For some time now the search has been on for slow release carbohydrate foods, or lente carbohydrate, which would help diabetic patients to reduce postprandial glucose surges and the need to secrete large amounts of insulin. Such foods would be classed as low glycemic index. Recently, investigators looking at children with glycogen storage disease have demonstrated that a newly developed starch, which appears to have slower release characteristics in the small intestine, also effectively treats glycogen storage disease by maintaining blood glucose levels for longer than conventional starch therapy (Correia EC et al Am J Clin Nutr 2008;88:1272-6).

In glycogen storage disease, impaired glucose-6-phosphates activity results in limited endogenous hepatic glucose production and often severe hypoglycemia 3-4 hours after a meal. Blood glucose falls under the action of insulin, and the liver fails to respond to maintain levels. Kids with this condition have to be woken 1-3 times each night and provided with carbohydrate in the form of uncooked corn starch. Failure to prevent the fall in blood sugar may result in CNS damage.

But the recent discovery of an apparently slower release starch appears to maintain children’s blood glucose levels above 60 mg/dl for 6 hours, an hour longer than conventional treatment. A further 60 minutes of continuous sleep represents a real advantage. The researchers also showed that with the new starch formulation over 30% of patients could last for 10 hours with blood glucose levels of > 60 mg/dl, compared to about 18% on current therapy.

Hope for diabetics

In diabetes, too, the search is on for slow release carbohydrate foods with a low glycemic index. Again, the aim has been to reduce post-prandial fluctuations in blood glucose and so limit glycation of Hb which has been linked to the microvascular complications of diabetes. The low glycemic index foods selected for diabetes treatment have included beans, peas and lentils, which contain the slowly digested starch amylose. The commercially produced so-called “resistant” starches often behave more like fibre. Their “resistant” component is completely malabsorbed i.e. enters the colon where it’s fermented to short chain fatty acids and absorbed.

The present testing of a novel slowly digested starch (rather thanone that’s absolutely resistant to digestion) is therefore of great interest not only to treat glycogen storage disease but also for the treatment of type 2 diabetes, and possibly to reduce nocturnal hypoglycemia in type 1. The idea of slow release starch has come full circle, from the treatment of diabetes to that of glycogen storage disease and now hopefully back to diabetes.