在一项双盲随机交叉试验中，与摄入酪蛋白和乳清蛋白相比，在男性分解代谢条件下，β-乳球蛋白具有胰岛素刺激作用。

β-Lactoglobulin Is Insulinotropic Compared with Casein and Whey Protein Ingestion during Catabolic Conditions in Men in a Double-Blinded Randomized Crossover Trial.

机构信息

Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark.

Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark.

出版信息

J Nutr. 2021 Jun 1;151(6):1462-1472. doi: 10.1093/jn/nxab010.

DOI:10.1093/jn/nxab010

PMID:33693737

Abstract

BACKGROUND

Muscle loss during acute infectious disease is mainly triggered by inflammation, immobilization, and malnutrition.

OBJECTIVE

The objective was to compare muscle protein kinetics and metabolism following ingestion of the dairy protein supplements β-lactoglobulin (BLG), casein (CAS), and whey (WHE) during controlled catabolic conditions.

METHODS

We used a randomized crossover design (registered at clinicaltrials.gov as NCT03319550) to investigate 9 healthy male participants [age: 20-40 y; BMI (in kg/m2) 20-30] who were randomly assigned servings of BLG, CAS, or WHE (0.6 g protein/kg, one-third as bolus and two-thirds as sip every 20 min) on 3 separate occasions separated by ∼6-8 wk. The participants received an infusion of lipopolysaccharide (1 ng/kg) combined with 36 h of fasting and bed rest before each study day, mimicking a clinical catabolic condition. The forearm model and isotopic tracer techniques were used to quantify muscle protein kinetics. Muscle biopsy specimens were obtained and intramyocellular signaling investigated using Western blot.

RESULTS

BLG, CAS, and WHE improved the net balance of phenylalanine (NBphe) from baseline with ∼75% (P < 0.001) with no difference between interventions (primary outcome, P < 0.05). No difference in rates of appearance and disappearance of phenylalanine or in intramyocellular signaling activation was found between interventions (secondary outcomes). The incremental AUC for serum insulin was 62% higher following BLG compared with CAS (P < 0.001) and 30% higher compared with WHE (P = 0.002), as well as 25% higher in WHE compared with CAS (P = 0.006). Following BLG consumption, plasma concentrations of glucose-dependent insulinotropic peptide (GIP) increased 70% compared with CAS (P = 0.001) and increased 34% compared with WHE (P = 0.06). No significant difference was found between WHE and CAS (P = 0.12).

CONCLUSION

BLG, WHE, and CAS have similar effects on muscle in young male participants during catabolic conditions. BLG showed specific, possibly GIP-dependent, insulinotropic properties, which may have future clinical implications.

摘要

背景

急性传染病期间的肌肉损失主要是由炎症、固定和营养不良引发的。

目的

本研究旨在比较在受控分解代谢条件下摄入乳蛋白补充剂β-乳球蛋白（BLG）、酪蛋白（CAS）和乳清（WHE）后肌肉蛋白动力学和代谢的变化。

方法

我们采用随机交叉设计（在 clinicaltrials.gov 上注册为 NCT03319550），对 9 名健康男性参与者[年龄：20-40 岁；BMI（kg/m2）20-30]进行了研究，他们被随机分配在 3 个不同的时间点摄入 BLG、CAS 或 WHE（0.6 g 蛋白/kg，三分之一作为推注，三分之二作为每 20 分钟一口）。在每次研究日之前，参与者接受脂多糖（1ng/kg）输注，并进行 36 小时的禁食和卧床休息，模拟临床分解代谢状态。使用前臂模型和同位素示踪技术来定量肌肉蛋白动力学。采集肌肉活检标本，使用 Western blot 技术研究细胞内信号转导。

结果

BLG、CAS 和 WHE 均能改善苯丙氨酸的净平衡（NBphe），与基线相比提高了约 75%（P<0.001），但各干预措施之间无差异（主要结局，P<0.05）。各干预措施之间，苯丙氨酸的出现和消失率以及细胞内信号转导的激活率均无差异（次要结局）。与 CAS 相比，BLG 使血清胰岛素的增量 AUC 增加了 62%（P<0.001），与 WHE 相比增加了 30%（P=0.002），与 CAS 相比，WHE 使血清胰岛素的增量 AUC 增加了 25%（P=0.006）。BLG 摄入后，与 CAS 相比，血浆葡萄糖依赖性胰岛素释放肽（GIP）的浓度增加了 70%（P=0.001），与 WHE 相比增加了 34%（P=0.06）。WHE 与 CAS 之间无显著差异（P=0.12）。