Luiking Yvette C, Abrahamse Evan, Ludwig Thomas, Boirie Yves, Verlaan Sjors
Nutricia Research, Utrecht, The Netherlands; Center for Translational Research in Aging & Longevity, Dept of Health and Kinesiology, Texas A&M University, College Station, TX, USA.
Nutricia Research, Utrecht, The Netherlands.
Clin Nutr. 2016 Feb;35(1):48-58. doi: 10.1016/j.clnu.2015.02.013. Epub 2015 Mar 5.
BACKGROUND & AIMS: The requirement of leucine and essential amino acids (EAA) to stimulate muscle protein synthesis increases with age. To target muscle anabolism it is suggested that higher postprandial blood levels of leucine and EAA are needed in older people. The aim was to evaluate the impact of oral nutritional supplements with distinct protein source and energy density, resembling mixed meals, on serum amino acid profiles and on gastrointestinal behaviour.
Four iso-nitrogenous protein (21 g) supplements were studied containing leucine-enriched whey protein with 150/320 kcal (W150/W320) or casein protein with 150/320 kcal (C150/C320); all products contained carbohydrates (10 or 32 g) and fat (3 or 12 g). Postprandial serum AA profiles were evaluated in twelve healthy, older subjects who participated in a randomized, controlled, single blind, cross-over study. Gastrointestinal behaviour was studied in vitro by looking at gastric coagulation and cumulative intestinal protein digestion over time.
The peak serum leucine concentration was twofold higher for W150 vs. C150 (521 ± 15 vs. 260 ± 15 μmol/L, p < 0.001), higher for W320 vs. C320 (406 ± 15 vs. 228 ± 15 μmol/L, p < 0.001), and higher for low-caloric vs. high-caloric products (p < 0.001 for pooled analyses; p < 0.001 for interaction protein source*caloric density). Similar effects were observed for the peak concentrations of EAA and total AA (TAA). In vitro gastric coagulation was observed only for the casein protein supplements. Intestinal digestion for 90 min resulted in higher levels of free TAA, EAA, and leucine for W150 vs. C150, for W150 vs. W320, and for C150 vs. C320 (p < 0.0125).
A low caloric leucine-enriched whey protein nutritional supplement provides a higher rise in serum levels of TAA, EAA and leucine compared to casein protein or high caloric products in healthy, elderly subjects. These differences appear to be mediated in part by the gastrointestinal behaviour of these products.
ClinicalTrials.gov: NCT02013466.
随着年龄增长，刺激肌肉蛋白质合成所需的亮氨酸和必需氨基酸（EAA）量会增加。为了促进肌肉合成代谢，建议老年人餐后血液中亮氨酸和EAA水平更高。本研究旨在评估具有不同蛋白质来源和能量密度、类似混合餐的口服营养补充剂对血清氨基酸谱和胃肠道行为的影响。
研究了四种等氮蛋白质（21克）补充剂，分别为含150/320千卡亮氨酸强化乳清蛋白（W150/W320）或150/320千卡酪蛋白（C150/C320）；所有产品均含有碳水化合物（10或32克）和脂肪（3或12克）。在12名健康老年受试者中评估餐后血清氨基酸谱，这些受试者参与了一项随机、对照、单盲、交叉研究。通过观察胃凝固情况以及随时间累积的肠道蛋白质消化情况，在体外研究胃肠道行为。
W150组的血清亮氨酸峰值浓度是C150组的两倍（521±15对260±15μmol/L，p<0.001），W320组高于C320组（406±15对228±15μmol/L，p<0.001），低热量产品高于高热量产品（合并分析p<0.001；蛋白质来源*热量密度交互作用p<0.001）。EAA和总氨基酸（TAA）的峰值浓度也观察到类似效果。仅在酪蛋白补充剂中观察到体外胃凝固现象。90分钟的肠道消化后，W150组与C150组相比、W150组与W320组相比、C150组与C320组相比，游离TAA、EAA和亮氨酸水平更高（p<0.0125）。
与酪蛋白或高热量产品相比，低热量亮氨酸强化乳清蛋白营养补充剂能使健康老年受试者的血清TAA、EAA和亮氨酸水平升高幅度更大。这些差异似乎部分由这些产品的胃肠道行为介导。
ClinicalTrials.gov：NCT02013466。
