Mori T A, Bao D Q, Burke V, Puddey I B, Watts G F, Beilin L J
Department of Medicine, The University of Western Australia, Perth, Australia.
Am J Clin Nutr. 1999 Nov;70(5):817-25. doi: 10.1093/ajcn/70.5.817.
Obesity in hypertensive patients is associated with dyslipidemia and insulin resistance, both of which are improved by weight control. n-3 Fatty acids have diverse effects on mechanisms underlying atherosclerosis, including a decrease in serum triacylglycerols and an increase in HDL(2) cholesterol.
The objective was to examine whether dietary fish enhances the effects of weight loss on serum lipids, glucose, and insulin in 69 overweight, treated hypertensive patients.
Overweight patients being treated for hypertension were randomly assigned to either a daily fish meal (3.65 g n-3 fatty acids), a weight-loss regimen, the 2 regimens combined, or a control group for 16 wk.
Sixty-three subjects completed the study. Weight decreased by a mean (+/-SEM) of 5.6 +/- 0.8 kg with energy restriction. Weight loss decreased fasting insulin (P = 0.003) and the area under the curve for insulin (P = 0.003) and glucose (P = 0.047) during an oral-glucose-tolerance test. The greatest decrease occurred in the fish + weight-loss group. There was no independent effect of fish on glucose or insulin. Fish increased HDL(2) cholesterol (P = 0.004) and decreased HDL(3) cholesterol (P = 0.026) without altering total, LDL, or HDL cholesterol. Weight loss had no effect on these variables. Fasting triacylglycerols fell significantly with fish consumption (29%) and weight loss (26%). The fish + weight-loss group showed the greatest improvement in lipids: triacylglycerols decreased by 38% (P < 0.001) and HDL(2) cholesterol increased by 24% (P = 0.04) compared with the control group.
Incorporating a daily fish meal into a weight-loss regimen was more effective than either measure alone at improving glucose-insulin metabolism and dyslipidemia. Cardiovascular risk is likely to be substantially reduced in overweight hypertensive patients with a weight-loss program incorporating fish meals rich in n-3 fatty acids.
