Women only need to eat an extra 100 grams of saturated fat a week to increase their chances of dying from heart disease by nearly 40%, a study published yesterday shows.

The research was based on 2,700 British men and women between the ages of 40 and 75, who took part in a 1984 study, the Health and Lifestyle Survey.

David Boniface, head of statistics at the University of Hertfordshire, who monitored this group of people until 2000, found there was a direct link between the amount of saturated fat women ate and coronary heart disease rates.

The participants' diets were assessed through questions about how often they ate items from 30 different food groups and the amount of bread, butter, margarine, milk, coffee, tea and sugar they consumed.

Mr Boniface excluded people with illnesses or a condition which influenced their diet, or which carried an increased risk of heart disease.

The research found that for men there was no relationship between dietary fats and coronary heart disease. But it did find for women, a "substantial and statistically significant relationship" between these two factors. It stated: "Analysis separately for age groups 40-59 and 60-75 showed that the relationship appeared to be stronger for the older women."

It found women aged about 55 years who ate an extra 100 grams of saturated fat each week had a 38% increased risk over the following 16 years of dying from heart disease.

Mr Boniface said: "The link between eating saturated fat and the likelihood of dying from coronary heart disease is clear cut for women."

He suggested the possible reasons behind the different outcome for females and males might partly rest with the fact that 29% of the women surveyed bought and prepared food they ate and so, compared with men - who were more frequently eating at work - could have given more accurate reports of their diets.

Additionally, smoking and alcohol might relate to dietary fat and heart disease in different ways for men and women. Social class could also play a role because of access to health related resources.

The average consumption of saturated fat for a woman was about 240 grams a week. The researchers looked at women whose intake varied by plus or minus 50 grams. They found women who ate 290 grams weekly had a 40% increased risk of dying from coronary heart disease compared to those who consumed 190 grams.