Zinc, folic acid supplement does not improve male fertility

Dietary supplements containing zinc and folic acid — marketed as a treatment for male infertility — do not appear to improve pregnancy rates, sperm counts or sperm function, according to a study conducted by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), part of the National Institutes of Health.

Zinc, folic acid supplement does not improve male fertility. Photo: Brandless/Unsplash

The authors note that most so-called fertility supplements contain zinc and folic acid. Zinc is an essential mineral for sperm formation, and folate, the natural form of folic acid, depends on zinc to help form DNA in the sperm. Previous studies of these nutrients as a treatment for male infertility have produced conflicting results.

In the current trial, researchers enrolled 2,370 couples planning infertility treatments in four U.S. cities and their surrounding areas. The men were assigned at random to receive either a placebo or a daily supplement containing 5 milligrams of folic acid and 30 milligrams of zinc.

Live births did not differ significantly among the two groups: 404 (34%) in the supplement group and 416 (35%) in the placebo group. Similarly, the groups did not differ among various measures for sperm health, such as sperm movement, shape and total count.

However, the proportion of sperm DNA fragmentation—broken DNA in the sperm—was higher in the supplement group (29.7%), compared to the placebo group (27.2%). Studies have linked a high rate of sperm DNA fragmentation to infertility.

Men in the supplement group also had a higher proportion of gastrointestinal symptoms, compared to the placebo group: abdominal discomfort (6% vs. 3%), nausea (4% vs. 2%) and vomiting (3% vs. 1%).

“Our study is one of the first randomized, placebo-controlled trials to assess whether folic acid and zinc supplements help to improve male fertility,” said Enrique Schisterman, Ph.D., of the NICHD Division of Intramural Population Health Research, who conducted the trial, along with colleagues. “Our results suggest that these dietary supplements have little to no effect on fertility and may even cause mild gastrointestinal symptoms.” (National Institutes of Health)

YOU MAY ALSO LIKE

Detailed genetic study provides most comprehensive map of risk to date of breast cancer risk

A major international study of the genetics of breast cancer has identified more than 350 DNA ‘errors’ that increase an individual’s risk of developing the disease. The scientists involved say these errors may influence as many as 190 genes.

Obesity Can Affect Kids’ Working Memory

Obese children have a worse working memory than children of normal weight, a new study has found.

Changed route of immunization dramatically improves efficacy of TB vaccine

Researchers from the National Institutes of Health’s National Institute of Allergy and Infectious Diseases and their colleagues have shown that simply changing the dose and route of administration from intradermal to intravenous greatly increases the vaccine’s ability to protect rhesus macaques from infection following exposure to Mycobacterium tuberculosis, the bacterium that causes TB.

Scientists search for the clocks behind aging brain disorders

Study of flies suggests neurodegenerative disorders may speed up aging process.

Scientists Find Brain Hormone That Triggers Fat Burning

Biologists have identified a brain hormone that appears to trigger fat burning in the gut. Their findings in animal models could have implications for future pharmaceutical development.

Protein involved in hearing loss recovery

A study with mice found that a protein called FOXO3 is involved in recovery from noise-induced hearing loss.