Eating the Wrong Kind of Carbohydrates Increases Heart Disease Risk

A new study suggests it's the kind of carbs we eat, not the amount, that increases heart disease risk.

Video: The Dangers of Heart Disease

Our love affair with carbohydrates is hard to break: Time and again, we try to swear off pretzels, bread, and pasta­­—usually in an effort to lose weight­—only to embrace them again after feeling deprived. Turns out, though, we might not need to cut back on all carbs, only certain ones.

That's according to a new study published in today's Archives of Internal Medicine, which found that women who ate the most "high-glycemic" carbohydrates—which cause quick spikes in blood sugar levels—had more than twice the risk of having heart disease as those who ate the least. (The study didn't find the same association in men.) What's interesting, though, is that it was the type of carbs, not the amount, that had the health impact. "High consumption of carbohydrate from high-glycemic foods, rather than overall quantity of carbohydrate consumed, appears to influence the risk of developing heart disease in women," says study leader Sabina Sieri.

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"Bad" carbs score high on the "glycemic index," which assigns each food with a numerical value based on how quickly it raises a person's blood sugar levels. (To develop this index, researchers spent years assessing the potential of various carbohydrates to raise blood sugar.) High-glycemic carbs include white starches and candy, but also surprising foods like baked potatoes, watermelon, and brown rice. "Good" carbs, which include most fruits and vegetables, grainy breads, and pasta, cause a more gradual rise in blood sugar leading to a slower release in the hormone insulin, which moves glucose out of the bloodstream and into cells where it's used as fuel or stored as fat. Slowing this digestive process appears to limit wreckage to cells triggered by elevated blood sugar, possibly protecting against heart disease, diabetes, and other ills. The new study adds to previous research showing that following a low-glycemic diet enabled those with type 2 diabetes to have better control over their blood sugar and rely less on medications than those who ate high-glycemic carbohydrates like white bread and potatoes. Other research suggests that switching to low-glycemic carbs aids in weight loss efforts and might even stave off acne and age-related blindness.

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"It's a good idea for people to choose foods with a lower glycemic index over higher ones," recommends Sieri. A sensible rule of thumb is to choose mainly carbs that have a glycemic-index value of 55 or less; those 56 to 69 are considered moderate, and those 70 and above are considered high. Here's a listing of popular foods, but remember that serving sizes still count. Eating super-sized portions of any carbohydrate can cause blood sugar levels to soar, and excess calories usually spells trouble for your waistline. The key is to substitute good carbs for the bad ones without eating more of them. Here are some ideas:

1. Switch to darker breads. The best choices are coarse breads sprinkled with seeds and whole grains like cracked or sprouted whole-wheat breads; rye, sourdough or whole-wheat pita bread. (Stick with a slice, not half a loaf.) Worst choices? Bagels, croissants, French bread, kaiser rolls, and, of course, white bread.

2. Choose high-bran or whole-grain cereals. This can be a little confusing, since some of the nutritious cereals, like Shredded Wheat, Cheerios, and Cream of Wheat have a higher-glycemic index than the more-processed Honey Smacks or Special K. The best cereal choices include compact, noodle-like, high-bran cereals like All-Bran and Fiber One and coarse whole-grain cereal like Kashi; other good breakfast choices include slow-cooked, steel-cut oatmeal, and cereal mixed with psyllium, a soluble fiber that slows digestion of carbs.

3. Elect pasta over rice. While pasta is packed with carbohydrates, a 2-ounce serving cooked al dente raises blood sugar levels less than a baked potato or a serving of brown rice. Other good side dishes include boiled barley, bulgur, kasha, beans, and sweet potatoes.