Chicken and fish diet reduces glomerular hyperfiltration in IDDM patients

Area of Science:

• Nephrology
• Endocrinology
• Nutritional Science

Background:

• Insulin-dependent diabetes mellitus (IDDM) can lead to kidney complications, including changes in glomerular filtration rate (GFR).
• Dietary protein intake is a known factor influencing kidney function in diabetic patients.

Purpose of the Study:

• To compare the effects of a low-protein diet (LPD) versus a normal protein diet (NPD) featuring chicken and fish (instead of red meat) on GFR in normoalbuminuric IDDM patients.
• To assess GFR changes in both normofiltering and hyperfiltering IDDM subgroups.

Main Methods:

• A crossover randomized clinical trial involving 15 normoalbuminuric IDDM patients (9 normofiltering, 6 hyperfiltering).
• Patients followed three diets for 3 weeks each: usual diet (UD), LPD (0.5 g/kg/day protein), and NPD (chicken/fish replacing red meat).
• GFR was measured using the 51Cr-EDTA single injection technique; urinary albumin excretion (UAE) and plasma amino acids were also assessed.

Main Results:

• Both LPD and NPD significantly reduced GFR in all diabetic patients compared to the UD (P=0.001).
• In hyperfiltering patients, both LPD and NPD significantly decreased GFR (P<0.001), with similar reductions between the two diets.
• No significant GFR changes were observed in normofiltering patients; metabolic control, BP, and UAE remained unchanged across all diets.

Conclusions:

• A normal protein diet, using chicken and fish as the sole meat protein sources, effectively lowers GFR in hyperfiltering, normoalbuminuric IDDM patients.
• The GFR-lowering effect of this normal protein diet is comparable to that of a low-protein diet.