Abstract

Essential fatty acids (EFAs) are required for the normal structure of all membranes, for cholesterol transport, for the maintenance of normal permeability barriers and as precursors of eicosanoids. The main EFA in the diet is linoleic acid (LA) but in order to be utilized effectively it must be converted to gamma-linolenic acid (GLA) and to further metabolites. The formation of GLA is impaired in diabetes, leading to deficits of EFA metabolites required for membrane structure and as precursors of cell-regulating molecules. This partial block may be an important factor in the development of long-term complications of diabetes. The block could be overcome either by feeding large amounts of LA or by the administration of GLA directly. Both strategies have been used successfully. Several studies have demonstrated the value of EFA supplementation in controlling diabetic cataract, diabetic retinopathy and diabetic cardiovascular complications. Diabetic neuropathy is a major clinical problem. Around 50% of people with diabetes will eventually develop clinical symptoms attributable to neuropathy. On neurophysiological testing over 90% of long-term diabetics show evidence of nerve damage. While good diabetic control may slow down development of the problem, many patients who are well-controlled still develop severe neuropathy. There is, therefore, a pressing need for new therapies. Several new approaches to treatment, notably the aldose reductase inhibitors and gamma-linolenic acid, are currently being investigated. This book reviews the clinical problem of diabetic neuropathy and discusses the new treatment methods, with particular reference to gamma-linolenic acid. Many of the leading experts, both in clinical diabetes and in basic science, have contributed to the volume. (Publisher's summary)