By Adam Garcia
Today in diabetic lifestyle we will discuss studies done in 2003 on low and high glycemic index diets and how it can affect glucose levels.
A carb is not a carb is not a carb; at least when it comes to diabetes and getting control of high blood sugar. Researchers say a low glycemic index diet may be the way to go. Even foods with the same carbohydrate content can trigger a wide difference in blood sugar levels, as much as five times. It all depends 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 does glycemic index matter? Foods with a high glycemic index 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 2003 research studies, 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. Researcher Jennie Brand-Miller, PhD, and colleagues found that patients who ate a low glycemic index diet reduced their HbA1c levels by an average of 0.43 points above that produced by the high glycemic index diet. “That’s a significant enough of a reduction to get a new 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.”
Although important, the numbers can also be confusing because the glycemic index of some foods may surprise you. As a general rule, the same low-fat, high-fiber fare, fruits, vegetables, whole grains and legumes, often advised to manage weight and help prevent diabetes and other health conditions, have a low glycemic index. In opposition, starchy and processed foods such as potatoes, breads, and cereals usually have a high glycemic index, but there are exceptions. For instance, a bowl of All-Bran cereal has a glycemic index of 54, while a serving of spaghetti rates at 41, meaning the high-fiber cereal spikes blood glucose more quickly and drastically. A handful of raisins are 64, more than a serving of popcorn, at 55. White rice, which is 56, has nearly twice the glycemic index of a glass of apple juice; an orange (43) has almost half the index of watermelon (72). The American Journal of Clinical Nutrition lists any food under 55 as a low glycemic food and any food more than 70 as high glycemic.
“I remember one study that compared various foods found that a bowl of Haagen-Dazs ice cream raises blood glucose at a slower rate than a baked potato,” Bernstein comments, however, the use of diets with a low glycemic index in the treatment of diabetes remains controversial. There are contrasting recommendations around the world, the Australian researchers note in their study. One possible reason: Most of the studies thus far measuring blood sugar response to glycemic indexed foods have been encouraging but small, says Angela D. Liese, PhD, MPH. Liese recently completed her own research on how foods with high glycemic indexes affect “metabolic syndrome,” a cluster of conditions that includes obesity, high blood cholesterol, high blood pressure, insulin resistance, and diabetes. Her results have not yet been published. The Australian researchers’ analysis of 14 studies had a total of only 356 patients. Is it time for a change? Liese says, “This study is important because it shows some really encouraging data, but a lot more research is needed; if you want to get to the point of reaching new dietary recommendations, much, much larger studies are needed.”
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