Glycemic Index: New Way to Count Carbs?

Aug. 20, 2003 -- A carb is not a carb is not a carb -- at least when it comes to diabetes and getting control of high blood sugar. A low-glycemic index diet may be the way to go, say researchers.

Even foods with the same carbohydrate content can trigger a wide difference in blood sugar levels -- as much as fivefold. It all depends, say some researchers, on the food's glycemic index, a number that indicates how much and how quickly blood sugar increases after consuming a carbohydrate-containing food.

Why Glycemic Index Matters

Foods with a high glycemic index (and therefore a higher number) cause a sudden and drastic jump in blood sugar levels. Low-glycemic foods are more easily absorbed in the body and raise blood sugar more gradually.

In the latest research, Australian researchers analyzed data from 14 previous studies comparing the effects of high- and low-glycemic foods on blood sugar levels in people with diabetes. They then looked at results of a blood test called HbA1c_, which indicates average blood sugar levels over the past three months.

Good Enough for a New Drug

Researcher Jennie Brand-Miller, PhD, and colleagues found that patients who ate a low-glycemic index diet reduced their HbA1clevels by an average of 0.43 points above that produced by the high-glycemic index diet.

"That's significant -- enough of a reduction to get a new [diabetes] drug to market," says Gerald Bernstein, MD, former president of the American Diabetes Association and an endocrinologist at Albert Einstein College of Medicine.

"There is no question that it's important for diabetics to pay close attention to the glycemic index of foods they eat," says Bernstein, who was not involved in the study conducted by University of Sydney researchers.

"Remember, the issue in diabetes is an inability to handle glucose. Whether or not you're taking insulin, you're trying to match the body's insulin with the onslaught of glucose going in. So you really need to know the probability of how quickly blood sugar is going to bounce so you can better manage your disease. When you eat a baked potato, glucose levels spike in milliseconds. With legumes or fruits and vegetables, they go up in about 30 minutes."