New research from Canada found that proteins in the common garden pea may provide a natural remedy against high blood pressure and chronic kidney disease (CKD). The pea protein could be used as a natural food product such as an additive or dietary supplement to help the millions of people worldwide that suffer from these conditions, suggested the researchers.

Dr Rotimi Aluko, a food chemist at the University of Manitoba in Winnipeg, Canada will be presenting the findings at the American Chemical Society's 237th National Meeting which is taking place this week (22 - 26 March) in Salt Lake City, Utah, USA.

Hypertension or high blood pressure is a major risk factor for people with chronic kidney disease (CKD). Estimates suggests that the number of people with CKD is on the rise in the US and other countries. 13 per cent of adults in the US, about 26 million people, have CKD. This compares with 10 per cent, or 20 million in the 1990s.

CKD is difficult to treat, and many patients progress to end-stage kidney disease and have to have dialysis or a kidney transplant. Scientists are continually looking for new ways to treat CKD and stop kidneys from deteriorating.

Peas have long held prime position as "nutrition superstars" said an American Chemical Society press statement. They contain a healthy amount of protein, fiber, and vitamins and come in a "low-fat, cholesterol-free package".

The yellow garden pea is a variety used in many parts of the world and also popular with vegetarians. For instance it makes a great basis for a soup and eastern dishes like dal, where the peas are cooked to a thick puree and flavoured with spices.

Aluko told the press that:

"In people with high blood pressure, our protein could potentially delay or prevent the onset of kidney damage."

It could also help people with kidney disease live longer by helping them maintain their blood pressure, he added.

For the study, Aluko worked with University of Manitoba colleague Dr Harold Aukema. They extracted pea protein hydrolysate from the yellow garden pea and fed a small dose each day to laboratory rats bred to have a severe type of kidney disease called polycystic kidney disease.

After 8 weeks the rats on the pea protein diet showed a 20 per cent drop in blood pressure compared to diseased rats that had only been fed on a normal diet.

Aluko said this was significant because:

"A majority of CKD patients actually die from cardiovascular complications that arise from the high blood pressure associated with kidney malfunction."

In both rats and humans, polycystic kidney disease severely reduces the output of urine, preventing the kidneys from being able to rid the body of toxins. In this study the rats fed on pea extract showed a 30 per cent increase in urine production, restoring it to within normal levels.

Aluko called this a "huge improvement", and said the rats showed no adverse side effects from eating the pea protein.

The researchers now hope to test the pea protein on humans with mild hypertension.

Speculating on how the pea protein achieves the effects they found, the researchers suggested it stimulates the production of COX-1 (cyclooxygenase -1), a protein that boosts kidney function, but they don't know for sure.

Aluko said eating yellow peas in their natural state won't give you the same health benefits as the pea protein they extracted in the lab, which can only be activated with special enzymes. If the human trials are successful, the researchers envisage their special protein being commercially available within the next two to three years.

The extract could be made into pill form or a into powder for adding to food and drinks, they said.