Fractional oxidation of chylomicron-derived oleate is greater than that of palmitate in healthy adults fed frequent small meals1

Abstract

Differences in oxidation of individual dietary fatty acids could contribute to the effect of dietary fat composition on risk factors for non-insulin-dependent diabetes mellitus and cardiovascular disease. Using a novel stable isotope technique, we compared fractional oxidation of chylomicron-derived oleate and palmitate in 10 healthy adults in a crossover study. 1-13C-labeled oleate or palmitate was emulsified into a eucaloric formula diet administered each 20 min for 7 h to produce a plateau in excretion of 13C label in breath CO2. Unlabeled oleate and palmitate each provided 16% of dietary energy, and other fatty acids provided 8% of energy. Total dietary fat was 40% of energy, carbohydrate was 46%, and protein was 14%. Diet without tracer was fed for 2 h before beginning tracer administration to establish a baseline fed state. Relative oxidation of oleate versus palmitate was defined as fractional oxidation of oleate divided by fractional oxidation of palmitate. Relative oxidation averaged 1.21 (99.5% confidence interval = 1.03–1.39), indicating that fractional oxidation of oleate was significantly greater than that of palmitate.—Schmidt, D. E., J. B. Allred, and C. L. Kien. Fractional oxidation of chylomicron-derived oleate is greater than that of palmitate in healthy adults fed frequent small meals.

Keywords

• dietary fat
• chylomicrons
• fatty acid oxidation
• stable isotopes