WOMEN who want to have babies are not the only ones who need extra folic acid—would-be fathers may also benefit.
Women planning to get pregnant are advised to take at least 40 micrograms of folic acid daily. This greatly reduces the chances of birth defects in which the spine does not form properly, such as spina bifida. Now Regine Steegers-Theunissen of the University of Nijmegen in the Netherlands and her colleagues have found that the vitamin, combined with zinc, can nearly double the numbers of healthy sperm produced by men with fertility problems.
“It’s one of the first papers to show that optimising nutrition can improve sperm quality,” says Lynn Wallock of the Children’s Hospital Oakland Research Institute in California. “It shocks me to realise how little work has been done on diet and sperm.”
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About 15 per cent of couples have trouble conceiving, says Steegers-Theunissen, and the problem is as likely to be with the man as the woman. To see if folic acid made any difference, her team compared 107 fertile men whose partners were pregnant with 103 “subfertile” men who had tried for a year to conceive without success.
The volunteers provided semen samples and blood samples. All had similar levels of folic acid and zinc in their blood, and none had any deficiencies. But the subfertile volunteers had only between 5 and 20 million sperm cells per millilitre of semen, whereas most fertile men have over 20 million.
All the men were then randomly assigned to one of four groups. Each group took a different combination of supplements for 26 weeks: zinc sulphate and a placebo; folic acid and a placebo; zinc plus folic acid; or two placebo tablets. At the end of this period, fresh blood and semen samples were taken.
For most of the men there were no significant changes. But in the subfertile men who took both zinc and folic acid, there was a 74 per cent increase in the number of healthy sperm they produced.
The researchers aren’t sure exactly how this combination improves sperm concentrations. But Steegers-Theunissen thinks it has to do with the nutrients’ essential role in the synthesis of DNA and a molecule involved in protein synthesis called transfer RNA.
Even with these increases, most of the men were still subfertile. “But the more you have, the greater your chances … you only need one,” says Steegers-Theunissen.
It’s an important advance, says Bruce Ames of the University of California, Berkeley. Last year his group showed that folic acid deficiency is associated with low sperm count and quality. They also found that a lack of vitamin C, especially in smokers, damaged sperm. “I think everybody should take a multivitamin and mineral pill as insurance,” Ames says.
And taking folic acid has other benefits. The vitamin also cancels out the genetic risk of colon cancer and reduces blood levels of homocysteine, a compound that contributes to heart attacks and strokes. Another recent study in mice suggests folic acid can reduce the risk of Alzheimer’s.
- More at: Fertility and Sterility (vol 77, p 491)