Nutrition Therapy for Diabetes
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Nutrition Therapy for Diabetes |
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The American Diabetes Association's 1994 nutrition recommendations for people with diabetes provides a new model for the dietary treatment of diabetes. The Diabetes Control and Complications Trial has demonstrated the benefits of tight serum glucose control and the effectiveness of individualized nutrition therapy in achieving glycemic control.
The new model, called medical nutrition therapy for diabetes, stresses a four-pronged approach that includes assessment of the individual's metabolic and lifestyle parameters, identification of nutrition goals, an intervention designed to achieve these goals, and evaluation to determine therapeutic outcomes.
Blood glucose and lipid goals join weight and blood pressure goals as the focus of medical nutrition therapy for overweight individuals with NIDDM. Although weight loss and low calorie diets improve blood glucose levels over the short term, they have not been effective in maintaining weight loss over the long term. Therefore, when weight loss can't be maintained, emphasis should be placed instead on glucose and lipid goals.
The American Diabetes Association recommends that protein provide 10 to 20 percent of total calories, which is consistent with the protein intake of the general public. A protein intake similar to the RDA of 0.8 gm/kg, or about 10 percent of total calories, is recommended for individuals with evidence of nephropathy.
The new guidelines recommend a specific amount of saturated fat (less than 10 percent of calories), and polyunsaturated fat (up to 10% of calories), but do not recommend a specific amount of total fat. Thus, the ratio of carbohydrate to fat will vary among individuals.
The recommended fat intake for an individual patient depends on glucose, lipid, and weight goals. Diabetics who have normal lipids and a healthy weight can follow the Dietary Guidelines for Americans in which fat supplies no more than 30% of calories, saturated fat supplies less than 10% of calories, and dietary cholesterol supplies no more than 300 mg/day.
A diabetic with an elevated low-density lipoprotein can follow the National Cholesterol Education Program step 2 diet, in which saturated fat supplies less than 7% of calories, total fat supplies no more than 30% of calories, and dietary cholesterol supplies less than 200 mg/day.
A diabetic with high triglycerides and very-low-density lipoproteins may want to avoid a high carbohydrate diet, although saturated and polyunsaturated fat should each provide less than 10% of total calories. A moderate increase in monounsaturated fat (up to 20% of calories) is one way to reduce saturated fat without increasing carbohydrate.
If obesity and weight loss are the primary issues, reducing total fat intake is an effective way to reduce calorie intake and body weight, particularly when combined with exercise. A low-fat diet need not be a high carbohydrate diet. Absolute fat intake can be decreased without changing carbohydrate or protein. This will result in a low calorie diet compared to the original diet and facilitate weight loss.
Diabetics, as the general public, can include sucrose as part of their total carbohydrate intake. The most widely held belief about the dietary treatment of diabetes is that sucrose should be avoided and replaced with complex carbohydrates. It is assumed that sugars are more rapidly digested and absorbed than are complex carbohydrates, and thereby increase serum glucose to a greater extent.
This belief is unfounded. Fruits and milk have a lower glycemic response than most starches (e.g. bread, rice, and potatoes), and sucrose has a glycemic response similar to that of most starches. Although various starches do have different glycemic responses, from a clinical perspective first priority should be given to the total amount of carbohydrate consumed, rather than the source of the carbohydrate. Also, from a practical standpoint, it's unreasonable to expect diabetics to avoid sucrose and sweets on a long term basis.
The usual amount of fructose in the diet, such as found in fruits and vegetables, is acceptable for diabetics. However, consuming twice the usual amount of fructose can adversely effect a diabetic's cholesterol level. This is usually due to excessive consumption soft drinks or sweets (rather than fruit and fruit products), and can be corrected by moderating intake.
The 1994 recommendations for dietary fiber are the same for people with or without diabetes -- 20 to 35 gm per day. Americans in general should increase their fiber intake by eating more beans, whole grains, vegetables, and fruits. Diabetics who increase their fiber intake should monitor their plasma glucose and lipids, then reevaluate their therapy. A soluble fiber supplement should be considered before lipid-lowering medication is prescribed.
1. American Diabetes Association. Nutrition recommendations and principles for people with diabetes mellitus. Diabetes Care. 17: 519-522, 1994.
2. The DCCT Research Group. Nutrition interventions for intensive therapy in the Diabetes Control and Complications Trial. J. Am. Diet. Assoc. 93: 765-772, 1993.
3. Tinker LF, Heins JM, and HJ Holler. Commentary and translation: 1994 recommendations for diabetes. J. Am. Diet. Assoc. 94: 507-511, 1994.
Ellen Coleman,
RD, MA, MPH
ellen@cruciblefitness.com
