Although human kidneys age better than other fundamental organs, such as the heart and brain, their decline in structure and function increases the susceptibility of healthy subjects as well as those with chronic disease to drugs and electrolyte abnormalities during stressful conditions. Chronic kidney diseases (CKD) and their progression to end-stage renal disease (ESRD) are considerable social and economic problems in all industrialized countries.
Each year in Italy, more than 18,000 patients are diagnosed as having CKD, and about a half million Italians have serum creatinine levels higher than 1.5 mg/dL. The incidence of CKD is strictly linked to age. A French epidemiological study indicated that the CKD incidence in patients over 75 years was almost 7 times that in patients aged 20-39 years and more the twice that in patients aged 40-59 years. Therefore, interventions that may prevent the development of CKD in middle age and the progression of CKD to ESRD are very important for public health.
Restricting protein in the diet of pregnant mice results in reduced numbers of nephrons in newborn animals greater than 30%. Low (LPD) or very low (VLPD) protein diets have been widely used, first for treating uremia and then to prevent the progression of CKD, but recently, a meta-analysis of existing data concluded that there is no evidence that LPD or VLPD diets have any effect in reducing the progression of kidney disease in diabetic nephropathy, and very often some degree of dangerous protein malnutrition occurs in these patients.