Effects of aging on the renal glomerulus.

The biologic price of aging includes progressive deterioration of renal function and structure. After the age of 30, glomerular filtration and renal blood flow rates decline in a linear fashion, so that values in octagenarians are only half to two thirds those measured in young adults. Renal mass similarly declines, and the incidence of sclerotic glomeruli increases with advancing age. Accordingly, the aging kidney is at high risk of eventual failure when functioning nephron number is further reduced by acquired renal disease. Recent evidence suggests that limitation of dietary protein intake delays the development of age- and disease-related glomerular sclerosis in experimental animals, and that dietary protein restriction may postpone end-stage renal disease in patients with progressive renal insufficiency.