17/11/2006 - A daily supplement of hydrolysed whey protein successfully lowered blood pressure in hypertensive people, says a new study that backs up results from animals.
Milk proteins - both caseins and whey proteins - have previously been shown to significantly reduce blood pressure in animal models, and the new study published in the November issue of the The Journal of Clinical Hypertension (Vol. 8, pp. 775-782), reports similar results in a small group of hypertensive humans. There are an estimated 10m people in the UK with hypertension, defined as having blood pressure higher than 140/90 mmHg. The condition is a major risk factor for cardiovascular disease (CVD), which causes almost 50 per cent of deaths in Europe, and is reported to cost the EU economy an estimated €169bn ($202bn) per year.The new study, by Joel Pins and Joseph Keenan from the University of Minnesota, looked at the effects of a daily 20 gram supplement of hydrolysed whey protein (experimental group) or an unmodified whey protein (control group) on 30 prehypertensive or stage 1 hypertensive people, defined as having a blood pressure between 120/80 and 155/95 mm Hg.Whey contains a variety of proteins, each with unique functional and nutritional characteristics, such as beta-lactoglobulin, alpha-lactalbumin, glycomacropeptide, serum albumin, immunoglobulins, lactoferrin and lactoperoxidase. Some of these bioactive peptides are said to be an angiotension converting enzyme (ACE) inhibitory peptides.Throughout the six-week controlled study and four-week follow-up period, Pins and Keenan measured blood pressure, blood lipids, safety measures, side effects, and diet. The Minnesota researchers report that supplementation with the hydrolysed whey proteins was associated with an average systolic blood pressure decrease of 8.0 mm Hg and an average drop in diastolic blood pressure of 5.5 mm Hg, compared with the control group.They also observed an improvement of low-density lipoprotein (LDL) cholesterol and C-reactive protein (CRP) levels. “Whey-derived peptides might be a viable option for prehypertensive and/or stage 1 hypertensive populations,” concluded the researchers.
No mechanistic study was performed by the researchers, but previous links to inhibiting ACE appear probable. By inhibiting the ACE conversion of angiotensin I to the potent vasoconstrictor, angiotensin II, blood flow and subsequently blood pressure are improved.
It is clear that significant further work is required especially with larger and more diverse sample populations and with longer follow-up times.
The study does add to a growing body of research reporting a link between protein consumption, particularly from vegetable sources, and a decreased risk of hypertension.
Indeed, studies linking vegetable protein and reductions in blood pressure are becoming frequent, such as a recent article in Archives of Internal Medicine (Vol. 166, pp. 79-86) by British researchers following 4680 people in China, Japan, the US and the UK