High fibre diet improves blood sugar in diabetes

A high fibre diet can improve glycaemic (blood sugar) control in individuals with type II (adultonset) diabetes.

Although small, a recent study adds weight to nutritionists' long time claim that fibre is an effective way to control blood sugar (N Engl J Med, 2000; 342: 1392-8).

A US team studied the effect of diets containing differing amounts of fibre in a group of 13 patients with type II diabetes. For the first six weeks, the study participants were put on a diet containing a moderate amount of fibre 24 g total daily, of which 8 g was soluble and 16 g insoluble fibre. This is the diet recommended by the American Diabetes Association (ADA).

They were then put on a high fibre diet (50 g daily with 25 g of soluble and 25 g of insoluble fibre) for a further six weeks. Researchers compared the effects of the diets on glycaemic control and blood fat concentration.

What they found was that, compared with the ADA diet, the high fibre diet lowered blood sugar levels by 8.9 per cent and 24 hour plasma insulin levels by 12 per cent. The high fibre diet also lowered levels of harmful LDL cholesterol without altering levels of the more beneficial HDL cholesterol.

Total cholesterol levels were 6.7 per cent less while on the high fibre diet, and gastrointestinal absorption of cholesterol was l0 per cent less.

The researchers attribute much of the improvement in the study group to the high level of soluble fibre included in the high fibre diet.

The high level of fibre in the diet was achieved using foods in their natural state and not those which had been fortified with extra fibre. Perhaps because the study participants were eating 'normal' food, compliance with the high fibre diet was high, suggesting that such dietary changes could easily be incorporated into the lives of diabetics.