Role of amount and nature of carbohydrates in the course of experimental renal failure.

The renal effects of carbohydrates (CHO) were studied in two experiments. 1) The effects of CHO-energy restriction was evaluated by comparing uremic growing rats (initial weight: 80 g) fed "ad lib" (L rats) or CHO-restricted (starch and glucose) but receiving identical amounts of all other nutrients (R rats). R rats showed reduced growth, slower increase in plasma creatinine, lower mortality rate, and less histological renal damage than L rats. 2) Two types of CHO restriction, low glucose (R1 rats) or low starch (R2 rats) were compared to "ad lib" feeding (L1 rats) in adult rats (initial weight: 130 g). Growth was identically reduced in R1 and R2 rats. Mean plasma creatinine levels at week four was lower in R1 than in L1 rats. The overall rate mortality was higher for L1 and R2 than in R1 rats (79%, 81%, 53%) but included deaths from other causes than renal failure. Actuarial survival excluding these deaths was 27%, 83% and 10% in L1, R1 and R2 rats, respectively. Diffuse renal lesions were found in 25 of 30 L1, 5 of 15 R1, and 12 of 15 R2 rats (R1 vs. R1 and R2, P less than 0.01). The results show that CHO restriction may preserve the renal parenchyma, and suggest that restriction of "simple" rather than "complex" CHO restriction may be beneficial, a finding which could be of clinical importance if confirmed by further investigations.