Work

Milk Protein Glycation Compromises Postprandial Lysine Bioavailability but does not Modulate Postprandial Muscle Protein Synthesis Rates In Vivo in Males: A Double-blind, Randomized Parallel Trial

Year: 2025

Type: article

Study designs: Randomized Controlled Trial, Clinical Trial

Abstract: Background Industrial processing and storage of milk products can strongly increase protein glycation level. Previously, we have reported that a high protein glycation level impairs protein digestion, thereby compromising lysine bioavailability. The lower post-prandial lysine availability may restrict the anabolic properties of a high glycated protein. Objective To assess the impact of milk protein glycation on post-prandial plasma amino acid availability and subsequent post-prandial muscle protein synthesis rates during recovery from a single bout of resistance-type exercise. Methods 45 recreationally active, healthy young males participated in this double-blinded, randomized parallel study. After performing a single bout of whole-body resistance-type exercise, subjects ingested 20 g milk protein with either a low (4%; LOW-GLYC) or high (47%; HIGH-GLYC) glycation level, or a non-caloric placebo (PLA). Continuous intravenous infusion of L-[ ring - 13 C 6 ]-phenylalanine was combined with the collection of blood and muscle tissue samples during a 6-h post-prandial period to assess plasma amino acid concentrations and muscle protein synthesis rates. Results Protein ingestion increased plasma total and essential amino acid concentrations compared to placebo (time*treatment interaction: P<0.001), with no differences between the low and high glycated milk protein. Plasma lysine availability, assessed over the full 6 h post-prandial period, was substantially lower following ingestion of the protein with the high versus low glycation level (-5±7 vs 10±9 mmol·L-1·360 min, respectively, P<0.001). Post-prandial muscle protein synthesis rates did not differ between treatments (0.059±0.016, 0.061±0.012, and 0.061±0.018 %·h-1, in LOW-GLYC, HIGH-GLYC and PLA, respectively, P=0.939). Conclusion Ingestion of protein with a higher glycation level attenuates post-prandial plasma lysine availability. Milk protein glycation does not modulate post-prandial muscle protein synthesis rates during recovery from resistance exercise in healthy, young males. This trial was registered at the Dutch Trial Register as NL8690; https://onderzoekmetmensen.nl/nl/trial/49398 .

Source: Journal of Nutrition

DOI: 10.1016/j.tjnut.2025.05.032