Abstract

In diabetes, two different defects in essential fatty acid metabolism have been identified. The first is a reduced rate of desaturation at both the delta-6- and delta-5-desaturase levels leading to reduced formation of the long-chain derivatives of dietary omega-6 and omega-3 fatty acids. The second is a reduced rate of incorporation of highly unsaturated fatty acids into phospholipids in cell membranes. These defects are compounded by increased oxidative stress which leads to further damage to essential fatty acids. These changes probably contribute to complications of diabetes such as neuropathy. In animal and human studies, by-passing the first omega-6 delta-6-desaturation step by providing gamma-linolenic acid has been shown consistently to improve diabetic neuropathy. More recently it has been found that the therapeutic efficacy of gamma-linolenic acid can be dramatically enhanced by combining it with an antioxidant such as ascorbic acid or alpha-lipoic acid. These findings point the way forward in the management of diabetic complications.