Influence of Dietary Fatty Acid Content and Composition on Lipid Metabolism in the Syrian Hamsters

Abstract

IntroductionDiets rich in n3 FAs can reduce health risks associated with obesity. Currently, US Dietary Guidelines recommend consumption of a balance of SFA:MUFA:PUFA in a 1:1:1 ratio, with a PUFA n6:n3 ratio of 3:1. However, typical Western diets have an n6:n3 ratio of ~20:1. This study evaluates the response of hepatic and adipose lipid metabolism to a dietary shift in the n6:n3 ratio from 20:1 to 3:1, using either an 18:3n3 or 20:5n3/22:6n3 rich source of n3 FAs, while maintaining the recommended lipid balance.MethodsMale hamsters were raised for 12 weeks on either 12% (LF) or 40% (HF) caloric fat with a 1:1:1 SFA/MUFA/PUFA. Initial diets (0–6wks) contained 20:1 n6:n3. At 6wk, the high fat (HF) cohort was divided into 3 groups, one maintained on the initial diet, and two switched to 3:1 n6:n3 diets derived by blending dietary corn oil with either flax (HF‐fish) or fish (HF‐flax) oil. Subjects from each regimen were sacrificed at 3wk intervals. Oral glucose tolerance was assessed in each animal 1 wk prior to cull.ResultsHF diets increased body weight ~10%, but did not alter adiposity or glucose tolerance. The composition, but not content, of plasma lipids were altered by the dietary lipid regimen, with LF diets being enriched in MUFAs, and HF diets showing elevated PUFAs, reflecting the n3 lipid content of the diet.ConclusionA low fat diet enhanced hepatic lipogenesis, while the n6/n3 fatty acid balance impacts dietary lipid profiles and contributes to overall energy balance in hamsters. This project was funded by USDA CRIS 5306‐51530‐016‐00D.Grant Funding Source: USDA CRIS 5306‐51530‐016‐00D.