THURSDAY, June 1 (HealthSCOUT) -- If you think a high-carb, low-fat diet is always a healthy diet, think again.
The popular antidote to heart disease actually could raise your risk for the disease, says a new Harvard Medical School study.
Dietary guidelines often overlook a critical distinction in the types of carbohydrates, failing to go beyond their traditional classification as simple sugars or complex starches, says the study, which appears in the current American Journal of Clinical Nutrition.
Carbohydrates such as bleached rice and processed potatoes, for instance, break down quickly and result in a blood sugar and insulin spike two or three hours after eating. These refined carbohydrates also can reduce HDL, or good cholesterol, and increase the risk of heart disease, especially among overweight women, the study says.
Other carbohydrates, like beans and other legumes, break down much more slowly and produce a more gradual rise in glucose and insulin, which the researchers say is healthier and more likely to prevent heart disease.
"We certainly hope this is a wake-up call and that dietary guidelines will be changed accordingly," says lead researcher Dr. Simin Lui, director of nutrition research and an instructor at Harvard Medical School.
"The low-fat, high-carbohydrate diet that is recommended really is not optimal for prevention of chronic heart disease. It can actually increase the risk of chronic heart disease," Lui says.
His study followed more than 75,500 female nurses, all over age 38 and without a previous diagnosis of diabetes or cardiovascular disease. At the end of 10 years, 761 had developed chronic heart disease, and 208 died of it.
To focus on the link between eating habits and heart disease, researchers say they adjusted for other coronary risk factors, such as smoking and age.
Americans, bent on reducing fat in their diets, have increased consumption of grains, fruits, vegetables and other carbohydrates, generally lowering their LDL, or bad cholesterol.
But a diet high in carbohydrates also may reduce HDL, the good cholesterol, raising triglycerides, the chemical form of fat in the body, says the American Heart Association (AHA). Clogged arteries can result and can contribute to a heart attack or stroke.
The AHA recommends that 55 percent of calories come from carbohydrates, mostly complex carbohydrates, including vegetables, fruits and grains. Complex carbohydrates add more fiber, vitamins and minerals to the diet than simple carbohydrates, which are high in refined sugars.
Wahida Karmally, a research dietician and director of nutrition at the Irving Center for Clinical Research at Columbia University, says the new findings underscore the importance of distinguishing between carbohydrates.
"People have to understand that carbohydrates are not a 'free' food, in the sense that you can eat as much as you want. All carbohydrates are not created equal. The simple carbohydrates do not provide the vital nutrients the complex provide," Karmally says.
Karmally also suggests paying more attention to overall calorie intake, keeping physically active and eating lots of vegetables and fruits that also act as anti-oxidants.
What To Do
A balanced diet is always best. Avoid extremes or the latest fad. Talk to your doctor about how to meet your nutritional needs.
For more information, check the dietary recommendations from the AHA. And compare your eating habits with the U.S. Department of Agriculture's Food Guide Pyramid.