Perhaps other omega3 oils are better than fish oil.
Nearly 12% of US adults have type 2 diabetes, a prevalence 25% greater than that reported only 20 y ago. Although the nation's battles with caloric overconsumption and obesity are largely to blame, some research suggests that a shift in the types of dietary fats might also be involved. Of particular interest is the well-documented inverse relation between fish oil consumption and diabetes risk. Not all research, however, is consistent in this regard, with some showing increasing risk with greater consumption of the long-chain, omega-3 fatty acids typically found in marine foods. Three independent studies, accompanied by a corresponding editorial by Edith Feskens from Wageningen University, published in the August 2011 issue of The American Journal of Clinical Nutrition
contribute new insight into how consumption of various omega-3 fatty acids might be related to diabetes risk.
Two of the investigations were conducted in Chinese populations—one using data from the Singapore Chinese Health Study (43,176 men and women), the other from the Shanghai Health Studies (116,156 men and women). Whereas the Singapore study related total omega-3, nonmarine-derived omega-3, and seafood-derived omega-3 intake with risk of diabetes, the Shanghai study compared intakes of various types of seafood and total omega-3 intake with diabetes risk. The third study, based in the United States, followed a cohort of adults (3088 men and women); blood concentrations of various seafood- and plant-based omega-3 fatty acids were studied in regard to their association with diabetes risk.
The Singapore study documented an inverse relation between plant-derived omega-3 intake, but not seafood-derived omega-3 intake, and risk of diabetes. Data from the Shanghai cohort suggested decreased diabetes risk with increased seafood intake, although the relation was stronger for women than men. Results from the US cohort suggested that several forms (marine and plant) of omega-3 fats were related to lower risk of diabetes.
In her accompanying editorial, Feskens queries, "in the prevention of type 2 diabetes: should we recommend vegetables oils instead of fatty fish?" Indeed, plant-based omega-3 fatty acids (such as alpha-linolenic acid, a dietary essential) have been shown in numerous studies to be as inversely related to diabetes risk, if not more so, as marine oils. She also urges additional research using fatty acid intake biomarkers and further investigation of the inherent interactions between genetics and diet on diabetes incidence and progression.