Folate: not just for pregnant women Original paper

Proper intake of the B vitamin folate (folic acid) during pregnancy has been long established to reduce the risk of infant physical defects like spina bifida, which is an improper formation of the spinal cord. Maintaining a healthy folate status may also improve male fertility and sperm health.

This was a systematic review and meta-analysis of experimental and observational studies in animals and humans. In total, 23 articles were analyzed: 6 animal studies, 1 human and animal combined study, and 16 human studies. Researchers were able to meta-analyze four randomized controlled trials of 164 males supplementing 5 mg of folic acid per day.

Based on the meta-analysis, a 5 mg daily dose of folic acid may improve sperm concentration and motility. This effect may be more pronounced in subfertile males or males with low folic acid concentrations. No meaningful effect was observed for sperm normal morphology (i.e., normal sperm shape).

Animal data has shown positive but small associations between healthy male folate status and improved pregnancy outcomes, like fetal development and decreased odds of physical malformations.