title: A High-Fat, High-Oleic Diet, But Not a High-Fat, Saturated Diet, Reduces Hepatic α-Linolenic Acid and Eicosapentaenoic Acid Content in Mice.
abstract: Considerable research has focused upon the role of linoleic acid (LNA; 18:2n-6) as a competitive inhibitor of α-linolenic (ALA; 18:3n-3) metabolism; however, little data exist as to the impact of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) on ALA metabolism. We tested the hypothesis that a high SFA diet, compared to a high MUFA (oleic acid 18:1n-9) diet, reduces ALA conversion to long chain n-3 fatty acids. Mice were fed for 12 weeks on three diets: (1) a control, 16 % fat energy diet consisting of similar levels of SFA and MUFA (2) a 50 % fat energy high MUFA energy diet (35 % MUFA and 7 % SFA) or (3) a 50 % fat energy, high SFA energy diet (34 % SFA, 8 % MUFA). ALA and LNA content remained constant. Analysis of hepatic lipids demonstrated a selective reduction (40 %) in ALA but not LNA and a 35 % reduction in eicosapentaenoic acid (EPA; 20:5n-3) in the high MUFA mice compared to the other groups. Lower content of ALA was reflected in the neutral lipid fraction, while smaller levels of phospholipid esterified EPA and docosapentaenoic acid (DPA; 22:5n-3) were evident. Docosahexaenoic acid (DHA; 22:6n-3) content was elevated by the high SFA diet. Expression of Fads1 (Δ5 desaturase) and Fads2 (Δ6 desaturase) was elevated by the high MUFA and reduced by the high SFA diet. These data indicate that a high MUFA diet, but not a high SFA diet, reduces ALA metabolism and point to selective hepatic disposition of ALA versus LNA.
authors.affiliation: USDA-ARS Grand Forks Human Nutrition Research Center, 2420 2nd Avenue North, Grand Forks, ND, 58203-9034, USA. matthew.picklo@ars.usda.gov.|Department of Chemistry, University of North Dakota, Grand Forks, ND, 58201, USA. matthew.picklo@ars.usda.gov.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Picklo
authors.affiliation: Department of Basic Sciences, University of North Dakota School of Medicine, Grand Forks, ND, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Murphy
mesh_terms: D000818:Animals; D000090943:Delta-5 Fatty Acid Desaturase; D059305:Diet, High-Fat / Q000009:adverse effects; D004281:Docosahexaenoic Acids / Q000378:metabolism; D015118:Eicosapentaenoic Acid / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000209:etiology / Q000378:metabolism; D009829:Oleic Acids / Q000378:metabolism*; D017962:alpha-Linolenic Acid / Q000378:metabolism*
chemical_list: D000090943:Delta-5 Fatty Acid Desaturase; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; D009829:Oleic Acids; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid; C000716847:FADS1 protein, human; C026219:docosapentaenoic acid
keywords: Liver; Monounsaturated fatty acid; Obesity; Polyunsaturated fatty acids; α-Linolenic acid