Effects Of A Novel Whey-derived Peptide On Vascular Responses In Healthy Individuals

Abstract

PURPOSE: Whey protein is a potential source of bioactive peptides. Based on findings from in vitro experiments showing a whey derived peptide increased endothelial nitric oxide synthesis, we tested the in vivo bioactivity of the peptide on vascular function in healthy humans. METHODS: A randomized, double blind, placebo-controlled, crossover study design was used. Twenty healthy men and women (age 25 ± 5 yr, body mass 69.8 ± 9.1 kg, BMI 24.3 ± 2.3 kg/m2) participated in two vascular testing days each preceded by 2 wk of supplementation with 5 g/day of a novel whey-derived peptide (WP) or placebo. There was a 1-2 wk washout period between trials. After two weeks of supplementation, vascular function and circulating biomarkers were assessed in response to a single dose of either WP or placebo. Macrovascular and microvascular function were assessed using brachial artery flow mediated dilation (FMD) via high-resolution ultrasound and venous occlusion strain gauge plethysmography, respectively. RESULTS: Baseline peak FMD was not different for placebo (7.7%) and WP (7.8%). Placebo intake had no effect on FMD at 30, 60, and 90 min post-ingestion (7.5%, 7.2%, and 7.6%, respectively) whereas WP resulted in a significant increase compared to baseline (8.9%, 9.9%, and 9.0%, respectively) (P = 0.000 for time × trial interaction). Baseline reactive hyperemia forearm blood flow was not different for Placebo (27.2 ± 7.2 %/min) and WP (27.3 ± 7.6 %/min). Placebo intake had no effect on reactive hyperemia forearm blood flow measured 120 min post-ingestion (27.2 ± 7.8 %/min) whereas WP resulted in a significant increase compared to baseline (29.9 ± 7.8 %/min) (P = 0.008 for time × trial interaction). The insulin response was significantly higher during WP than placebo at 15, 30, and 45 min, but there were no significant differences in glucose, myeloperoxidase, total nitrites/nitrates, and inflammatory responses. CONCLUSIONS: Consistent with cellular work showing components of whey protein have nitric oxide enhancing effects, these findings indicate that supplementation with a novel whey derived peptide in healthy individuals improves vascular function, perhaps by increasing basal NO bioavailability.