Evaluation of the long-term effects of a high-protein diet on kidney function utilizing ultrasound elastography and kidney function tests in bodybuilders

Abstract

BACKGROUND: Bodybuilding athletes are more prone than other athletes to use high-protein diets. It is considered that a high-protein diet considerably affects renal functioning. This study examined the effects of a high-protein diet on the kidney function and morphology of bodybuilders over time. METHODS: Thirty-six male bodybuilders who trained an average of 3.5-6.5 hours a week for the previous two years participated in the study. Participants were separated into three groups based on their daily protein intake/body weight: group 1 (N.=8): 1.5-1.9 g/kg/day, group 2 (N.=16): 2-2.9 g/kg/day, and group 3 (N.=12): 3-4.5 g/kg/day. Blood urea nitrogen (BUN), serum creatinine (Cr), and estimated glomerular filtration rate were measured (eGFR). In urine samples, the amounts of microalbumin, calcium, sodium, chloride, and potassium were analyzed. Sonography was employed in order to assess renal parameters, cortical thickness, and cortical echogenicity. Share wave elastography was used to calculate share wave velocity for each kidney (SWV). RESULTS: In all protein intake groups, kidney volume, cortical echogenicity, and cortical thickness were shown to be significantly increased (P0.005). The group with the highest protein consumption had sonographic measurements that were considerably greater than the other groups (P0.005). All protein intake groups had significantly higher levels of eGFR, BUN, and the BUN/cr ratio than the control group and the reference values. None of the athletes had symptoms and indicators of renal failure. There were no statistically significant differences in SWV across all comparisons (P0.005). CONCLUSIONS: This study suggests that a high-protein diet has dose-dependent structural and functional effects on the kidneys. Traditional kidney function tests and ultrasound findings are nonspecific because they cannot distinguish between metabolic adaptation and the onset of a pathological process. Radiologists should be aware of the kidney effects of high protein diet and should guide the athletes about the importance of follow-up.