Kidney Week

Abstract: FR-PO1106

Dietary Protein Intake and Kidney Function in US Adults: Evidence of a Modest Stepwise Association from NHANES, 2007-2020

Session Information

• Health Maintenance, Nutrition, and Metabolism
  November 07, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Health Maintenance, Nutrition, and Metabolism

• 1500 Health Maintenance, Nutrition, and Metabolism

Author

• Quintana, Mario, Ross University School of Medicine - Barbados Campus, Bridgetown, Saint Michael, Barbados

Mario Quintana

Background

High-protein diets are commonly discouraged in individuals with or at risk for chronic kidney disease (CKD), but evidence supporting population-wide protein restriction remains limited and inconsistent, particularly in adults without CKD

Methods

We analyzed 17,170 adults aged ≥18 from NHANES 2007–2020 with complete data on serum creatinine, urinary albumin-to-creatinine ratio (UACR), 24-hour dietary recall, and demographics. eGFR was calculated using the CKD-EPI equation. UACR was log-transformed for linear modeling. Protein intake (grams/day) was stratified into quintiles: Q1 (≤47g), Q2 (48–64g), Q3 (65–82g), Q4 (83–109g), and Q5 (≥110g). Linear regressions evaluated associations between protein intake and eGFR and log(UACR), adjusted for age, sex, race/ethnicity, and total caloric intake. Interaction terms were included to assess age-specific effects

Results

In adjusted models, higher protein intake was modestly associated with lower eGFR (β = –0.026 mL/min/1.73m² per gram; 95% CI: –0.032 to –0.020; p < 0.001). This corresponds to a ~2.6 mL/min/1.73m² lower eGFR for every 100g/day increase in protein intake. The association remained significant after adjusting for total caloric intake. Median eGFR declined slightly across protein quintiles (Figure 1). Age-stratified regression revealed a stronger inverse association in older adults (over >65). Protein intake was also associated with a minor reduction in log(UACR) (β = –0.0004; p < 0.01); though statistically significant, the effect was negligible in magnitude.

Conclusion

Among U.S. adults, higher protein intake is modestly associated with lower eGFR but not with increased albuminuria. The effect is more pronounced in older adults, suggesting that age may modify the renal response to dietary protein. These findings do not support broad protein restriction in healthy adults without CKD.

Higher Protein Intake Associated with Modestly Lower eGFR in a Dose-Dependent Fashion

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025xt8z1h1a