Antioxidants do not improve sperm quality

Researchers have found that despite studies that claim that antioxidants are good for sperm production, a new study has shown that there is no such benefit.

Image Credit: Kateryna Kon / Shutterstock
Image Credit: Kateryna Kon / Shutterstock

Professor Anne Steiner from the University of North Carolina at Chapel Hill, USA, led this this study titled, “Antioxidants in the treatment of male factor infertility: Results from the double blind, multi-center, randomized controlled Males, Antioxidants, and Infertility (MOXI) trial.” She would be presenting the results this week at the 34th Annual Meeting of ESHRE in Barcelona. The new study was conducted in eight American fertility centres and was supported by the National Institutes of Health.

This was a large clinical trial including 174 couples. The researchers found that if the male partner was given an antioxidant supplementation for a minimum of three months, there was no significant improvement in the sperm concentration, motility or morphology. The rates of DNA fragmentation was also unaltered. This meant that antioxidants did not benefit the sperm quality.

The participating males in the study had all been diagnosed with a male factor infertility and had a below normal sperm concentration, motility and morphology and also had higher rates of DNA fragmentation. Normal sperm concentration for male fertility is greater than 15 million per millilitre with a motility of 32 percent or higher and a normal morphology of 4 percent or more. The males in this study had a concentration of less than 15 million/ml, motility of less than 40 percent and normal morphology of less than 4 percent. They had a DNA fragmentation rate of 25 percent or more to be eligible for the study.

At the start of the trial and at the end of the three month period of medication, the sperm parameters were measured. During the three month period half of the men were given a tablet containing vitamins C, D3 and E, folic acid, zinc, selenium and L-carnitine. These are known to contain antioxidants. The other group was given placebo tablets.

Results at the end of three month study period showed that there was a “slight” difference overall in the sperm concentration between the two groups of men. There were no significant differences in sperm motility, morphology and DNA fragmentation. Results revealed that at the end of the three months of the trial the rates of DNA fragmentation were 28.9 percent in the antioxidant treated men and 28.8 percent in the placebo group. These rates were both high and similar proving no additional benefits with antioxidants.

The researchers also looked at the chances of a natural conception at the end of the study and found that pregnancy rates were 10.5 percent in the antioxidant group and 9.1 percent in the placebo group. The participating males were asked to continue their antioxidants or placebo tablets for three more months. The female counterparts were given three cycles of clomifene (ovarian stimulating drug to induce fertility) and intrauterine insemination. The rates of pregnancy at the end of six months remained the same in both groups.

Steiner explained that this was one of the largest randomized clinical trials to test the effects of antioxidants on male fertility. She said that antioxidants are known to benefit even after a short duration of administration because of the ability to counteract the negative effects of the reactive oxygen species. This explained why they chose a three month study period.

The study concludes that the “results do not support the empiric use of antioxidant therapy for male factor infertility in couples trying to conceive naturally.”

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


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