Comparison of the effects of a fish oil-containing diet, a diet containing an oil mixture based on the Iranian fat consumption pattern, and a standard diet on the serum glucose level and insulin sensitivity in rats

Information on the effects of different types of fat on insulin sensitivity is limited. The present study was designed to compare the effects of feeding a fish oil-containing diet, a diet containing an oil mixture based on the Iranian fat consumption pattern, and a standard diet from the fetal period till puberty on the serum glucose and insulin sensitivity in Wistar rats. Thirty female Wistar rats were randomly allocated to three dietary groups: a standard diet (containing soy bean-oil), a diet containing fish oil, and a diet containing an oil mixture based on the Iranian population fatty acid intake. Dams in each group were fed one of the diets during pregnancy and lactation, and in each case the pups born were weaned onto the same diet. Fasting serum glucose level (by photometry) and insulin (by ELISA) were measured in the pups and insulin sensitivity was calculated at puberty. Data were analyzed using SPSS software and the one-way ANOVA and Tukey tests. The fasting serum insulin level and insulin sensitivity in the fish oil-fed group were significantly lower (P=0.018) and higher (P=0.002), respectively, than in the other two groups. It seems a diet containing fish oil (rich in long chain omega-3 fatty acids) causes a higher insulin sensitivity, as compared to diets containing either soy bean oil (rich in omega-6 fatty acids) or mixed oil based on the Iranian dietary fatty acid pattern (rich in saturated fatty acids).