Nutrition and Diets for treating diabetes
Diabetic diets changed greatly throughout the 20th century. They have undergone further change since about 1970, as several facts emerged:
Oral hypoglycaemic drugs may predispose to heart disease.
There is no evidence that eating sugar causes diabetes.
Asian people with diabetes on high starch diets have fewer complications (especially atherosclerotic) than their counterparts in Western Europe and North America.
Westerners with diabetes are dying of excess atherosclerotic disease, have higher plasma cholesterol values, and have been eating higher saturated fat diets than people with no diabetes.
Viscous dietary fibres such as that in guar, pectin, and legumes (though carbohydrates) improve diabetic control.
Increased dietary carbohydrate improves the response to a glucose tolerance test. Increasing the (complex) carbohydrate of diabetic diets is not usually followed by
Individual foods containing carbohydrate do not give the same glucose and other metabolic responses at a standard intake. When put to the test, in human subjects some foods give much higher blood glucose curves than others. They have a higher or lower glycaemic index (area under the 2-hour blood glucose curve after eating a food containing 50 g carbohydrate as percentage of the corresponding area after the same weight of glucose). This means that carbohydrate exchange lists can no longer be relied on. (It was always hard to believe that 2 oz of grapes had the same effect in the body as 7 oz of whole milk.) The main cause of a low glycaemic index is that the starch in some foods is digested slowly by pancreatic amylase.
Diabetics also have an increased chance of developing hypertension. The sodium content of their diets has been largely ignored.
Principles of dietary treatment for diabetes
Type 1: insulin dependent diabetes (IDD):
Integrate and synchronise meals (that is, the metabolic load) with the time(s) of action of the insulin treatment to minimise high peaks of blood glucose as well as episodes of hypoglycaemia. It is recommended that the individualís usual food intake is used as a basis for integrating insulin therapy into the eating and exercise patterns. Patients on insulin therapy should eat at consistent times synchronised with the time-action of the insulin preparation used.
Reduce saturated fat to 10% of total energy or less. People with diabetes have an increased risk of coronary heart disease and this dietary change may reduce it.
Keep salt intake low, because people with diabetes have an increased risk of hypertension.
Be very moderate with alcohol. Large intakes carry the risk of hypoglycaemia; irregular drinking can disturb glycaemic control. But regular 1 to 2 glasses with a meal are acceptable and might be beneficial (except in pregnancy).
If still growing make sure intakes of essential nutrients are adequate.
Type 2: non-insulin dependent diabetes (NIDD) :
Dietary change has a greater potential to improve type 2 diabetes.
Reduce body weight by eating fewer kilojoules and taking regular exercise, and keep at it! Even modest losses of weight improve metabolic control. About three-quarters of
type 2 diabetics are overweight or obese, and weight reduction is the first line of dietary management. To help patients lose weight and keep it off is a challenge for the physician and dietitian. Diabetics have a stronger incentive to lose weight because this improves
their disease as well as their figure, but sulphonylureas or insulin (not metformin) tend to stimulate appetite. Some who succeed in losing weight may be able to go off medications or go off insulin.
Reduce saturated fat. Increased LDL-cholesterol may be more pathogenic in type 2 diabetes than non-diabetic people.
Emphasise low glycaemic index foods.
Increase intake of vegetables, fruit, legumes, and whole grain cereals (which increase fibre intake and mostly have low glycaemic indices).
Keep salt intake low.
Avoid excess alcohol but 1-2 drinks per day with meals are acceptable.
Forget carbohydrate exchanges.
There is no need to be obsessional about reducing sucrose. The glycaemic effect of sucrose is about the same as that of most starchy foods.
Foods that have been shown to have low glycaemic indices (55 or less) compared to glucose = (100) ^12
Soya beans (18)
Pearl barley (28)
All pastas (40-45)
Dried peas (31)
Rolled oats (55)
Apple juice (36)
Canned baked beans (40)
Oat bran (50)
Frozen peas (boiled) (48)
All Bran (40)
Other dried legumes, (around 30)
Pumpernickel (rye) bread (41)
Orange juice (57)
Milk (full cream or low fat) and yoghurt (25-35)
The glycaemic index of glucose is 100, of fructose 20, of sucrose (half way between) 60, of lactose 45.