A high-trans fatty acid diet and insulin sensitivity in young healthy women

Epidemiological and experimental studies suggest that a diet rich in satura ted fat affects insulin sensitivity. Monoenes and dienes that have an usatu rated bond with the trans configuration (trans fatty acids) resemble satura ted fatty acids with respect to structure, but no published data are availa ble on the effect of trans fatty acids on insulin sensitivity. Therefore, t he effects of diets high in trans fatty acids (TFA diet) and oleic acid (mo nounsaturated fat [MUFA] diet) on glucose and lipid metabolism were studied in 14 healthy women. Subjects consumed both experimental diets for 4 weeks according to a randomized crossover study design. Both experimental diet p eriods were preceded by consumption of a standardized baseline diet for 2 w eeks. The diets provided 36.6% to 37.9% of energy (E%) as fat. In the TFA d iet, there was 5.1 E% trans fatty acids, and in the MUFA diet, 5.2 E% oleic acid, substituted for saturated fatty acids in the baseline diet. A freque ntly sampled intravenous glucose tolerance test (FSIGT) was performed at th e end of the experimental diet periods. Glucose effectiveness (S-G) and the insulin sensitivity index (S-l) did not differ after the two experimental diet periods. There was also no difference in the acute insulin response be tween the diets. The total cholesterol to high-density lipoprotein (HDL) ch olesterol ratio and serum total triglyceride, HDL, and low-density lipoprot ein (LDL) triglyceride and apolipoprotein B (apoB) concentrations were high er (P <.05) after the TFA diet. In conclusion, in young healthy women, the IFA diet resulted in a higher total/HDL cholesterol ratio and an elevation in triglyceride and apo B concentrations but had no effect on glucose and i nsulin metabolism compared with the MUFA diet. Copyright (C) 1999 by W.B. S aunders Company.