Functional foods for diabetics

One of a growing number of products known as "functional" or "medical" foods are being formulated to address the nutrition concerns of people with diabetes. These products are developed to meet society’s demand for convenience, portability, and good taste. At the same time, they are promoted as healthy foods that help people with diabetes manage their disease by improving glycemic control and lowering risk factors for long-term complications.

Many of the diabetes medical foods entering the marketplace are modified, enhanced, fortified, or supplemented in order to confront diabetes from a number of directions. The challenge is to evaluate each of these products and assess the contribution each makes to patients’ overall nutrient intake. Diabetics need to be offered guidance about how they may integrate these products into an eating plan that achieves their goals for diabetes medical nutrition therapy.

Diabetes Medical Foods

Physiologically active food components play a role in improving glycemic control and reducing risk factors for development of diabetes complications. Functional features in these products include resistant starch and added fiber, fortification with vitamins and minerals—specifically, notably high amounts of the antioxidant vitamins C and E and chromium. Some products manipulate the percentages of the macronutrients, carbohydrate, protein, and fat, while others incorporate herbal and other nontraditional remedies.

In evaluating each product, it is important to determine whether there is sufficient evidence to support its desired role in diabetes management and whether the inclusion of a functional feature is truly efficacious.

Resistant starch and soluble fiber

Nutritionists note that the total amount of carbohydrate consumed is more important than the source of carbohydrate. However, various starches are known to cause different glycemic responses.

Resistant starch withstands breakdown by digestive enzymes and thus is digested and absorbed at a slow and sustained rate. This results in a coinciding low post-meal blood glucose peak and a continued slow release of glucose into the bloodstream for several hours. As a result of this, resistant starch, either in the form of uncooked cornstarch or produced through food processing, is a key functional feature of diabetes foods.

Benefits of resistant starch includes:

• lowering of insulin response
• improvement in insulin efficiency in the post-meal phase
• improvement in lipid metabolism
• improvement in fibrinolytic capacity ( treatment involving breaking of clots that help in the flow of blood to the heart muscle)

Fiber fortification, is another feature of functional foods available for diabetics. All individuals, including those with diabetes, are encouraged to consume 20–35 g/day of fiber from both soluble and insoluble sources. Individuals who have restricted calorie intakes may be especially vulnerable to an inadequate fiber intake. Although we must encourage consumption of a variety of fruits, vegetables, and whole grains, supplemental foods can be additional fiber sources.

Some well-known features of high-fiber diets include:

• Lowering of postmeal blood glucose rise
• Improvement of insulin sensitivity
• Reduction of hyperinsulinemia,
• Reduction of total cholesterol by more than 5% and reduction of LDL cholesterol
• Lowering of triglyceride levels
• Favorable affect on clotting factors.

Protein and fat

The mix of protein and fat in diabetes supplements serves the functional purpose of improving glycemic control and reducing cardiovascular risk factors.

Fat is added to diabetes formula foods for the following reasons:

• Prevention of hypoglycemia as fat delays gastric emptying.
• Slowing the absorption of carbohydrate, thereby delaying the post-meal blood glucose peak.
• Lowering the risk of hypoglycemia by extending the nutrient absorption time and entrance into the bloodstream as glucose.

A low-carbohydrate, high-protein diet trend has been popular and due to this the ideal dietary protein mix is a much debated subject.

However, nutrition recommendations for people with diabetes advise that 10–20% of daily calories should come from protein. The percentage of protein in some snacks and foods designed for people with diabetes is as high as 30% of calories, whereas carbohydrate provides only 40% of calories in these products.

The important functions of proteins with respect to a diabetic snack or functional foods, although are considered to:

• lower glycemic index
• prevent high glucose excursions
• decrease insulin levels
• reduce fat storage
• reduce hunger
• improve weight-loss success and glycemic control.

Vitamins, minerals, and antioxidants

A number of studies have indicated that oxidative processes are involved in the development of atherosclerotic diseases, and antioxidants, especially vitamin E, play a role in lowering disease risk. Chromium supplementation is gaining popularity as its potential to improve insulin action, improve fasting and postprandial blood glucose, and reduce blood lipids gains acceptance. B vitamins, especially folic acid, are recognized to play a role in reducing homocysteine levels and may be beneficial in the prevention and treatment of vascular complications of diabetes. In the light of these findings, these are being added to functional foods for diabetics.

However, diabetics need to be cautioned about excess intake of these foods. Diabetes snacks and beverages can potentially contribute significant amounts of these nutrients to the total daily intake. Individuals with diabetes, either on their own or by advice of their physician, may also be supplementing these same vitamins and minerals in addition to consuming other highly fortified foods.

Diabetics need to keep the following points in mind regarding the consumption of functional foods

• Diabetes supplemental foods can be beneficial when appropriately incorporated into a diabetes meal plan but should not be routinely used as meal replacements.
• Other snack bars, most containing uncooked cornstarch, are formulated to prevent hypoglycemia, especially at night. Their intended use is as part of a bedtime snack or as a snack to be taken before or after exercise. These products may be especially helpful to patients on intensive insulin therapy who are susceptible to hypoglycemia, particularly those with hypoglycemia unawareness.
• Diabetes snacks and beverages available as functional foods are not appropriate treatments for hypoglycemia as they are formulated to cause a reduced or delayed rise in blood glucose. If an immediate-acting source of carbohydrate is needed, a conventional snack bar or other carbohydrate source that is quickly absorbed and causes a rapid blood glucose rise should be used.
• Self-monitoring of blood glucose and careful record keeping will enable clinicians and people with diabetes to determine the effects of snack bars or beverages on blood glucose levels. Because each diabetes bar or beverage has a unique formulation, its glycemic effect may also be unique.