High-Fat Diet-Induced Hyperglycemia and Obesity in Mice: Differential Effects of Dietary Oils.
High-Fat Diet-Induced Hyperglycemia and Obesity in Mice: Differential Effects of Dietary Oils.
Year: 1996
Authors: S Ikemoto, M Takahashi, N Tsunoda, K Maruyama, I Itakura, O Ezaki.
Publication Name: Metabolism
Publication Details: Volume 45; Number 12; 1539.
Abstract:
Data supports the relationship between genetic and environmental factors and the onset of non-insulin-dependent diabetes mellitus (NIDDM). A high fat diet has been shown to be a causative agent in obesity-induced insulin resistance. Both MUFAs and n-3 PUFAs have been reported to have favorable effects on NIDDM. Mice fed a high-fat diet typically develop hyperglycemia and obesity and are therefore a good model to use to study the effects of diet on NIDDM. Using a NIDDM mouse model, the effects on glucose metabolism of seven different dietary oils with various FA profiles were assessed in this study. The oils included palm oil, which contains mainly 45% palmitic acid (C16:0) and 40% OA (C18:1); lard oil, 24% palmitic and 44% OA; canola oil, 59% OA and 20% LA (C18:2); soybean oil, 24% OA and 54% LA; safflower oil, 76% LA; perilla oil, 58% ALA; and tuna fish oil, 7% EPA and 23% DHA. C57BL/6J mice received each oil as part of a high-fat diet (60% of total calories) for 19 weeks. After the feeding period, the authors reported the following body weight pattern induced by the diets: soybean > palm >/= lard >/= canola oil>/= safflower >/= perilla > fish oil. N-3 PUFA intake was found to be inversely correlated with obesity. Blood glucose levels, 30 minutes after a glucose load, were highest for safflower oil, modest for canola oil, soybean oil, and lard, mild for perilla, fish and palm oil, and minimal for high-carbohydrate meals. Only the mice fed the palm oil showed significant fasting hyperinsulinemia (high blood insulin levels). Body weight (or white adipose tissue [WAT] weight) and intake of LA (or n-3/n-6 ratio) were chosen as independent variables and used in multiple regression analysis to assess effects on glucose tolerance. LA intake showed a significant positive correlation with blood glucose levels but not with obesity. The authors concluded that dietary oils with differing FA profiles vary in their effects on fasting blood insulin levels. They speculated that the higher fasting blood insulin levels which resulted from the palm oil diet may explain the better glycemic control that was noted in these mice, despite their marked obesity. The investigators hypothesized that favorable glucose responses induced by ALA (in perilla oil) and fish oil feeding may be mediated and somewhat dependent upon decreases in body weight. The data suggests that obesity and higher dietary intakes of LA are independent risk factors for defective blood glucose regulation in NIDDM.
