Specialists believe such a diet could help the majority of women wanting to get pregnant naturally as well.

By contrast eating lots of saturated fat, found in dairy products and red meat, appears to damage women's fertility. High saturated fat intake has already been linked to lower sperm counts.

Dr. Jorge Chavarro and colleagues at the Harvard School of Public Health in the U.S., looked at how intake of different types of fats affected success of IVF treatment in 147 women, mostly in their 30s.

They found the women who ate the most monounsaturated fat had up to three times the chance of giving birth via IVF as those who ate the least.

Specifically the top third, who derived on average 25% of their calories from monounsaturated fat, has three times the chance of success compared to the bottom third, who derived on average 9% of their calories from it.

However, those who ate the most saturated fat produced two fewer eggs suitable for test-tube fertilisation than those who ate the least: nine compared to 11.

Chavarro said, “As far as the best fat profile is concerned, this is the fat profile that you would find in a Mediterranean diet.”

However, he cautioned that the study was very small and the findings needed to be replicated in larger numbers before firm advice could be issued.

Nonetheless, he continued,“Even though we don't know for sure if it will be of benefit, we do know it won't be harmful.”

This was because numerous studies had shown Mediterranean-style diets to have a protective effect on health, particularly regarding heart disease.

The Harvard study also looked at the role of polyunsaturated fats, commonly thought to be healthy.

They found that -- perhaps unexpectedly -- women with higher intakes of polyunsaturated fats tended to have lower quality eggs.

However, Jorge, a nutritionist and epidemiologist, explained there were different types of polyunsaturated fats -- some that could hinder fertility and others that could help.

He said the women in the study tended to eat lots of omega-six polyunsaturates, found in corn and canola oils.

He believed omega-three polyunsaturates, found in oily fish like salmon, were not harmful to fertility.

Women hoping to conceive should not stop eating them, he said.

The study, presented this week at the annual meeting of the European Society for Human Reproduction and Embryology (ESHRE) in Istanbul, was not big enough to tease out the differences between the two types, he added.

Exactly why different types of fat have different effects on fertility is currently unclear, although Chavarro said they were “known to have different effects on biological processes which may influence the outcome of assisted reproduction.”

Richard Kennedy, general secretary of the International Federation of Fertility Societies (IFFS), commented: “We know that many lifestyle activities can make it harder to conceive.

“This work reinforces the need for a good lifestyle for those trying to have a baby; eat and drink in moderation, and don't smoke.”

 From the July 5, 2012, Prepared Foods Daily News