Men with the most unsaturated fat in their diets were 18 per cent less likely to develop gallstones compared with men who ate the least, report researchers in the Annals of Internal Medicine (volume 141, issue 7, pp 514-522).
Their 14-year study also showed that the protective effective was strongest for men who were heavier and less physically active.
Gallstone disease is a major source of morbidity in developed countries and an important risk factor for gallbladder cancer. About 10-15 per cent of the US population (20 million people) have gallstones, and 1 million new cases are diagnosed yearly, according to the US National Institutes of Health.
Other research has suggested that diets high in saturated fat and refined carbohydrates increase the risk of gallstones while recent studies have linked eating nuts - rich in healthy fats - with a reduced risk of gallstones.
The study analysed information on eating habits from more than 2,300 men that reported new cases of gallstone disease between 1986 and 2000. Those in the highest quintile of unsaturated fat consumption had an 18 per cent lower risk of gallstones than those in the lowest quintile, who eat about half as much unsaturated fat as the highest group.