Metabolism of dietary stearic acid relative to other fatty acids in human subjects.
This paper reviews results obtained by stable-isotope-tracer methods for stearic acid (18:0) and palmitic acid (16:0) metabolism and the influence of dietary linoleic acid on the metabolism of these saturated fatty acids in humans subjects. The results, based on stable-isotope-tracer data, show that absorption of 18:0 is not significantly different from 16:0; percent desaturation of 18:0 to 9-cis 18:1 (9.2%) is 2.4 times higher than for 16:0 to 9-cis 16:1 (3.9%) and 9-desaturation is not greatly influenced by the amount of linoleic acid in typical US diets. Additionally, compared with 16:0, 18:0 incorporation is 30-40% lower for plasma triglyceride and cholesterol ester and approximately 40% higher for phosphatidylcholine; beta-oxidation of saturated fatty acids was slower than for unsaturated fatty acids and increasing the intake of dietary linoleic acid decreased beta-oxidation of saturated fatty acids. These results indicate that metabolic differences between 18:0 and 16:0 only partially explain the difference in the cholesterolemic effect reported for these saturated fatty acids.
Emken
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USDA, ARS, NCAUR, Peoria, IL 61604.
D000042:Absorption; D000215:Acylation; D004041:Dietary Fats / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D006801:Humans; D007553:Isotope Labeling; D010084:Oxidation-Reduction; D013229:Stearic Acids / Q000378:metabolism*
D004041:Dietary Fats; D005227:Fatty Acids; D013229:Stearic Acids; C031183:stearic acid