ARS | Publication request: A low fat diet enhances polyunsaturated fatty acid desaturation and elongation independent of n3 enrichment

Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 11, 2010
Publication Date: March 17, 2011
Citation: Raatz, S.K., Orr, L.R., Kurzer, M.S., Picklo, M.J. 2011. A low fat diet enhances polyunsaturated fatty acid desaturation and elongation independent of n3 enrichment. Federation of American Societies for Experimental Biology Conference. 25:338.2.

Technical Abstract: Low fat diets are associated with risk reduction for chronic metabolic diseases compared to high fat diets. To evaluate effects of varied fat and fatty acid intake on lipid metabolism, phospholipid fatty acids (PLFA) were measured and delta 5 and 6 desaturase activities (D5D, D6D) were calculated in a cross-over trial in 17 postmenopausal women fed test diets for 8-week feeding periods (40% fat (HF), 20% fat (LF) and a low fat diet +n3 (23% fat; LFn3). Desaturase activity was calculated as D5D: 20:4n6/20:3n6 and D6D: 20:3n6/18:2n6. PLFA 18:3n3, 20:5n3, 22:6n3 and total n3 increased and 18:2n6, 20:4n6 reduced with LFn3 (all p < 0.0001). LF resulted in enhanced 20:4n6 and 22:6n3 (p=.02, p=.05, respectively). HF reduced D6D (p=.001) while both HF and LF increased D5D (p=.04, p=.05, respectively). In comparison to the HF, LF promoted production of ARA and DHA while LFn3 diet promoted direct incorporation of ALA, EPA, DPA and DHA into PLFA and suppressed LA and ARA. The observed effects on lipid metabolism in response to LF and LFn3 may explain the associated risk reduction for chronic metabolic disease with low fat diets.