Protein From Yellow Peas May Lower Blood Pressure
Finding in rats holds promise against kidney disease, too, experts say
SUNDAY, March 22, 2009 (HealthDay News) -- Certain proteins found in the yellow garden pea appear to help lower blood pressure and delay, control or even prevent the onset of chronic kidney disease, at least in rats, a Canadian study has found.
"What we seem to have here is sort of a natural approach to treating this disease, as opposed to the normal pharmacological approach," said the study's lead author, Rotimi E. Aluko, an associate professor in the department of human nutritional sciences at the University of Manitoba in Winnipeg. "We're talking about an edible product, not a drug, which can help to reduce blood pressure and, at the same time, reduce the severely negative impact of kidney disease."
Aluko and his colleagues were to present their findings Sunday at the American Chemical Society's national meeting in Salt Lake City. The study was underwritten by several Canadian government entities.
Kidney disease affects an estimated 13 percent of American adults, the authors noted, and is a notoriously difficult disease to treat, with most people eventually succumbing to cardiovascular complications from high blood pressure linked to kidney malfunction.
Because of this, the researchers focused on the potential effect on blood pressure that might come from peas, long-heralded as a cholesterol-free source of fiber and protein.
After purifying a mix of yellow garden pea proteins, collectively called "pea protein hydrolysate," the researchers spent eight weeks feeding the derivative to rats that had kidney disease.
They found that blood pressure dropped 20 percent in the rats treated with the pea protein mixture, compared with the blood pressure of untreated rats.
They also found that urine production, which can be severely curtailed by kidney function breakdown, improved by upwards of 30 percent among the treated rats.
Despite the positive findings, the researchers do not advocate the ad hoc consumption of yellow green peas. They explained that a complex protein purification process is needed to activate what is otherwise a dormant vegetable benefit.
The pea protein would need to be mixed with certain enzymes into a food additive or nutritional supplement in liquid or pill form. In that form, Aluko said, it might be easier to tolerate than blood pressure drugs, given the pea protein's natural sourcing. A natural treatment, he said, would also eliminate the risk for overdosing.
He said that human trials are underway and that, if successful, a pea-based therapy might be available in two to three years.
Dr. George Bakris, director of the hypertensive diseases unit at the University of Chicago, described the finding as "fascinating."
"This is not the first time that the secret to blood pressure control has been found in Mother Nature," Bakris noted. "Ten years ago, a substance was isolated in celery, for example, that also had a controlling effect. But here what they seem to have shown is that there is a substance in this pea, when cleaved, which works in a similar fashion to the ACE inhibitors that have been out for the last 25 years. So basically, they have a natural substance that works like standard drugs we know a lot about."
"Of course, we have to see what the human studies show, " Bakris cautioned. "But if the results are as compelling as they were in animals, then this would potentially be a very reassuring, exciting and positive development as it is certainly very difficult to control blood pressure in people with kidney disease."
The American Heart Association has more on hypertension.