Exploratory serum renal biomarker and eGFR responses to high-protein diets during resistance versus concurrent training in resistance-trained men.
Reza Bagheri, Zohreh Karimi, Hamid Ghobadi et al.
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In 30 seconds
This randomized 2 × 2 factorial trial examined renal biomarkers and estimated glomerular filtration rate (eGFR) in resistance-trained men consuming 1.6 or 3.2 g·kg⁻¹·d⁻¹ of protein during 16 weeks of resistance or concurrent training. Among 44 participants with complete data, there were no statistically significant protein-by-time or protein-by-training-by-time interactions for any renal measure (all p ≥ 0.182). BUN and cystatin C rose and eGFR estimates fell within both high-protein groups, but these descriptive changes did not establish differences from moderate protein intake.
Key findings
- No significant Time × Protein or Time × Training × Protein interactions were found for renal biomarkers or eGFR estimates (all p ≥ 0.182).
- In both 3.2 g·kg⁻¹·d⁻¹ groups, BUN and cystatin C increased (all p ≤ 0.017), while eGFR estimates decreased (all p ≤ 0.009).
- The BUN/creatinine ratio was unchanged (p ≥ 0.614); no significant within-group changes occurred in the 1.6 g·kg⁻¹·d⁻¹ groups.
Why it matters
The findings help contextualize renal laboratory changes during high-protein diets in resistance-trained men: changes in BUN, cystatin C, and estimated filtration within high-protein groups were not accompanied by statistically significant differences versus moderate protein intake. This distinction matters when interpreting biomarker shifts, while the study does not establish that high protein intake has no clinically meaningful renal effects.
What to keep in mind
The analyzed sample was limited to 44 men, and the authors state that this limits the ability to exclude clinically meaningful differences. Follow-up was 16 weeks.