Study shows peptide in whey protein helps reduce arterial stiffness.

A whey-derived bioactive peptide promotes more blood vessel relaxation, a new study finds.

Researchers from the University of Connecticut found that a peptide extract from undenatured whey protein improved endothelial function in middle-aged adults, thus reduced the burden of blood flow on the heart.

Measuring flow-mediated dilation (FMD), an indicator of arterial stiffness, the authors reveal that a whey protein extract successfully reminds arteries to relax. Noting that previous studies have found that dairy proteins support healthy blood pressure, this is the first research documenting a direct benefit of whey protein on endothelial function in an elderly, at risk, population.

Researchers dosed 21 men and women between the ages of 45 and 65 with a 5 gram supplement of whey protein extract or a placebo. Amino acid concentrations, FMD, insulin, and compounds known to act on the blood vessels were measured for 2 hours after ingestion.

The authors reported an increase in vasodilation (vessel relaxation) by 1 to 1.5 percent. Although a small number, the researchers emphasize that this change packs a big punch. A stiffer artery accompanies a low FMD. Boosting arterial elasticity by just 1 percentage point, the researchers explain, cuts potential perils to the heart by a factor of 12.

“The findings of the present study indicate that acute ingestion of an extract derived from whey protein was rapidly absorbed and improved endothelium-dependent dilation in older adults with vascular endothelial dysfunction,” the authors report.

Whey’s benefit on blood pressure, the authors suggest, may be explained by this relaxation of the vessels, allowing for easier circulation throughout the body. According to these findings, the rapidly absorbed amino acids found in whey protein promote vasodilation—a likely explanation for the decreases in blood pressure reported in other studies.

The jury is still out on how the composition of whey protein, and this whey protein extract, enables arterial release. For example, two important factors in vascular health are nitric oxide—a potent vasodilator—and angiotensin converting enzyme (ACE), an important enzyme in blood pressure regulation. Interestingly, however, the whey protein supplement failed to effect levels of either nitric oxide or ACE, suggesting other likely ways may be responsible for whey’s benefits on circulation.

The researchers used a bioactive tri-peptide—a short protein chain consisting of three amino acids—derived from whey. Maintaining the integrity of this protein chain, from milk, in processing, and through the gut, may be the key to explaining how this extract boosts endothelial function.

Amino acids are used to build body proteins; peptides, on the other hand, are used to communicate, interact with, and direct the functional responses of cells. Undenatured whey protein undergoes less processing and is more likely to retain these bioactive peptides—preserving the small protein during absorption is the tough part.

This research suggests that the hearty benefits of this tripeptide may come from the nature of the structure, not just the amino acids that it is composed of. Further investigation, the authors write, is required to confirm that this peptide retains its structure during absorption and goes on to act as a signaling molecule in the body. In this case, the tripeptide’s signal is acting on the arterial walls.

Tight blood vessels counteract cardiac health, an effect common in aging. With room for more research, the authors write that older individuals experiencing impaired endothelial function could release some strain in the arteries by eating these bioactive peptides sourced from whey protein.


Ballard KD et al. Acute effects of ingestion of a novel whey-derived extract on vascular endothelial function in overweight, middle-aged men and women. British Journal of Nutrition 2012.