Newton-Tanzer Emily, Can Sultan Nilay, Demmelmair Hans, Horak Jeannie, Holdt Lesca, Koletzko Berthold, Grote Veit
Division of Metabolic and Nutritional Medicine, Department Paediatrics, Dr. von Hauner Children's Hospital, LMU University Hospital, LMU Munich, and the German Center for Child and Adolescent Health, site Munich, 80337 Munich, Germany.
Institute of Laboratory Medicine, LMU University Hospital, LMU Munich, 80337 Munich, Germany.
J Clin Endocrinol Metab. 2025 May 19;110(6):e1793-e1801. doi: 10.1210/clinem/dgae599.
Milk protein contains high concentrations of branched-chain amino acids (BCAA) that play a critical role in anabolism and are implicated in the onset of obesity and chronic disease. Characterizing BCAA catabolism in the postprandial phase could elucidate the impact of protein intake on obesity risk established in the "early protein hypothesis."
To examine the acute effects of protein content of young child formulas as test meals on BCAA catabolism, observing postprandial plasma concentrations of BCAA in relation to their degradation products.
The TOMI Add-On Study is a randomized, double-blind crossover study in which 27 healthy adults consumed 2 isocaloric young child formulas with alternating higher (HP) and lower (LP) protein and fat content as test meals during separate interventions, while 9 blood samples were obtained over 5 hours. BCAA, branched-chain α-keto acids (BCKA), and acylcarnitines were analyzed using a fully targeted HPLC-ESI-MS/MS approach.
Mean concentrations of BCAA, BCKA, and acylcarnitines were significantly higher after HP than LP over the 5 postprandial hours, except for the BCKA α-ketoisovalerate (KIVA). The latter metabolite showed higher postprandial concentrations after LP. With increasing mean concentrations of BCAA, concentrations of corresponding BCKA, acylcarnitines, and urea increased until a breakpoint was reached, after which concentrations of degradation products decreased (for all metabolites except valine and KIVA and Carn C4:0-iso).
BCAA catabolism is markedly influenced by protein content of the test meal. We present novel evidence for the apparent saturation of the BCAA degradation pathway in the acute postprandial phase up to 5 hours after consumption.
乳蛋白含有高浓度的支链氨基酸（BCAA），这些氨基酸在合成代谢中起关键作用，并与肥胖和慢性疾病的发生有关。表征餐后阶段的BCAA分解代谢可以阐明蛋白质摄入对“早期蛋白质假说”中确定的肥胖风险的影响。
研究幼儿配方奶粉蛋白质含量作为测试餐对BCAA分解代谢的急性影响，观察餐后血浆BCAA浓度与其降解产物的关系。
TOMI附加研究是一项随机、双盲交叉研究，27名健康成年人在单独的干预期间食用两种等热量的幼儿配方奶粉，分别作为高蛋白（HP）和低蛋白（LP）、高脂肪含量的测试餐，同时在5小时内采集9份血样。使用全靶向HPLC-ESI-MS/MS方法分析BCAA、支链α-酮酸（BCKA）和酰基肉碱。
在餐后5小时内，除了BCKAα-酮异戊酸（KIVA）外，HP后的BCAA、BCKA和酰基肉碱的平均浓度显著高于LP。后一种代谢物在LP后显示出更高的餐后浓度。随着BCAA平均浓度的增加，相应的BCKA、酰基肉碱和尿素的浓度增加，直到达到一个转折点，此后降解产物的浓度降低（除缬氨酸、KIVA和肉碱C4:0-异体外的所有代谢物）。
BCAA分解代谢受测试餐蛋白质含量的显著影响。我们提供了新的证据，证明在进食后长达5小时的急性餐后阶段，BCAA降解途径明显饱和。
