In older individuals with chronic kidney disease (CKD), a higher intake of animal or plant protein is associated with reduced mortality. This finding comes from an analysis of three cohorts from Spain and Sweden, the results of which were published in JAMA Network Open.

In old age, our protein requirement increases. The recommended protein intake is between 1.0 and 1.2 g per kg of actual body weight per day. For elderly patients with acute and chronic illnesses, injuries, or malnutrition, the requirement may be higher.

“While older adults may need more protein than younger persons, higher protein intake could accelerate disease progression among those with CKD, a prevalent condition in older adults that often has no cure and high morbidity and mortality,” wrote Dr Adrián Carballo-Casla of the Aging Research Center at the Karolinska Institutet in Stockholm, Sweden, and his colleagues.

Protein Restriction

The current Kidney Disease: Improving Global Outcomes guideline recommends that patients with mild CKD (ie, stages 1 and 2) not consume more than 1.3 g/kg/day of protein. In stages 3-5 (without dialysis) of CKD, protein intake should be limited to 0.6-0.8 g/kg/day. “Such a regimen of lower protein intake has been shown to slow CKD progression rates and improve metabolic derangements in persons with CKD stages 4 and 5 not receiving dialysis,” the researchers wrote. “Insufficient evidence of the overall health impact of limiting protein intake in older persons with mild or moderate CKD, and whether this impact is different in older adults without CKD, is available.”

The authors analyzed data from three cohorts from Spain and Sweden that included 8543 participants aged at least 60 years. A total of 14,399 observations were analyzed, including 4789 participants with CKD stages 1-3 and 9610 without CKD. To capture protein intake over a longer period and minimize variations among individual study participants, the researchers arranged the data so that there was one observation per time interval for each participant. During the 10-year follow-up, 1468 deaths were documented.

“We observed an inverse association between total protein intake and mortality among participants with CKD but a somewhat weaker one than among those without CKD,” the researchers wrote.

Slightly Weaker Association

Compared with participants with a protein intake of 0.8 g/kg/day, participants with CKD who consumed 1.0 g/kg/day of protein had a 12% reduced risk for death. At an intake of 1.2 g/kg/day, the mortality risk decreased by 21%. It decreased by 27% at a protein intake of 1.4 g/kg/day. In patients without CKD, the corresponding risk reductions were 23%, 37%, and 44%.

While in participants without CKD, mortality decreased by 15% with each increase in protein intake of 0.2 g/kg/day, in patients with CKD, the decrease was only 8%.

The association did not change according to whether the protein was of animal or plant origin. The age of the study participants (ie, whether they were under or over age 75 years) also did not play a role.

Benefits Outweigh Drawbacks

The researchers pointed out that the biological effects of protein sources could depend on the total intake, as well as the proportion of plant protein in the diet. “Not only did 68% of total protein come from animal sources in our study, but also the mean protein intake was well above the current recommendations for persons with moderate CKD,” they wrote. It is therefore unclear whether the results could be extrapolated to older patients who follow a plant-based or low-protein diet.

“The stronger associations in participants without CKD suggest that the benefits of proteins may outweigh the downsides in older persons with mild or moderate CKD,” the researchers concluded.

This story was translated from the Medscape German edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.