Effect of a high-protein diet on kidney function in healthy adults: results from the OmniHeart trial.
Study Goal
The researchers aimed to determine the effects of a high-protein diet on kidney function, specifically glomerular filtration rate (eGFR), in healthy adults with prehypertension or stage 1 hypertension.
Results Summary
The high-protein diet increased cystatin C-based eGFR by approximately 4 mL/min/1.73 m² compared to carbohydrate and unsaturated fat diets, with no significant difference between the latter two diets. The effects were independent of blood pressure changes, but long-term implications for kidney disease risk remain uncertain.
Population
Healthy adults (N=164) with prehypertension or stage 1 hypertension.
Effective Dosage
25% of energy intake from protein (compared to 15% in the other diets).
Duration
6 weeks per diet, with 2- to 4-week washout periods between diets.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
diet high in protein | increase | glomerular hyperfiltration | - | - | can cause | #1 |
partial replacement of carbohydrate with protein | neutral | kidney function | Healthy adults (N=164) with prehypertension or stage 1 hypertension | - | testing the effects of | #2 |
protein diet (25% of energy intake) | increase | cystatin C-based eGFR | Healthy adults (N=164) with prehypertension or stage 1 hypertension | ~4 mL/min/1.73 m(2) | increased | #3 |
protein diet | neutral | kidney function | Healthy adults (N=164) with prehypertension or stage 1 hypertension | - | effects on | #4 |
carbohydrate and unsaturated fat diets | no change | kidney function | Healthy adults (N=164) with prehypertension or stage 1 hypertension | - | no significant difference between | #5 |
healthy diet rich in protein | increase | eGFR | - | - | increased | #6 |
BACKGROUND: Consumption of a diet high in protein can cause glomerular hyperfiltration, a potentially maladaptive response, which may accelerate the progression of kidney disease. STUDY DESIGN: 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. SETTING & PARTICIPANTS: Healthy adults (N=164) with prehypertension or stage 1 hypertension at a community-based research clinic with a metabolic kitchen. INTERVENTION: 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. OUTCOMES: Fasting serum creatinine, cystatin C, and β2-microglobulin levels, estimated glomerular filtration rate (eGFR). MEASUREMENTS: Serum creatinine, cystatin C, and β2-microglobulin collected at the end of each feeding period. RESULTS: 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. LIMITATIONS: Participants did not have kidney disease at baseline. CONCLUSIONS: A healthy diet rich in protein increased eGFR. Whether long-term consumption of a high-protein diet leads to kidney disease is uncertain.