Dietary saturated fatty acid type impacts obesity-induced metabolic dysfunction and plasma lipidomic signatures in mice

Authors: ZACEK, PETR - Former ARS Employee; Bukowski, Michael; Mehus, Aaron; JOHNSON, LUANN - University Of North Dakota; Zeng, Huawei; Raatz, Susan; Idso, Joseph; Picklo, Matthew

Submitted to: Journal of Nutritional Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2019
Publication Date: 10/21/2018
Publication URL: https://handle.nal.usda.gov/10113/6197112
Citation: Zacek, P., Bukowski, M.R., Mehus, A.A., Johnson, L., Zeng, H., Raatz, S.K., Idso, J.P., Picklo, M.J. 2018. Dietary saturated fatty acid type impacts obesity-induced metabolic dysfunction and plasma lipidomic signatures in mice. Journal of Nutritional Biochemistry. https://doi.org/10.1016/j.jnutbio.2018.10.005.
DOI: https://doi.org/10.1016/j.jnutbio.2018.10.005

Interpretive Summary: Saturated fatty acid (SFA) intake is associated with obesity, insulin resistance, and liver dysfunction, but scant work examines the impact of different dietary types of SFA upon these outcomes. We tested the hypothesis that an obesogenic diet prepared with medium chain saturated fats derived from coconut oil reduces obesity-induced outcomes compared to obesogenic diets prepared with increasing amounts long chain SFA derived from palm oil. Our studies, performed in mice, show that eating SFA from coconut oil reduced, but did not prevent, insulin resistance and fatty liver. We show that different types of SFA produce different characteristic lipid signatures in the blood that may be useful as biomarkers.

Technical Abstract: Saturated fatty acid (SFA) intake is associated with obesity, insulin resistance, and hepatic steatosis, but scant work examines the impact of SFA type upon these outcomes. We tested the hypothesis that an obesogenic diet prepared with medium chain SFA (MCSFA), mostly as lauric acid-derived from coconut oil, reduces obesity-induced outcomes compared to obesogenic diets prepared with increasing amounts long chain SFA (LCSFA), primarily palmitic acid. Mice were fed (16 weeks) a control, low fat diet or obesogenic diets prepared with differing content of MCSFA or LCSFA in which polyunsaturated and monounsaturated fatty acids (PUFA; MUFA) were kept constant. Inclusion of MCSFA in an obesogenic diet prevented hepatic lipid accumulation and lowered indices of insulin resistance. All obesogenic diets similarly reduced hepatic levels of the de novo lipogenesis proteins SCD1 and FASN but elevated the adipose levels of mRNA for the pro-inflammatory markers Mcp-1 and Tnfa. Lipidomic analysis of plasma indicated that MCSFA intake resulted in a different lipidomic signature than LCSFA intake, prevented elevation of pro-inflammatory ceramides, but elevated the concentrations of some lipids associated with elevated cardiovascular disease risk. Intake of the obesogenic diets in an SFA-type dependent manner elevated plasma concentrations of several phosphatidylcholine (PC) lipids having the long chain PUFA (LCPUFA) arachidonic acid (ARA) and docosahexaenoic acid (DHA), altered phospholipid ethers, as well as changed the triacylglyceryl environments of these LCPUFA. Our data indicate that in mice (1) MCSFA reduce the severity of some obesogenic co-morbidities, (2) SFA-type modulates lipidomic signatures associated with cardiovascular disease and diabetes, and (3) dietary SFA type impacts LCPUFA metabolism.