Protein Intake Not Linked to GFR Decline in Adults Without CKD, Suggests Research
Norway: Researchers have found in a new study that among adults without chronic kidney disease, moderate-to-high habitual protein intake was not associated with a decline in iohexol-measured GFR. The study has been published in Clinical Kidney Journal. However, further research is needed to determine whether the source and type of dietary protein influence long-term kidney function.
Concerns have been raised that high protein consumption may increase the workload on the kidneys by raising intraglomerular pressure and promoting hyperfiltration. Although protein restriction is recommended in advanced CKD in some settings to reduce glomerular stress, whether limiting protein can prevent CKD in otherwise healthy adults remains uncertain. Previous studies have also largely used estimated GFR, which can be affected by factors unrelated to actual filtration.
The study by Ludvig Balteskard Rinde of the Metabolic and Renal Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway, and colleagues examined this question using directly measured kidney function.
Researchers analysed data from 1,324 adults participating in the Renal Iohexol Clearance Survey, a population-based cohort with repeated measurements of GFR. Participants were aged 40 years or older and were followed for a median of 10 years. Dietary protein intake at baseline was assessed using a validated food-frequency questionnaire, and kidney function was measured by iohexol clearance.
The participants had a mean age of 64 years, half were women, and average baseline measured GFR was 89 ml/min/1.73 m². Mean reported protein intake was 1.2 g/kg/day. Participants in the lowest protein-intake group consumed less than 0.9 g/kg/day, while those in the highest group consumed at least 1.4 g/kg/day.
The analysis found no meaningful relationship between habitual protein intake and deterioration in measured kidney function.
- Each additional 0.1 g/kg/day of protein intake was associated with a GFR change of −0.01 ml/min/1.73 m² per year.
- Higher protein consumption was not linked to accelerated GFR decline.
- Protein intake was also not associated with development of measured GFR below 60 ml/min/1.73 m².
- The findings remained consistent across different analytical and sensitivity assessments.
The researchers noted that the results do not support routinely targeting moderate-to-high protein consumption as a major risk factor for CKD development among adults without established kidney disease. The findings may also help inform dietary counselling for people with normal kidney function who consume protein within commonly observed ranges.
However, the study assessed self-reported protein intake at baseline and cannot establish whether specific protein sources or dietary patterns have different effects on kidney health. Overall, the 10-year findings suggest that habitual protein restriction may not be an effective lifestyle strategy for preventing CKD in the general adult population.
Reference:
Rinde, L. B., Hopstock, L. A., Lundblad, M. W., Rinde, N. B., Brobak, K. M., Norvik, J. V., Enoksen, I. T., Solbu, M. D., Fuskevåg, O. M., Carrero, J. J., Carlsen, M. H., Eriksen, B. O., & Melsom, T. (2026). Higher habitual protein intake is not linked to decline of iohexol-measured GFR in adults ≥40 years. Clinical Kidney Journal, 19(8). https://doi.org/10.1093/ckj/sfag235
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