Can zinc and folic acid supplements for men improve sperm quality and births in couples experiencing infertility?

This study examined if zinc and folic acid supplements for men improved sperm quality and the number of births in couples planning infertility treatment. The authors found that zinc and folic acid did not improve sperm quality or birth rates compared to a placebo.

In men, infertility can arise due to a number of factors including sperm quality. Sperm quality is affected by the volume of semen and the numbers, movement, and shape of sperm cells. Several dietary supplements claim to improve sperm quality and treat infertility.

Zinc helps to stimulate the creation of sperm cells. Folic acid is needed to make new DNA, also required to make sperm cells. Trials that examined the use of zinc and folic acid to treat infertility in men have shown mixed results. A large trial examining the effectiveness of zinc and folic acid supplements for improving sperm quality and treating infertility is needed.

2370 men from couples experiencing infertility were divided into two groups. The first group (1185 men) received daily zinc (30 mg) and folic acid (5 mg) supplements for 6 months. The second group (1185 men) received a placebo for 6 months. The main outcomes were sperm quality and live birth rate.

Zinc and folic acid supplements did not improve the number of couples who had a baby. 34% of couples in the supplement group and 35% of couples in the placebo group had a live birth.

Zinc and folic acid supplements also did not improve sperm quality. The average sperm concentration was 84.8 million sperm/mL of semen in the supplement group and 89 million/mL in the placebo group. Sperm motility (movement) was 52.7% in the supplement group and 53.2% in the placebo group. Normal sperm shape was found in 5.7% of men in the supplement group and in 6% in the placebo group. The volume of semen was 3.5 mL in both groups. 

DNA quality in sperm cells was reduced by zinc and folic acid supplements. Average DNA damage was 29.7% in the supplementation group and 27.2% in the placebo group.

Serious side effects were experienced by 7 patients in the supplement group and 5 patients in the placebo group. However, none of these were linked to treatment.

The authors concluded that zinc and folic acid supplements for men did not improve sperm quality and live birth rates in couples seeking treatment for infertility.

This study used a short follow-up to examine the number of births. The patients in this study were mostly of the same race and so results may not reflect the whole population. Also, some patients were lost at follow-up, therefore the results may have been affected.