The study, published in the Journal of the American Society of Nephrology (JASN), examined the association between dietary acidic load (DAL) and kidney disease progression to end-stage renal disease (ESRD) in a group of US-based participants.
It is believed to be the largest study to look at the long-term impact of diet on kidney disease in humans, and reports that a diet high in animal proteins - especially red meat - can worsen the progression of kidney disease.
"Our study found that patients with chronic kidney disease who consumed diets high in animal protein were three times more likely to develop kidney failure than patients who consumed diets high in fruits and vegetables," said study co-author Dr Donald Wesson from Texas A&M College of Medicine.
Study details
The findings were based on data collected from 1,486 adults with chronic kidney disease who were participating in the National Health and Nutrition Examination Survey III.
Wesson explained that when humans eat animal proteins such as red meat, the body metabolises these proteins into acids. The kidneys produce substances to help the body rid itself of this acid, but these substances can hurt kidney function if they remain at high levels in the body over long periods of time.
"It's like a double-edge sword," commented Wesson. "In the short term these substances can help the kidneys get rid of acid, but in the long-term they can reduce kidney function."
Dietary changes
Wesson’s previous research has suggested that when animals or humans switch from a diet high in animal protein to one high in plant proteins such as fruits and vegetables, kidney function is protected. This is because the body metabolizes plant proteins into bases, not acids.
Wesson currently is a co-investigator on a multi-centre, €1.8million ($2m) grant from the National Institutes of Health (NIH) to conduct a national study to confirm if reducing dietary acid slows or prevents worsening of kidney disease.
He added that while studies have yet to prove that eating a diet high in fruits and vegetables can prevent kidney disease, such diets have already been shown to help to maintain overall good health.
"We know that fruits and vegetables are 'heart friendly' and these ongoing studies will help confirm if they are also 'kidney friendly'," said Wesson.
Source: JASN
Published online ahead of print, doi: 10.1681/ASN.2014040332
"High Dietary Acid Load Predicts ESRD among Adults with CKD"
Authors: Tanushree Banerjee, et al