Insulin sensitivity after a reduced-fat diet and a monoene-enriched diet in subjects with elevated serum cholesterol and triglyceride concentrations

Background and Aims: To investigate the effect of a reduced-fat diet and a monoene-enriched diet (MUFA diet) on serum lipids, glucose and insulin meta bolism in subjects with elevated cholesterol and triglyceride concentration s. Methods and Results: Eighteen subjects with elevated serum cholesterol and triglyceride concentrations consumed the MUFA diet (39% of energy (E%) as f at and 21 E% monoenes) and the reduced-fat diet (34 E% fat, 16 E% monoenes) for 4 weeks according to a randomized cross-over design. Both periods were preceded by consumption of a standardized baseline diet for 2 weeks. Serum lipid and lipoprotein concentrations were determined at the beginning and end of each diet period. A frequently sampled intravenous glucose tolerance test was performed after the MUFA diet and the reduced-fat diet. Insulin s ensitivity index (S-I) was 40% higher after the reduced-fat diet than after the MUFA diet (2.42+/-0.42 vs. 1.73+/-0.24 10(-4) min(-1) U-1 ml(-1), p=0. 018). This change in insulin sensitivity was seen in 13 subjects and was mo st evident in those who began with the MUFA diet. Compared to the baseline diet (high in saturated fat), both experimental diets lowered serum total a nd LDL cholesterol concentrations (6.6-6.9%, p<0.05 and 7.4-8.0%, p<0.95 re spectively). Conclusions: Both diets were equally effective in lowering serum lipid conc entrations, but the reduced-fat diet resulted in better insulin sensitivity . Nutr Metab Cardiovasc Dis (2000) 10:177-187 (C) 2000, Medikal Press.