A high-stearic acid diet does not impair glucose tolerance and insulin sensitivity in healthy women

Results in epidemiological and experimental studies suggest that a diet rich in saturated fat may affect insulin sensitivity. However, no published data are available on the effect of stearic acid in this respect. Therefore, we examined the effects of a high-stearic acid diet and a high-oleic acid diet on glucose metabolism, serum lipids and lipoproteins, and blood coagulation factors in 15 healthy female subjects. Subjects followed the two experimental diets for 4 weeks according to a randomized crossover design. Both experimental diet periods were preceded by consumption of a baseline diet for 2 weeks. The diets provided 36% of energy (E%) as fat. In the experimental diets, 5 E% stearic or oleic acid was substituted for 5 E% of saturated fatty acids in the baseline diet. After the experimental diets, no differences were found in the insulin sensitivity index (mean +/- SEM, 5.4 +/- 1.9 v 5.2 +/- 1.6 x 10(-4) min(-1) . mu U-1 . mL(-1), nonsignificant [NS]), glucose effectiveness (0.026 +/- 0.006 v 0.026 +/- 0.003 min(-1), NS), or first-phase insulin reaction ([FPIR] 368 +/- 57 v 374 +/- 66 mU/L . min, NS). The concentration of serum lipids and lipoproteins and blood coagulation factors did not differ after the diet periods. In conclusion, a diet rich in stearic acid did not deteriorate glucose tolerance or insulin action in young healthy female subjects as compared with a diet rich in oleic acid. Copyright (C) 1998 by W.B. Saunders Company.