Diabetes Mellitus - Dietary Management

DIETARY MANAGEMENT

Diabetes can be treated by diet alone, or diet and hypoglycaemic drugs or diet plus insulin depending on the type and severity of the condition.

The main modes of treatment of diabetes are:

1.     Diet

2.     Exercise

3.     Drugs

4.     Education

Objectives in the management of diabetes are to:

1.     Reduce the sugar in blood and urine

2.     Maintain ideal body weight

3.     Treat the symptoms

4.     Reduce serum lipids

5.     Provide adequate nutrition

6.     Avoid acute complications

7.     Prevent vascular complications

Diabetic diet need not be a complete deviation from the normal diet. Indian diets are generally high in carbohydrate and low in fat, with carbohydrates providing 60 - 65% of total calories and fat providing 15 - 25% of total calories. The rest of the calories 15-20% is derived from proteins. The nutrient content of a diabetic diet has to be planned based on the age, sex, weight, height, physical activity and physiological needs of the patient. Diet for a diabetic can be planned using

1.     Food exchange lists and

2.     Glycaemic index of foods.

1. Food exchange lists

The diet for a diabetic patient is prescribed in terms of exchange lists. Food exchange lists are groups of measured foods of the same caloric value and similar protein, fat, carbohydrate and can be substituted one for another in a meal plan. None of the exchange groups can itself supply all the nutrients needed for a balanced diet.

A balanced diet is one in which all the five food groups are included in required amounts in order to meet the recommended dietary allowances for individuals.

The food exchange lists help the patient to restrict the foods intake according to the insulin prescription so that hyperglycemia and hypoglycaemia can be prevented and to have variety in the diet.

2. Glycaemic Index

The glycaemic index indicates the extent of rise in blood sugar in response to a food in comparison with the response to an equivalent amount of glucose. The ability of the food item to raise the blood sugar is measured in terms of glycaemic index.

Glycaemic Index = (Blood glucose area of test food/Blood glucose area of reference food) x 100

Factors that affect the glycaemic response to food are

1.     Rate of ingestion of food

2.     Food form

3.     Food components - fat content, fibre content, protein content.

4.     Method of cooking and processing food.

The glycaemic index is therefore useful in planning diet for diabetics. Cereals like wheat, rice, root vegetables like potato and carrot have a high glycaemic index (65 - 75%). Fruits have an intermediate glycaemic index (45 - 55%) and legumes have a low glycaemic index (30 - 40%) and are hence beneficial to diabetics.

The ability of the food item to raise the blood sugar is measured in terms of glycaemic index. Since the blood sugar level depends mainly on the intake of carbohydrate it is important to distribute the intake of carbohydrates. The total amount of carbohydrates is divided in to 4-5 equal parts. One third (33%) is served during lunch, one third (33%) during dinner. Of the remaining one third (33%), 25% is served during breakfast and 9% at tea or bed time.

Energy

The calculated calorie requirement should allow the patient to lose or gain weight as required and maintain body weight 10% lower than the ideal / desirable body weight. Dietary calories should be 60 - 70 per cent from carbohydrate 15 - 20 per cent from protein and 15 - 25 percent from fat.

The recommended calorie intake for a diabetic based on body weight is as follows : over weight individual - 20 kcal / kg.wt/day. ideal weight - 30 kcal / kg.wt./day. underweight - 40 kcal / kg.wt/ day.

Carbohydrate

High carbohydrate high fibre diet is given as it improves insulin binding. Complex carbohydrate found in cereals and pulses are given. These are then broken down into simple sugars before they are absorbed from the gut. Refined carbohydrates such as sugar, honey, jaggery and jam contain simple sugars which are directly absorbed are not recommended for diabetics, as they cause a rapid rise in blood sugar. Sugar present in fruits and milk raise the blood sugar at a slightly lower rate. Whole apple is better than apple juice because of its high fibre content and low glycaemic index.

Protein

It is recommended that 15 - 20% of total calories be derived from proteins. Proteins supply essential amino acids needed for

tissue repair. Proteins do not raise blood sugar during absorption and do not supply as many calories as fats.

In patients with NIDDM, consumption of protein along with carbohydrate will lower the blood glucose concentration. One gram of protein per kilogram body weight is adequate.

Fat

Low fat diet increases insulin binding and also reduces LDL and VLDL levels and reduces the incidence of atherosclerosis which is more common in diabetics. Fat content should be 15 - 25% of total calories and higher in polyunsaturated fatty acids.

Vitamins and Minerals

These are protective factors which are essential for the body. They are present in fruits, and vegetables.

Dietary fibre

Intake of 25g of dietary fibre per 1000 calories is considered optimum for a diabetic. High fibre foods have a low caloric value and low glycaemic index and therefore diabetics should consume such foods liberally. Fibre present in vegetables, fruits, legumes and fenugreek seed is soluble in nature and more effective in controlling blood sugar and serum lipid than insoluble fibre present in cereals.

High fibre diets

1.     Promote weight loss

2.     Lower insulin requirements

3.     Decrease serum cholesterol and triglyceride values and lower blood pressure.

Other dietary guidelines to be remembered are.

1.     Timely intake of in between meal snacks should be stressed to avoid hypoglycaemia.

2.     Patients should avoid fasting and feasting.

3.     Alcohol , makes a person obese and stimulates appetite. The diabetic should avoid alcohol.

Diabetic Diet

This diet is as close to the normal diet as possible so as to meet the nutritional needs and the treatment of the individual patient. This diet is slightly low in carbohydrates, but adequate in other food principles.

Exercise

Regular exercise should be an integral part of the daily routine of the diabetic.

Benefits of exercise for Diabetics

1. Metabolic effects : Exercise Increase

1.     Insulin sensitivity

2.     Oxidative enzymes

3.     Amino acid uptake

4.     Storage of glycogen

5.     Maximal oxygen uptake

2. Cardio vascular effects

1.     Decrease in triglycerides

2.     Increase in HDL - Cholesterol

3.     Lower resting Blood pressure

4.     Increase in oxygen transport (decreases blood viscosity)

5.     Increases stroke volume and increases cardiac output

Drugs

In NIDDM, the body produces insulin, but this is less effective in controlling high blood sugar levels. When diet, exercise and weight reduction are not enough to control high blood sugar, oral hypoglycemic drugs are given. There are two groups of drugs used - sulphonylureas and biguamides. Since the action of these two drugs are different the doctor has to decide which is suitable.