Diabetes occurs when the body has lost the ability to keep its glucose (blood sugar) level within the range that is needed for good health. Glucose is a form of sugar that is carried in the bloodstream, and it is the body’s primary fuel. Carbohydrate foods (sugars and starches) cause the level of glucose to rise in the body. Under normal circumstances, a proper balance is soon restored through the action of insulin, a hormone produced by the pancreas. However, if the body produces too little insulin, a person is said to have insulin-dependent diabetes mellitus (IDDM), and insulin injections are necessary. IDDM (frequently of childhood-onset) is an autoimmune disease in which the immune system destroys pancreatic cells. Some studies suggest that giving children dairy products in the first four months of life increases the risk of onset in genetically susceptible individuals; IDDM is rare in vegan children.
If the body becomes resistant to insulin, a person is said to have non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes. This form of diabetes may be caused by poor dietary habits. It is usually treated with a diet that emphasizes slow-releasing carbohydrates.
Although diabetes tends to run in families, being seriously overweight in middle age (especially around the waist) increases the risk of this disorder. It has also been found that new cases are twice as common among inactive people. Regular light exercise helps to improve the body’s ability to use its insulin.
There is no single diet that is appropriate for all diabetics. A carefully planned diet that is tailored to the individual’s needs should be prepared with expert advice. There are, however, some general dietary guidelines that can be followed to keep glucose levels under control, as well as to reduce the risk of heart disease, which is higher than normal for people with diabetes. Diabetics are advised to eat the kind of healthy diet that is recommended for most people: a high-fibre, high-carbohydrate diet that includes plenty of fruit, vegetables, pulses and whole grains, but limits sugar and fat. It is especially important for diabetics to watch their weight, as obesity increases the body’s resistance to insulin.
In order to keep glucose levels even, diabetics are usually advised to eat little and often (six small meals a day rather than three main meals), and to favour foods that produce small rises in glucose. Nutritionists once thought that sugary foods always produced a much sharper rise in glucose levels than starchy foods, but it is now known that some starchy foods, such as bread and potatoes, are capable of raising glucose levels just as quickly. This finding does not mean that diabetics should stop eating foods such as bread, but it does mean that sugar no longer needs to be completely excluded from the diet.
Good foods for a moderate glucose release include beans, lentils, pasta, noodles, oats and porridge; pulses and most fruit and vegetables are slow sugar releasers. The fibre found in whole grains, pulses, fruit and vegetables slows the intestinal absorption of sugar, helping to balance glucose levels.