EFFECTS OF MODERATE CHANGES IN PROTEIN-INTAKE ON URINARY ALBUMIN EXCRETION IN TYPE-I DIABETIC-PATIENTS

We investigated the short-term effects of moderate increments or decre ments of protein intake on albumin excretion rates of type I diabetic patients. Ten normotensive patients with either normal albumin excreti on rates (<20 mu g/min, group I, n = 5) or persistent mu-albuminuria ( 20-200 mu g/min, group II, n = 5) were fed successively three test die ts providing different protein intakes. Each patient was randomly allo cated to 3-wk sequences of the following diets: low-protein diet (LPD; median 0.84, range 0.76-0.94 g . kg(-1) .) day(-1)), medium-protein d iet (MPD; median 1.33, range 0.98-2.00 g . kg(-1) . day(-1)), and high -protein diet (HPD; median 2.05, range 1.54-2.61 g . kg(-1) . day(-1)) . The three diets were isoenergetic and isoglucidic. In group I patien ts, no consistent change was found in mu-albuminuria. In group n patie nts, LPD resulted in a reduction in mu-albuminuria compared with MPD a nd HPD. Changes in albumin excretion rates were positively correlated to relative changes in protein intake. This suggests that moderately p rotein-restricted diets can reduce mu-albuminuria in diabetic patients suffering from incipient nephropathy, the degree of reduction dependi ng on the degree of restriction. Because of poor patient compliance wi th protein intakes <0.8 g . kg(-1) . day(-1), we conclude that moderat ely rather than severely protein-restricted diets should be recommende d for long-term prescriptions.