News

23rd June 2005

Avoiding soya may help fertility

Women should avoid eating soya products around their fertile time of the month if they are trying for a baby, according to a fertility expert.

Professor Lynn Fraser, from King's College London, has told a European fertility conference that a compound in soya called genistein sabotages the sperm as it swims towards the egg.

She added that avoiding soya at certain times in a cycle may help women to conceive.

Professor Fraser tested what happened to human sperm exposed to genistein in a dish in the lab.

The compound kick-started a reaction in a large proportion of the sperm that gives them the ability to fertilise an egg, a reaction that doesn't normally happen until the sperm are close to completing the long swim to the egg.

Professor Fraser therefore believes that if women have genistein in and around the womb this could hamper conception by making sperm peak too soon.

This could mean they would not be able to fertilise the egg, she told the annual meeting of the European Society for Human Reproduction and Embryology.

Further tests showed that more genistein was needed in mice than humans to affect the sperm.

"We were really surprised. Human sperm proved to be even more responsive than mouse sperm to genistein, responding to very low concentrations - well within the amounts that have been measured in people's blood."

She said it was not yet known how much soya might be a safe amount to avoid this effect.

"It's not a question of completely stopping eating products containing soya.

"But it might be best for a woman to avoid them for a few days around the time she is ovulating."

Dr Allan Pacey, Senior Lecturer in Andrology at Sheffield University and Secretary of the British Fertility Society said, "It's early days but clearly if what happens in the laboratory also occurs in the woman's fallopian tube as the sperm make their way to the egg, then there would be the potential for fertilisation to fail."

A spokeswoman from the Vegetarian Society said, "For anyone struggling to become pregnant, avoiding soya products for a few days a month is worth a try if there is even a slim chance that it will help increase fertility.

"Obviously many vegetarians and vegans use soya in their diet, however as there are lots of vegetarian and vegan alternatives to dairy, milk and meat on the market, it shouldn't pose a problem."

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