly differ between the two groups: 404 (34%) in the folic acid and zinc group versus 416 (35%) in the placebo group.

Effect of folic acid and zinc supplementation in men on semen quality and live birth. (JAMA)

“Among a general population of couples seeking infertility treatment, the use of folic acid and zinc supplementation by male partners, compared with placebo, did not significantly improve semen quality or couples’ live birth rates. For the semen quality parameters, sperm concentration, motility, morphology, volume, and total motile sperm count were not significantly different after 6 months,” says the study.

It adds: "Gastrointestinal symptoms were more common with folic acid and zinc supplementation compared with placebo (abdominal discomfort or pain: 66 versus 40 respectively; nausea: 50 versus 24; and vomiting: 32 versus 17."

A 2019 study of dietary supplements marketed as fertility aids for women found that there is no evidence that they help women become pregnant. 

For the study, the Center for Science in the Public Interest (CSPI) identified 39 women’s fertility supplements -- containing a total of 94 different ingredients -- manufactured by 27 companies. The manufacturers claimed that the products are intended for women who have had difficulty conceiving or who have underlying health conditions that put them at risk of infertility.

“Not a single manufacturer of any of the 39 products identified by CSPI provided any reasonable scientific substantiation that its products help women become pregnant," said CSPI in a statement. Based on their findings, the non-profit group asked FDA and the Federal Trade Commission to take action against these manufacturers for marketing the supplements as unapproved drugs.

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