Diabetics are no longer limited to a high-carbohydrate
/low-fat diet, according to the latest guidelines issued by the American Diabetes Association (ADA). While that eating plan still is considered healthy, diabetics now may choose a high-monounsaturated diet instead.

Dr. Abhimanyu Garg, professor of internal medicine and chief of nutrition and metabolic diseases at UT Southwestern, served on the panel of 12 experts convened by the ADA that formulated the new evidence-based guidelines, which emphasize individualized diets and a variety of food choices. Dr. Garg's research showing the benefits of a high-monounsaturated fat diet was instrumental in leading to the change in guidelines.

In a landmark multicenter study in 1994, Dr. Garg found that a diet rich in monounsaturated fats improved the heart health of patients with non-insulin dependent (type 2) diabetes, when compared to a diet high in carbohydrates. Dr. Garg's research led to a major revision in the ADA's dietary guidelines that same year. "In the past, a diet rich in carbohydrates and low in fats was recommended to all patients with diabetes," Garg said. "We found that a diet rich in monounsaturated fatty acids led to improvement in HDL (high-density lipoprotein) cholesterol, triglycerides and, most importantly, diabetes control.
"Now diabetics can choose a diet rich in carbohydrates or a diet rich in monounsaturated fats. We can now offer them a choice, which they are more likely to stick to and are more compliant with."

Specifically, the new guidelines recommend that carbohydrate and monounsaturated-fat intake should account for 60 percent to 70 percent of caloric intake, and 15 percent to 20 percent of caloric intake should come from protein. Carbohydrate food sources recommended by the panel include whole grains, fruits, vegetables and low-fat milk. Olive, canola and peanut oils, as well as avocados and some nuts, are rich in monounsaturated fats. According to the new guidelines, less than 10 percent of caloric intake should come from saturated fats.

The guidelines include several recommendations for treating the disease that affects some 16 million Americans. The recommendations indicate that:

• The total amount of carbohydrates in meals or snacks is more important than the source or type.
• Sucrose (table sugar) and sucrose-containing foods do not need to be restricted.
• Non-nutritive sweeteners are safe when consumed within the acceptable daily intake levels estab-lished by the Food and Drug Administration.

Based on research from several clinical trials, the panel found that sucrose did not negatively affect glucose control to a greater extent than starch and other carbohydrate-containing foods. Instead of diabetics consuming sugar-laden foods, the panel recommends that sucrose-containing foods be replaced with carbohydrate sources such as fruits and vegetables. "As far as the carbohydrate-containing foods are concerned," Garg said, "it's best to use unrefined carbohydrates instead of sucrose. If you get your carbohydrates from fruits, vegetables and grains, then there are other beneficial substances that are not included in a package of sugar. If you compare the nutritional value of an apple to an equal amount of sugar, an apple would be more beneficial."

A dietary cholesterol intake of less than 300 milligrams a day also is recommended. Trans-unsaturated fatty acids - which are found in some margarines and formed when liquid, unsaturated oils are converted into a soft, semisolid fat by hydrogenation - should be minimized, according to the panel. Polyunsaturated fats, found in corn, sunflower, safflower and soybean oils, should account for 10 percent of caloric intake.
Another new component, implemented as a result of research conducted by Dr. Garg and his colleagues in the Center for Human Nutrition at UT South-western, is the inclusion of increased amounts of fiber in diabetics' diets. Last year Dr. Garg reported that a high intake of dietary fiber, mostly from fruits and vegetables, lowered blood glucose levels by 10 percent in study participants who consumed 50 grams of fiber in their daily diet. The high-fiber diet also decreased insulin in the blood and lowered blood lipid concentrations.

The panel recommends that diabetics choose a variety of fiber-containing foods, such as grains, fruits and vegetables. These foods provide vitamins, minerals and other substances essential for good health as well. "Research done in the Center for Human Nutrition at UT South-western has played a major role in guiding the principles of nutritional management in type 2 diabetics. Studies showing beneficial effects of monounsaturated fats and dietary fiber have had a major impact on the guidelines," Dr. Garg said. The new guidelines appeared in the January issue of Diabetes Care.