Metabolic, renal and bone effects of high-protein diets

The protective role of exercise

Abstract

The establishment of safe dietary protein intake reference levels for the general population as well as for athletes is under debate. There is evidence indicating a positive benefit of high protein diets (HP) on total cholesterol and triglycerides, and on promoting weight loss. The findings on the effect of HP diets on renal and bone metabolism are however contradictory. While there are studies that consider the renal glomerular hyperfiltration, caused by the consumption of HP diets, a normal adaptive physiological response, others find an increased risk of renal disease after chronic HP diets. Regarding bone metabolism, there are studies showing a worse bone mineral density after a HP diet, others that did not observe any effect on bone metabolism, or even a bone protective effect. Exercise is a key player in most of the HP diets-related effect on metabolic acidity, renal and bone health. There is compelling evidence that exercise positively influence blood lipid profile, renal inflammation and glomerular filtration rate, and stimulating bone mineral content and density. The study of Elango et al (2009) showed that recommended daily protein intake of 0.8 g/kg/day were undervalued, and thus they established new reference levels for the general population. There is still an urgent need to formulate safe protein intake recommendations for athletes of different disciplines.