Effects Of A Novel Whey-derived Peptide On Vascular Responses In Healthy Individuals
Kevin D. Ballard, Richard S. Bruno, Richard L. Seip, Erin E. Quann, Brittanie M. Volk, Daniel J. Freidenreich, Diana M. Kawiecki, William J.
Kraemer, FACSM, Jeff S. Volek. University of Connecticut, Storrs, CT. (Sponsor: William J. Kraemer, FACSM)
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
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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 x 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 x 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.
