| Background. Whey protein is a potential source of bioactive peptides with previous evidence indicating beneficial effects of chronic whey consumption on cardiovascular risk factors. Therefore, we sought to determine the impact of ingestion of a whey-derived peptide (NOP-47) on vascular endothelial function in humans.;Methods. A randomized, placebo-controlled, crossover study design was used. Healthy, young (n =20) (25 +/- 5 y, BMI = 24.3 +/- 2.3 kg/m2) (Study I) 17 and older men and women (n = 21) (55 +/- 6 y, BMI = 27.8 +/- 2.9 kg/m2 ) (Study II) participated in two acute testing days, one preceded by supplementation with NOP-47 or placebo for two weeks and the other a screening visit to verify impaired brachial artery flow mediated dilation (FMD), respectively. Peripheral endothelial function and circulating endothelial-related biomarkers were measured serially for 2 h after ingestion of 5g NOP-47 or placebo.;Results. In young individuals (Study I), 2 wk of supplementation had no effect on fasting measures of endothelial function, but acute NOP-47 ingestion improved FMD compared to baseline (7.8%) at 30, 60 and 90 min (8.9%, 9.9%, and 9.0%; P<0.0001 for timextrial interaction) and peak reactive hyperemia forearm blood flow measured at 120 min post-ingestion (P=0.008 for timextrial interaction). Plasma nitric oxide metabolites (NOx) were lower at 120 min after placebo compared to NOP-47 (P<0.05). Similarly, in older, overweight individuals with impaired FMD at baseline (3.7%) (Study II), acute NOP-47 ingestion increased FMD at 30 (4.6%) and 120 min (5.1%) post-ingestion (P<0.05 for timextrial interaction). The 120 min FMD value was higher following NOP-47 ingestion compared to placebo (4.3%) (P<0.05). A significant inverse relation was detected between pre-occlusion diameter and %FMD in the peptide trial only. When concentrations were calculated as the change from pre-ingestion values, no main effects were detected for NOx or the prostacyclin metabolite, 6-keto-PGF1alpha.;Conclusion. Acute ingestion of a peptide derived from whey protein improved endothelium-dependent dilation in young and middle-aged men and women. Future investigation of this peptide in a clinical population or as a functional food ingredient to attenuate the vascular disturbances associated with a postprandial meal challenge is warranted. |
