Carbohydrates and heart disease

Researchers in Italy followed more than 47,000 people for an average of almost eight years. Diet questionnaires completed at the beginning of the study assessed the amount of carbohydrates and high-glycaemic-index and low-glycaemic-index foods in the participants’ diets, and their overall dietary glycaemic load (another measure of the effects of diet on blood sugar levels). The researchers noted the following:

• Women with the highest carbohydrate intake were twice as likely to develop heart disease during the study as women with the lowest intake.
• Only high-glycaemic-index carbohydrates were associated with heart disease risk; low-glycaemic-index carbohydrates were not.
• Having a high dietary glycaemic load more than doubled the risk of heart disease in women.
• No relationship between heart disease and carbohydrate intake, high-glycaemic index food consumption, or dietary glycaemic load was seen in men.

Not all carbs are created equal

While these findings show that a high-carbohydrate diet can put women at risk for heart disease, it is important to note that complex, low-glycaemic-index carbohydrates are not the culprits.

“Our finding that only carbohydrates from high-glycaemic-index foods increased cardiac risk suggests that the quality of the carbohydrates is more important than the amount when it comes to preventing heart disease,” said study co-author Dr. Vittorio Krogh of the Fondazione IRCCS Istituto Nazionale dei Tumouri in Milan, Italy.

Reducing your glycaemic load

Keeping in mind that high-calorie, high-carbohydrate foods with high-glycaemic-index values raise the dietary glycaemic load and increase women’s heart disease risk, here are some tips to help women choose heart-healthy carbohydrates:

• Whole is best. Processed carbohydrates are easier for the body to convert to blood glucose, and therefore have higher glycaemic index values than their whole-food sources.
• Fruits and vegetables generally have a low glycaemic load, but the load goes up when they are dried or juiced.
• Glycaemic loads for whole grains and whole grain products are generally lower than those for white flour products, white rice, and grains processed in order to be prepared “instantly.”
• Beans, lentils, nuts, and seeds are good for the heart and good for keeping your glycaemic load down.

(Arch Intern Med 2010;170:640–7)