News about the Mediterranean diet just keeps getting better.

It has already been touted as the diet that lets you live longer, lower your risk of heart disease and cancer, and lower your cholesterol.

Here is another point in its favour. An observational study said that women who eat a Mediterranean-style diet, rich in vegetables, vegetable oils and fish may have a higher likelihood of becoming pregnant after infertility treatment.

Researchers in the Netherlands found that among 161 couples undergoing fertility treatment at their centre, women whose eating habits most closely matched the traditional Mediterranean diet were 40 per cent more likely to become pregnant than those with the least Mediterranean-like diets.

In the study, which was reported in the journal Fertility And Sterility, couples were separated into groups based on their usual diet patterns. Later, fertility treatment results were noted.

While the study does not prove that the diet boosts its success, the findings point to a possible role for diet in fertility treatment, said the researchers.

In an e-mail message to Reuters Health, lead researcher Regine Steegers-Theunissen of Erasmus University Medical Center in Rotterdam suggested that couples considering fertility treatment eat a balanced diet that includes healthy doses of vegetable oil, vegetables, beans and fish.

Before treatment, the couples completed detailed questionnaires on their eating habits over the past month.

When the researchers analysed the data, they identified two common diet patterns among the women. The Mediterranean diet - defined as high in vegetables, vegetable oils, fish and beans, but low in snack foods - and the second, the health-conscious diet - which is high in fruits, vegetables, whole grains, beans and fish, and low in meat and snack foods.

The researchers found there was no link between the health-conscious diet and rates of pregnancy. However, the group that most closely adhered to the Mediterranean diet was more likely to become pregnant.

The researchers did not assess pregnancy outcome, so the diet's relationship to the ultimate success of fertility treatment is not clear.

The Mediterranean and health-conscious diets had many similarities, but there are a few potential reasons why the former may affect fertility treatment success, said the researchers.

One is the high intake of vegetable oils in the Mediterranean diet. The researchers noted that the omega-6 fatty acids in these oils are precursors to hormone-like substances in the body called prostaglandins.

Prostaglandins, in turn, are involved in the menstrual cycle, ovulation and pregnancy maintenance.

In addition, the study found that women who most closely followed the Mediterranean diet had higher levels of vitamin B6.

One previous study found that giving vitamin B to women who were having difficulty getting pregnant increased their chances of conception.

Still, diet is part of a person's overall lifestyle and the study could not account for all of the factors that could explain the connection between the Mediterranean diet and pregnancy rates.

This article was first published in Mind Your Body, The Straits Times.