**3.6. Protein**

Higher protein intake is associated with higher bone mass density, decrease in bone loss, and increase in muscle mass and strength [67–70]. An epidemiologic study reported that higher protein intake decreased health problems in older women [71]. The ADA suggests normal protein intake (15–20% of daily energy) in patients with normal renal function. The data about the safety of high-protein intake are scanty. However, a recent study reported that high-protein diet (approximately 30% of daily energy) provided less glucose-lowering medications after 1 year in elderly type 2 diabetic patients [72]. Kidney Disease Outcomes Quality Initiative of the American National Kidney Foundation (KDOQI) guidelines recommend a daily protein intake of 0.8 g/kg in diabetic patients with chronic kidney disease (CKD); however, there is little evidence related to adults older than 75 years. The results of 5-year prospective cohort study showed that higher daily protein intake (about 1.1 g/kg/day) did not decrease kidney function [73]. Low-protein intake might be associated with a decrease in muscle mass in CKD patients. Therefore, daily energy intake of 30 kcal/kg should be recommended to keep a neutral nitrogen balance [74].
