Folic acid improves a man's chance of becoming a father

According to new research from the U.S. men who want to father a child will improve their chances by taking folic acid supplements.

The research has revealed a link between high levels of the nutrient in men's diets and the genetic quality of sperm.

The researchers say men with the highest levels of folic acid had the lowest proportion of sperm harbouring genetic changes that can lead to Down's syndrome and miscarriages.

While the scientific case for women who are trying to conceive and folic acid is well established, the idea that diet can improve sperm quality is less well established.

The synthetic form of folate (a B vitamin) is essential for development and a deficiency during the early stages of pregnancy can lead to neural tube defects in the baby, including spina bifida.

Fertility experts say there is increasing evidence which suggests that dietary factors can affect sperm health but the best advice to men is to stop smoking, drink in moderation and eat a balanced diet.

For the study Professor Brenda Eskenazi an expert in Maternal and Child Health and Epidemiology at the University of California, Berkeley, specifically examined how micronutrients affect sperm quality.

They took sperm samples from 89 healthy, non-smoking men and asked detailed questions about diet and supplement intake and say there was an association between levels of folate in the diet and the numbers of sperm displaying aneuploidy - chromosomal abnormalities that can lead to failure to conceive and Down's syndrome.

The researchers say they found no consistent association between dietary zinc, vitamin C, vitamin E and beta-carotene and sperm quality.

Professor Eskenazi suggests men trying to father a child should consider taking multivitamin supplements containing folate.

The current recommended daily intake (RDA) for men aged over 19 is 400 micrograms, and the researchers say if other studies confirm their findings then a possible intervention would be to increase the RDA for men considering becoming fathers for at least three months before trying to conceive, in order to reduce the risk of chromosomal abnormalities in their children.

The study is published in the reproductive medicine journal, Human Reproduction.