Low-fat fertility risk

A fertility specialist from the US has warned that women who live on low-fat diets could be at a higher risk of infertility. Professor Rose Frisch, who wrote the book 'Female fertility and the body fat connection' says that even women who are slightly underweight may have problems conceiving.

Professor Frisch, from a division of Harvard University, says that a woman's sexual development and the functioning of her reproductive system are closely linked to the amount of body fat she carries. A certain amount of fat is crucial to enable everything to function properly, she says. She has devised a 'critical-fatness theory', which she has compared to the official scientific body mass index (BMI) chart. She says this shows at which weight women of different heights and weights may become infertile. She predicts that if the BMI is below 18-19, ovulation will cease, although menstruation may continue. If levels fall even lower, menstruation may stop altogether.

It has long been recognised that being excessively under- or overweight can affect a woman's fertility, but Professor Frisch believes that losing as little as three pounds can make the difference. Body fat in women controls the flow of leptin, a hormone which controls appetite and energy and also affects reproduction. If the body does not have the right amount of fat, the brain gradually switches off the supply of leptin, which lessens the ability to conceive.