Women who eat lots of high glycemic index (GI) carbohydrates like white bread and ice cream may be at greater risk of heart disease, but men do not seem to be affected, Italian scientists said.
In a study of almost 48,000 adults, the scientists found that the 25 percent of women who ate the most carbohydrates overall had around double the risk of heart disease of the 25 percent who ate the least.
When these carbohydrates were separated into high and low glycemic index categories, the researchers found that eating more high GI foods was strongly linked to greater risk of coronary heart disease, whereas low GI foods were not.
"A high consumption of carbohydrates from high glycemic index foods, rather than the overall quantity of carbohydrates consumed, appears to influence the risk of developing coronary heart disease," the scientists wrote in a study in the Archives of Internal Medicine journal Monday.
Heart disease is the leading killer of men and women in Europe, the United States and many other rich nations. Together with diabetes, cardiovascular diseases accounted for almost one third of all deaths around the world in 2005, according to the Geneva-based World Health Organization.
High-carbohydrate diets are known to increase the levels of blood glucose and of harmful blood fats known as triglycerides while reducing levels of protective HDL or "good" cholesterol, increasing heart disease risk.
But not all carbohydrates have the same effect on blood glucose levels, and the glycemic index is a measure of how much a food raises blood glucose levels compared with the same amount of glucose or white bread.
Low GI foods include beans, lentils and nuts, whereas foods like white bread, doughnuts and ice-cream have a high GI rating.
When they analyzed the data for men — who accounted for 15,171 of the 47,749 Italian adults in the study — the researchers led by Sabina Sieri of the Fondazione IRCCS Istituto Nazionale dei Tumori in Milan found no link between overall carbohydrate intake, glycemic index or glycemic load and heart disease risk.
Among women, the 25 percent of women whose diet had the highest glycemic load had 2.24 times the risk of heart disease compared with the 25 percent with the lowest glycemic load.
This could be because the adverse changes linked to carbohydrate intake, including triglyceride levels, are stronger risk factors for heart disease in women than in men, they wrote.
The adverse effects of a high glycemic diet in women might be due to differences in the way women and men break down and absorb sugars and fats, they added.