Women who consume large amounts of certain high-carbohydrate foods increase their risk of heart disease, a study said Monday.
The study showed an increased incidence of coronary disease in women -- but not men -- whose diet is rich in foods with a "high glycemic index," such as white bread, sweets and some sugary breakfast cereals.
The study noted that all high-carbohydrate diets increase the levels of blood glucose and harmful blood fats known as triglycerides while reducing levels of protective HDL or "good" cholesterol, thereby increasing heart disease risk.
But the researchers found not all carbohydrates have the same effect on blood glucose levels.
They concluded that blood glucose and triglycerides were impacted more by foods with a high glycemic index, compared with other carbohydrates with a lower index, such as fruits, vegetables and whole grains.
Lead researcher Sabina Sieri of Italy's Fondazione IRCCS Istituto Nazionale dei Tumori and her colleagues studied 47,749 Italian adults, including 15,171 men and 32,578 women who completed dietary questionnaires.
Those women who consumed the most carbohydrates overall had roughly twice the risk of heart disease as those who consumed the least.
When these carbohydrates were separated into high- and low-glycemic index categories, the difference was more pronounced.
Women whose diet had the highest glycemic load had 2.24 times the risk of heart disease compared to those with the lowest glycemic load.
"Thus, 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 authors said.
The study also concluded that overall carbohydrate intake, glycemic index and glycemic load were not associated with heart disease risk in men. This could owe to higher triglyceride levels being stronger risk factors for heart disease in women than in men.
"We tentatively suggest that the adverse effects of a high glycemic diet in women are mediated by sex-related differences in lipoprotein and glucose metabolism," the researchers said, cautioning that further prospective studies were needed to verify that there was indeed no association between a high dietary glycemic load and cardiovascular disease in men.
The study was published in Archives of Internal Medicine, an American Medical Association publication.