This is a myth!
Higher protein (HP) diets (above RDA recommendations) have been used to promote weight loss, preserve muscle mass, and prevent sarcopenia. However, there is a myth that higher protein diets lead to kidney dysfunction. The indicator would be a change in glomerular filtration rate (GFR).
It turns out that the data does not support such a myth.
A meta-analysis conducted by Phillips et al. looked at higher protein diets (≥1.5 g/kg body weight or ≥20% energy intake or ≥100 g protein/d) and their effects on kidney function. When compared to normal- or lower-protein (NLP; ≥5% less energy intake from protein/d) diets, HP diets resulted in higher GFR overall; however HP intake did not influence changes in GFR. Thus, it was concluded that HP intake does not negatively influence renal function in healthy adults.
A systematic review of randomized control trials and epidemiologic studies conducted by Elswyk et al found that HP intake (≥20% but <35% of energy or ≥10% higher than a comparison intake) had little to no effect on blood markers of kidney function (i.e., blood pressure) when compared to groups following US RDA recommendations (0.8 g/kg or 10-15% of energy).
Coming from the PROT-AGE study group, “both endurance- and resistance-type exercises are recommended at individualized levels that are safe and tolerated, and higher protein intake (i.e., ≥ 1.2 g/kg body weight/d) is advised for those who are exercising and otherwise active. Most older adults who have acute or chronic diseases need even more dietary protein (i.e., 1.2-1.5 g/kg body weight/d).” However, individuals with severe kidney disease (GFR <30 mL/min/1.73 m(2)), but who are not on dialysis, are an exception to the rule; this cohort may need to limit protein intake.
Our goal is to optimize. According to Schoenfeld et al., reaching the minimum threshold of 1.6 g/kg spread out evenly throughout the day is necessary to maximize anabolism.