Effect of a high-protein diet on kidney function in healthy adults: results from the OmniHeart trial

Consumption of a diet high in protein can cause glomerular hyperfiltration, a potentially maladaptive response, which may accelerate the progression of kidney disease.

An ancillary study of the OmniHeart trial, a randomized 3-period crossover feeding trial testing the effects of partial replacement of carbohydrate with protein on kidney function.

Healthy adults (N=164) with prehypertension or stage 1 hypertension at a community-based research clinic with a metabolic kitchen.

Participants were fed each of 3 diets for 6 weeks. Feeding periods were separated by a 2- to 4-week washout period. Weight was held constant on each diet. The 3 diets emphasized carbohydrate, protein, or unsaturated fat; dietary protein was either 15% (carbohydrate and unsaturated fat diets) or 25% (protein diet) of energy intake.

Fasting serum creatinine, cystatin C, and β2-microglobulin levels, estimated glomerular filtration rate (eGFR).

Serum creatinine, cystatin C, and β2-microglobulin collected at the end of each feeding period.

Baseline cystatin C-based eGFR was 92.0±16.3 (SD) mL/min/1.73 m(2). Compared with the carbohydrate and unsaturated fat diets, the protein diet increased cystatin C-based eGFR by ~4 mL/min/1.73 m(2) (P < 0.001). The effects of the protein diet on kidney function were independent of changes in blood pressure. There was no significant difference between the carbohydrate and unsaturated fat diets.

Participants did not have kidney disease at baseline.

A healthy diet rich in protein increased eGFR. Whether long-term consumption of a high-protein diet leads to kidney disease is uncertain.