Consumption of Whey in Combination with Dairy Medium-Chain Fatty Acids (MCFAs) may Reduce Lipid Storage due to Urinary Loss of Tricarboxylic Acid Cycle Intermediates and Increased Rates of MCFAs Oxidation

cope We aimed to investigate whether changes in the metabolome could explain observed changes in body composition in overweight adults after consumption of butter with high level of medium-chain fatty acids (MCFAs) in combination with casein or whey. Methods and results With GC-ToF and LC-Q/MS, we analyzed metabolites in plasma and urine from a 12-weeks randomized double-blinded human intervention including 52-abdominally overweight adults. The participants consumed 63 g/day of milk fat (high or low in MCFAs) and 60 g/day of protein (whey or casein). Urinary loss of the tricarboxylic acid cycle metabolites and a concomitantly increase of glycerol in blood were observed in the whey + high-MCFAs group, indicating potential lower anabolic processes, such as lipogenesis, by draining substrates. High intake of MCFAs resulted in elevated level of urinary adipic (independently of protein type) and plasma sebacic acid (with whey), indicating a potential increase in oxidation of MCFAs, which might lead to energy loss. Conclusion The type of protein showed highest effect on the overall metabolic profiles, but ω-oxidation of MCFAs in the liver seemed to be the main reason for the observed reduction in body fat mass after consumption of high MCFAs, independent of type of protein. This article is protected by copyright. All rights reserved