Effect of dietary fish and exercise training on urinary F-2-isoprostane excretion in non-insulin-dependent diabetic patients

Despite the potential benefits of dietary treatment with marine omega 3 fat ty acids in cardiovascular disease, there remains concern with respect to t heir potential for increased lipid peroxidation. Thus far, data from in viv o studies are inconclusive. Increased lipid peroxidation has also been asso ciated with acute exercise in some studies, but the methods have been nonsp ecific. The quantitation of F-2-isoprostanes provides a more reliable and u seful assessment of in vivo lipid peroxidation. We therefore aimed to asses s the independent and combined effects of dietary omega 3 fatty acids and a erobic exercise training on urinary F-2-isoprostane levels in dyslipidemic non-insulin-dependent diabetic (NIDDM) patients. In a randomized controlled trial, 55 untrained, sedentary, dyslipidemic NIDDM patients were randomly assigned to a low-fat diet (30% of daily energy) with or without one daily fish meal (3.6 g omega 3 fatty acids per day) and further randomized to eit her a moderate (55% to 65% maximal oxygen consumption [(V) over doto(2)max] ) or light (heart rate <100 bpm) exercise training program for 8 weeks. Twe nty-four-hour urine samples from 49 subjects were collected for measurement of urinary F-2-isoprostanes by gas chromatography-mass spectrometry before and after intervention. The fish diets reduced urinary F-2-isoprostanes by 830 +/- 321 pmol/24 h (20%, P = .013) relative to the low-fat diet alone. This effect was independent of age, gender, and body weight change. Moderat e exercise training did not alter F2-isoprostanes. These findings show that , at least in the short-term, exercise had no effect, whereas the inclusion of regular fish meals as part of a low-fat diet reduced in vivo lipid pero xidation in dyslipidemic NIDDM patients. This response could further comple ment the known benefits of omega 3 fatty acids and exercise favoring a redu ced cardiovascular risk in diabetic patients. Copyright (C) 1999 by W.B. Sa unders Company.