EFFECTS OF A HIGH-PROTEIN INTAKE ON RENAL ACID EXCRETION IN BODYBUILDERS

Bodybuilders often prefer a high protein diet to achieve maximum skele tal muscle hypertrophy. In this study the effect of a high protein die t on renal acid load and renal handling of proton excretion was studie d comparing dietary intake and urinary ionograms in 37 male bodybuilde rs and 20 young male adults. Energy intake (+ 7 %), protein intake (12 8 vs 88 g/d/1.73 m(2)), and renal net acid excretion (95 vs 64 mmol/d/ 1.73 m(2)) were higher in the bodybuilders than in the controls, howev er, urine-pH was only slightly lower (5.83 vs 6.12). In the bodybuilde rs renal ammonium excretion was higher at any given value of urine pH than in the controls. In a regression analysis protein intake proved t o be an independent factor modulating the ratio between urine-pH and r enal ammonium excretion. The concomitant increase of renal net acid ex cretion and maximum renal acid excretion capacity in periods of high p rotein intake appears to be a highly effective response of the kidney to a specific food intake leaving a large renal surplus capacity for a n additional renal acid load.