Will DHA increase blood sugar levels and lower glucose tolerance in a person who is pre-diabetic?

Two extensive reviews based on the various clinical trials published on this topic have appeared recently. In their review, Drs. Nettleton and Katz (J. Am Dietetic Assoc., 105:428-440 (2005)) concluded that controlled clinical studies have shown that consumption of the long-chain omega-3 fatty acids from fish/fish oils as DHA/EPA (combined) exhibit cardioprotective effects in person with type 2 diabetes ‘without adverse effects on glucose control and insulin activity’. They also mention the various benefits in such patients including apparent lower risk of primary cardiac arrest, reduced cardiovascular mortality (particularly sudden cardiac death) and the favorable effects on blood triglyceride levels and other risk factors for cardiovascular disease. They consider the favorable effects to outweigh the modest increase in low-density-lipoprotein-cholesterol levels that may result in some patients on increased intakes of DHA/EPA. The authors also make reference to preliminary evidence suggesting that increased consumption of DHA/EPA along with reduced intakes of saturated fats may reduce the risk of conversion from impaired glucose tolerance to type 2 diabetes in overweight persons. A very recent review of this topic by Dr. Edward Barre (J. Oleo sci., 56:319-325 (2007)) concluded that DHA/EPA consumption appears to significantly benefit metabolic syndrome and type 2 diabetes particularly in terms of hypertriglyceridemia and platelet aggregability with potential but somewhat less established impacts on blood pressure, oxidative state, and inflammation.