Reduced oxidation of dietary fat after a short term high-carbohydrate diet

R. Roberts, A.S. Bickerton, B.A. Fielding, E.E. Blaak, A.J. Wagenmakers, M.F. Chong, M. Gilbert, F. Karpe, K.N. Frayn

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    Abstract

    BACKGROUND: Short-term high-carbohydrate (HC) diets induce metabolic alterations, including hypertriacylglycerolemia, in both the fasting and postprandial states. The underlying tissue-specific alterations in fatty acid metabolism are not well understood. OBJECTIVE: We investigated alterations in exogenous and endogenous fatty acid metabolism by using stable isotope tracers to label meal triacylglycerol and plasma fatty acids. DESIGN: Eight healthy subjects consumed isocaloric diets containing a high percentage of energy from carbohydrates or a higher percentage of energy from fat for 3 d in a randomized crossover dietary intervention study. A test meal containing [U-13C] palmitate was combined with intravenous infusion of [2H2] palmitate to label plasma fatty acids and VLDL triacylglycerol. Blood and breath samples were taken before the meal and for 6 h postprandially. Blood samples were drawn from the femoral artery and from veins draining subcutaneous adipose tissue and forearm muscle for monitoring of tissue-specific metabolic substrate partitioning. RESULTS: Systemic triacylglycerol concentrations were increased in both fasting (P = 0.02) and postprandial (P = 0.02) periods, and a greater amount of infused labeled fatty acid appeared in VLDL triacylglycerol after the HC diet than after the higher-fat diet (P = 0.05). Significantly less 13CO2 was exhaled after the HC diet (P = 0.04) and significantly less production of 13CO2 was seen across forearm muscle (P = 0.04). Systemic 3-hydroxybutyrate was significantly lower, postprandially, after the HC diet (P = 0.02). CONCLUSION: Metabolic alterations suggestive of repartitioning of fatty acids away from oxidation toward esterification in both liver and muscle occur in response to short-term adaptation to a HC diet.
    Original languageEnglish
    Pages (from-to)824-31
    JournalAmerican Journal of Clinical Nutrition
    Volume87
    Issue number4
    DOIs
    Publication statusPublished - 1 Jan 2008

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