Long-term effects of fish oil on lipoprotein subfractions and low density lipoprotein size in non-insulin-dependent diabetic patients with hypertriglyceridemia

The effects of fish oil on lipoprotein subfractions and low density lipopro tein (LDL) size in non-insulin-dependent diabetes mellitus (NIDDM) patients with hypertriglyceridemia are unknown. To elucidate this, 16 NIDDM hypertr iglyceridemic patients (plasma triglyceride 2.25-5.65 mmol/l, plasma choles terol less than or equal to 7.75 mmol/l) were randomly assigned to a 6-mont h period with either moderate amounts of fish oil (n = 8) or placebo (n = 8 ) after 4 weeks of wash-out and 3 weeks of run-in. Diet and hypoglycemic tr eatment were unchanged throughout the experiment. LDL size were evaluated a t baseline and after 6 months. Three VLDL and LDL subfractions were measure d at the end of the two periods. The total lipid concentration of all very low density lipoprotein (VLDL) subfractions was lower at the end of fish oi l treatment compared with placebo (large VLDL 124.3 +/- 19.7 mg/dl vs 156.7 +/- 45.5 mg/dl; intermediate VLDL 88.5 +/- 9.5 mg/dl vs 113.9 +/- 23.2 mg/ dl; small VLDL 105.9 +/- 19.7 mg/dl vs 128.9 +/- 40.7 mg/dl) (mean +/- SEM) , although the difference was not statistically significant. Moreover, at t he end of the two treatments, the percentage distribution of VLDL subfracti ons was very similar (large 37.5 +/- 3.3% vs 37.6 +/- 2.6%, intermediate 37 .6 +/- 0.9% vs 31.0 +/- 2.4%; small 34.9 +/- 3.7% vs 31.4 +/- 2.1%). Concer ning LDL, no significant change in LDL size was observed after the two trea tments (255.4 +/- 2.2 Angstrom vs 254.2 +/- 1.7 Angstrom, fish oil; 253.7 /- 2.0 Angstrom vs 253.3 +/- 1.7 Angstrom, placebo). LDL subfraction distri bution was also very similar (large 17 +/- 3% vs 17 +/- 2%; intermediate 62 +/- 3% vs 65 +/- 3%; small 21 +/- 3% vs 18 +/- 2%), at the end of the two periods, confirming the lack of effects on LDL size. In conclusion, our stu dy indicates that in NIDDM patients with hypertriglyceridemia, fish oil doe s not induce any improvement in LDL distribution and LDL size despite its p ositive effects on plasma triglycerides. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.