The combination of isoleucyl-prolyl-proline (IPP) and valyl-prolyl-proline (VPP) were found to reduce arterial stiffness and enhancing the function of the cells lining blood vessels (endothelial cells) in people with hypertension, according to results published in the European Journal of Clinical Nutrition.
About one billion people worldwide suffer from high blood pressure (hypertension), defined as having a systolic and diastolic blood pressure (BP) greater than 140 and 90 mmHg. It is a major risk factor for cardiovascular disease (CVD) - a disease that causes almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.
The results fit with wider heart health benefits of the ingredients. A meta-analysis from Chinese scientists and published in Nutrition pooled data from the trials showed that the milk tripeptides were associated with a 4.8 mmHg reduction in systolic blood pressure and a 2.2 mmHg reduction in diastolic blood pressure.
Researchers from Valio and the Univeristy of Helsinki recruited 89 people with hypertension and randomly assigned them to receive a low dose of tripeptides (5 mg/day) for 12 weeks, followed by a high dose (50 mg/day) for a further 12 weeks, or placebo.
At the end of the study, arterial stiffness, measured as augmentation index (AIx), decreased in the peptide group by 1.53 per cent, while it increased in the placebo group, report the researchers.
On the other hand, no changes in endothelial function were observed between the groups.
The researchers note that the action of the peptides may be linked to the angiotensin converting enzyme (ACE)-inhibitory activity. ACE inhibitors work by inhibiting the conversion of angiotensin I to the potent vasoconstrictor, angiotensin II, thereby improving blood flow and blood pressure.
“Another mechanism that must be considered is the fact that the functional stiffness of the large arteries is affected by the distensive effect that blood pressure exerts on the arterial walls,” they wrote.
“Given that both systolic and diastolic blood pressure diminished in the intervention group, AIx reduction could to some extent be explained by lowered blood pressure. In any case, regardless of the underlying mechanism, reduced arterial stiffness is beneficial to cardiovascular health by reducing cardiac after load and central systolic augmentation.”
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1038/ejcn.2010.3
“Long-term intervention with Lactobacillus helveticus fermented milk reduces augmentation index in hypertensive subjects”
Authors: T Jauhiainen, M Rönnback, H Vapaatalo, K Wuolle, H Kautiainen, P-H Groop and R Korpela
Full text available here.