New Study Investigates the Link Between High-Protein Diets and Kidney Health

High-protein diets may increase kidney workload, but effects on kidney health appear to depend on kidney function and diet quality, according to a review published in Nutrients.

Protein is essential for muscle maintenance. However, higher protein intake can temporarily increase glomerular filtration rate (GFR), a process known as hyperfiltration. This response may occur after a high-protein meal.

Animal studies suggest that prolonged excessive protein intake can stress the kidneys. In rodents, high-protein diets have been linked with hyperfiltration, proteinuria, enlargement of kidney structures, fibrosis and glomerulosclerosis. These effects were more severe in animals with reduced kidney mass or chronic kidney disease (CKD).

However, the researchers caution that these findings cannot be applied to humans because animals may receive much higher protein loads and have different metabolic responses.

Human evidence is mixed. Some studies suggest that higher intake of animal protein, particularly from processed and red meat, may be associated with greater CKD risk, while plant-based dietary patterns appear more favourable or neutral. However, these findings may reflect diet quality rather than protein source alone.

For people without CKD, higher protein intake has been associated with increased eGFR, consistent with hyperfiltration, but this does not necessarily indicate kidney damage. Evidence on whether high protein intake causes harm in healthy kidneys remains limited.

For people with CKD, the situation is different. Evidence suggests that moderate protein restriction may slow eGFR decline and CKD progression, although certainty remains low to moderate. At the same time, excessive restriction can increase the risk of muscle loss, in older adults.

The review supports an individualized approach to protein intake. People with CKD should have protein requirements tailored to kidney function, age, nutritional needs and disease stage rather than following a high- or low-protein diet without guidance.

REFERENCE: Jacuńska, J., Bruciak, A., Wilk, J., et al. (2026). High-Protein Intake Impact on Human and Animal Kidney Function Across the Lifespan: Clinical Evidence and Emerging Concepts. Nutrients 18(19); 3209. DOI: 10.3390/nu18193209.