Evidence from randomized controlled trials was found to support a link between antioxidant supplementation and improvements in male fertility linked to sperm quality, according to a review published in Reproductive BioMedicine Online.
Reviewers led by Tarek El-Toukhy from London’s Guy’s and St. Thomas’ Hospital NHS Foundation Trust note however, that the evidence is not consistent and more studies are therefore required before antioxidant supplements can be recommended to infertile men.
“It is imperative these studies employ strict inclusion and exclusion criteria and standardized methodology to help understand whether a specific group of infertile men is more likely to benefit from antioxidant therapy,” they stated.
The link between antioxidants and fertility measures is not new. Oxidative stress, caused by a disruption to the balance of antioxidants and pro-oxidants, has been reported to reduce the quality of sperm. According to Dr El-Toukhy and his co-workers, about 15 percent of couples of reproductive age are affected by infertility issues, with 50 percent of these cases related to impaired semen.
Scanning the science
In order to elucidate if antioxidants supplements may benefit infertility measures, the researchers conducted a systematic review of the literature. They found 17 randomized clinical trials involving vitamins C and E, zinc, selenium, folate, carnitine and carotenoids in relation to sperm quality and pregnancy rates.
Data was available for 1,665 men from 17 trials. Results showed that antioxidant supplementation was associated 75 percent of the trials showed an “improvement in at least one sperm parameter compared with placebo or no treatment”. Moreover, 63 percent of the studies showed significant improvements in sperm motility compared with placebo, while only 33 percent of trials showed an improvement in sperm concentration.
Regarding pregnancy rates, the London-based reviewers report that antioxidant supplementation was associated with a higher pregnancy rate of 19 percent, compared with only 3 percent in placebo/ control groups.
“This review shows that oral antioxidant therapy was associated with a significant improvement in spontaneous and assisted conception pregnancy rates in six of the 10 randomized studies identified in the database search,” wrote the researchers.
“This finding could possibly be explained, at least in part, by the antioxidant-related improvement in either sperm motility and total motile sperm count, both of which have been reported to predict male fertility or sperm DNA integrity,” they added.
Source: Reproductive BioMedicine Online
Volume 20, Pages 711-723
“A systematic review of the effect of oral antioxidants on male infertility”
Authors: C Ross, A Morriss, M Khairy, Y Khalaf, P Braude, A Coomarasamy, T El-Toukhy