Supplement business “unlikely to be affected” by findings that zinc and folic acid do not boost male fertility

09 Jan 2020 --- Men should no longer be advised to take zinc and folic acid supplements as a way to boost their fertility, according to a new study. A team of researchers at Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), part of the National Institutes of Health, found that the ingredients – often marketed toward men struggling with infertility – do not appear to improve pregnancy rates, sperm counts or sperm function. However, one fertility supplement company is unconcerned by these findings, noting the number of conflicting studies.

“We hypothesized based on prior smaller studies that the zinc and folic acid combined supplement would improve semen quality, so we were surprised to find no apparent improvement. Also, since folic acid and zinc were thought to support DNA transcription and reduce oxidative stress, we were also surprised to find a small degree of harm from supplementation on the DNA fragmentation index, which is a measure of sperm DNA quality,” Dr. Enrique Schisterman of the NICHD Division of Intramural Population Health Research tells NutritionInsight.

Published in the Journal of the American Medical Association, the study enrolled 2,370 couples planning infertility treatments in four US reproductive endocrinology and infertility care study centers between June 2013 and December 2017. The men were assigned at random to receive either a placebo or a daily supplement containing 5 mg of folic acid and 30 mg of zinc.  

The researchers found that the supplementation did not help treat infertility. Live birth did not differ significantly between treatment groups, with 404 births in the supplementation group and 416 the placebo group. Moreover, neither were most of the semen quality parameters – sperm concentration, motility, morphology, volume and total motile sperm count – significantly different between treatment groups at six months after randomization.

Notably, the researchers observed a statistically significant increase in DNA fragmentation with folic acid and zinc supplementation. The supplementing men also experienced gastrointestinal (GI) symptoms more commonly, suffering from abdominal discomfort (6 percent versus 3 percent), nausea (4 percent versus 2 percent) and vomiting (3 percent versus 1 percent).

Recommendations for the future
The researchers found that the zinc and folic acid supplementation did not help treat male infertility.These results suggesting the inefficacy of zinc and folic acid supplements in tandem with the GI symptoms have led the researchers not to recommend supplementation. “Though dietary supplements are commonly assumed to ‘do no harm,’ our findings indicate that healthcare providers should not recommend using such supplementation for male fertility. They should also consider cautioning patients against using supplements until more is known about potential risks,” says Dr. Schisterman.

He further explains that previous small studies indicated how the combination of folic acid and zinc supplementation improved some parameters of semen quality. These potential positive effects were generally attributed to folic acid and zinc involvement in supporting DNA synthesis as part of sperm replication and reduction of oxidative stress. “However, our study is one of the first randomized, placebo-controlled trials,” says Dr. Schisterman. The team will continue to investigate the data, hoping to uncover the reasons behind the observed results. 

Nonetheless, the market proliferates with a large number of supplements for men’s fertility containing zinc and folic acid. One example is Proceive for Men, which includes over 26 ingredients including zinc and folic acid, as well as selenium, vitamin B12 and vitamin D. A Proceive spokesperson tells NutritionInsight that this latest study is unlikely to affect the company.

They highlight that the European Food Safety Authority (EFSA) has approved a variety of health claims relating to fertility, including that zinc contributes to normal fertility and reproduction and it has a role in the process of cell division. Meanwhile, folate contributes to the normal function of the immune system and also has a role in the process of cell division.

“While this new scientific study claims that supplements containing zinc or folic acid do not boost male fertility, there are many studies that prove that both have a role in the reproductive process and male fertility,” they add.  

Folic acid is also a buzzword in the pregnancy sector, touted as essential for ensuring fetuses’ healthy development. Pregnant mothers may not be supplementing enough, a study found last November, indicating that active folate supplementation may be more beneficial to fetuses’ development than folic acid itself. 

Finally, the International Alliance of Dietary/Food Supplement Associations (IADSA) also underlines the importance of folic acid in the first 1,000 days of a baby’s life. 

By Katherine Durrell and Anni Schleicher