Greater proportions of plant protein in the diet are associated with a decreased death risk among individuals with chronic kidney disease (CKD), a new study found.

The study, led by Srinivasan Beddhu, MD, of the University of Utah School of Medicine in Salt Lake City, examined data from 14,866 participants in the National Health and Nutrition Examination Survey III. In a subpopulation of 1,065 patients with CKD (estimated glomerular filtration rate [eGFR] less than 60 mL/min/1.73 m2), each 33% increase in plant protein to total protein ratio was associated with a 23% decreased death risk among individuals, after adjusting for demographics, alcohol use, smoking, body mass index, and other potential confounders. In addition, compared with individuals in the lowest quartile of plant protein ratio (less than 24.4%), those in highest quartile (greater than 41.3%) had a 33% decreased death risk in adjusted analyses. The researchers observed no significant association between plant protein intake and death risk among individuals without CKD.

The researchers published their study findings online ahead of print in the American Journal of Kidney Diseases (AJKD).

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“We know that moderate restriction of total protein intake is probably important to preserve kidney function in people with CKD, however, the effect of sources of protein on overall health in CKD has not been well studied,” Dr. Beddhu, MD, said in a statement issued by the National Kidney Foundation, which publishes the AJKD. “Our research indicates that plant-based proteins could play an important role in improving the health outcomes for people with decreased kidney function.”

“Previous studies have shown that the rate of intestinal phosphorus absorption is higher from animal protein than plant-based protein.” said Thomas Manley, Director of Scientific Activities for NKF. “Higher blood phosphorus levels are associated with increased mortality in both people with CKD and the general population. This may be one plausible explanation for the higher death rates in CKD patients who consume larger amounts of animal protein.”

Dr. Beddhu’s team advised caution in interpreting the study findings. “Whether the results are related to the plant protein itself or to the higher polyunsaturated fatty acid and lower saturated fatty acid or increased fiber levels associated with more plant-based diets is difficult to establish without intervention trials that increase solely plant protein,” they wrote.