The effect of dietary protein on glomerular filtration rate in normal subjects.

The acute effect of the ingestion of 90 g of protein as meat and as milk protein (Casilan) on glomerular filtration rate (assessed by creatinine clearance) was examined in healthy subjects. The creatinine clearance increased 1.5 hours after the ingestion of meat and remained elevated for a further 2.5 hours. The mean maximal increase in creatinine clearance was 18 ml/min. Casilan on the other hand did not produce a significant increase in the creatinine clearance. When 6 subjects ingested 90 g of protein as Casilan daily for 5 days, the creatinine clearance increased after a delay of 3 to 4 days. When the same subjects increased their meat protein intake by 90 g as meat daily for 5 days, the creatinine clearance increased from the first day (by 23 ml/min) and remained elevated throughout the 5 days of study. We conclude that the effect of protein on glomerular filtration rate depends on the type of protein.