The effect of protein restriction on the progression of renal insufficiency. Randomised multicentre study of a low-protein diet on the progression of chronic renal failure in children. European Study Group of Nutritional Treatment of Chronic Renal Failure in Childhood. Effect of dietary protein restriction on prognosis in patients with diabetic nephropathy. Effect of moderate dietary protein restriction on the progression of overt diabetic nephropathy: a 6-mo prospective study. Effect of restricting dietary protein on the progression of renal failure in patients with insulin-dependent diabetes mellitus. Effect of mid-day meal programme on physical growth & mental function. Supplementation with human milk protein improves growth of small premature infants fed human milk. Severe dietary protein restriction in overt diabetic nephropathy: benefits or risks? Resistance training to counteract the catabolism of a low-protein diet in patients with chronic renal insufficiency. A randomized, controlled trial.
Dietary protein intake may be an important determinant of the rate of decline in renal function in patients with chronic renal insufficiency. We conducted a prospective, randomized study of the efficacy of protein restriction in slowing the rate of progression of renal impairment. The study lasted 18 months and included 64 patients with serum creatinine concentrations ranging from 350 to 1000 micromol per liter. The patients were randomly assigned to follow either a regular diet or an isocaloric protein-restricted diet (0.4 g of protein per kilogram of the body weight per day). Blood-pressure levels and the balance between calcium and phosphate were similar in the two groups. End-stage renal failure developed in 9 of the 33 patients (27 percent) who followed the regular diet during the study, as compared with 2 of the 31 patients (6 percent) who followed the protein-restricted diet (P less than 0.05). The mean (+/- SE) glomerular filtration rate, as measured by the clearance of 51Cr bound to EDTA, fell from 0.25 +/- 0.03 to 0.10 +/- 0.05 ml per second (P less than 0.01) in the group on the regular diet, whereas it fell from 0.23 +/- 0.04 to 0.20 +/- 0.05 ml per second (P not significant) in the group on the protein-restricted diet. We conclude that dietary protein restriction is effective in slowing the rate of progression of chronic renal failure. Some studies have suggested that a low-protein diet slows the deterioration of renal function in patients with chronic renal failure (CRF). The effects of a low-protein diet on renal function and growth, have not been assessed in a large, prospective randomised trial in children with CRF.
                A 2-year prospective, stratified, and randomised multicentre study recruited 191 patients aged 2-18 years. After a run-in period of at least 6 months, patients were stratified into either a progressive or non-progressive category based on the change in creatinine clearance in this period. The patients were also stratified into three renal-disease categories and then randomly assigned to a control or diet group. In the diet group, the protein intake was the lowest, safe WHO recommendation--i.e., 0.8-1.1 g/kg daily adjusted for age. All patients were advised to have a calorie intake of at least 70% of the WHO recommendations. Glomerular filtration rate (GFR) was measured every 2 months by creatinine clearance; dietary compliance was checked by urinary urea-nitrogen excretion and dietary diaries (weighing method). 112 patients completed an optional third year of the study.
                The low-protein diet did not affect growth. However, there was no effect of diet on the mean decline in creatinine clearance over 2 years (diet vs control: progressive group -9.7 [SD 8.0] vs -10.7 [11.8] mL/min per 1.73 m2; non-progressive group -2.5 [7.5] vs -4.3 [10.0] mL/min per 1.73 m2). Patients classified as having progressive disease were older and had a lower creatinine clearance and a higher blood pressure at randomisation, and had a greater decrease in creatinine clearance than non-progressive patients. On multivariate regression analysis proteinuria (partial R2 = 0.259) and systolic blood pressure (partial R2 = 0.087) were independent predictors of the change in GFR. Similar results were found after the study was extended for a third year.
                A low-protein diet for 3 years did not affect the decrease in renal function in children with CRF. Proteinuria and blood pressure explain a large part of the variability of, and may be causally related to the decline in the GFR. Recent data suggest that dietary protein restriction improves survival and delays the progression to end-stage renal disease (ESRD) in non-diabetic nephropathies. The purpose of our study was to determine the effect of dietary protein restriction on survival and progression to ESRD in diabetic nephropathy.
                A four-year prospective, controlled trial with concealed randomization was performed comparing the effects of a low-protein diet (0.6 g/kg/day) with a usual-protein diet. The study included 82 type 1 diabetic patients with progressive diabetic nephropathy [pre-study mean decline in glomerular filtration rate (GFR) 7.1 mL/min/year (95% CI, 5.8 to 8.5)]. The main outcome measures were decline in GFR and development of ESRD or death.
                During the follow-up period the usual-protein diet group consumed 1.02 g/kg/day (95% CI; 0.95 to 1.10) as compared with 0.89 (0.83 to 0.95) in the low-protein diet group (P = 0.005). The mean declines in GFR were 3.9 mL/min/year (2.7 to 5.2) in the usual-protein diet group and 3.8 (2.8 to 4.8) in the low-protein diet group. ESRD or death occurred in 27% of patients on a usual-protein diet as compared with 10% on a low-protein diet (log-rank test; P = 0.042). The relative risk of ESRD or death was 0.23 (0.07 to 0.72) for patients assigned to a low-protein diet, after an adjustment at baseline for the presence of cardiovascular disease (P = 0.01). Blood pressure and glycemic control were comparable in the two diet groups during the follow-up period.
                Moderate dietary protein restriction improves prognosis in type 1 diabetic patients with progressive diabetic nephropathy in addition to the beneficial effect of antihypertensive treatment. To assess whether moderate dietary protein restriction can delay the progression of overt diabetic nephropathy, 22 subjects with insulin-dependent diabetes mellitus were randomly assigned to an unrestricted protein diet (> 1.6 g.kg body wt-1.d-1) or a moderately protein-restricted diet (0.8 g.kg body wt-1.d-1) and followed prospectively for six mo. Direct isotope methods were used to assess renal function. Protein intake was assessed by measurement of urinary urea nitrogen. The two groups were well-matched for age, sex, duration of diabetes, glycemic control, blood pressure, and degree of renal insufficiency. Patients consuming the unrestricted protein diet (n = 11) showed a progressive decline in glomerular filtration rate of 1.3 mL.min-1.mo-1 with no change in proteinuria. Patients consuming the moderately protein-restricted diet showed a marked decrease in the degree of proteinuria (2.15-1.13 g/d, P = 0.036) and a stabilization of glomerular filtration rate. This occurred independently of changes in blood pressure or glycemic control. Moderate dietary protein restriction can ameliorate progression of overt diabetic nephropathy. Restriction of dietary protein may slow the progression of renal failure in diverse renal diseases, but the extent to which such a diet is beneficial in patients with diabetic nephropathy is uncertain.
                We studied the effect of reduced intake of protein and phosphorus on the progression of renal disease in 35 patients with insulin-dependent (Type I) diabetes mellitus and clinically evident nephropathy. The low-protein, low-phosphorus diet contained 0.6 g of protein per kilogram of ideal body weight per day, 500 to 1000 mg of phosphorus, and 2000 mg of sodium. The control diet consisted of the patient's prestudy diet with the stipulation that it contain 2000 mg of sodium and at least 1 g of protein per kilogram per day and 1000 mg of phosphorus. Renal function was assessed by measurement of iothalamate and creatinine clearances at intervals of 3 to 6 months, and the patients were followed for a minimum of 12 months (mean, 34.7). The declines in mean glomerular filtration rates were compared between groups by linear-regression analysis of the glomerular filtration rate as a function of time.
                The patients who followed the study diet for a mean of 37.1 months had declines in iothalamate clearance of 0.0043 ml per second per month and in creatinine clearance of 0.0055 ml per second per month. The comparable values in the control group were 0.0168 and 0.0135, respectively (P less than 0.05). Blood pressure was well controlled, and the degree of glycemic control was comparable in both groups.
                Dietary restriction of protein and phosphorus can retard the progression of renal failure in patients with Type I diabetes mellitus who have nephropathy. We believe that wider use of this treatment is indicated. The effect of food supplementation in rural primary school children was studied on physical growth and mental functions. Children (146) received 450-500 calories with 10-12 g of protein for an average of 172 days a year, for 2 yr (1984-1986). Height was found not to differ significantly in the supplemented group as compared to controls. However, there was marginally better weight gain. More children in the supplemented group remained in grade I in contrast to the controls who shifted to grade II nutritional status after 2 yr. Children receiving the supplementation showed marginal increment in full scale, verbal and performance IQ. The improvement was significant for all subtests except for comprehension and maze tests. The observations on unstructured Piagetian developmental tasks also indicated that the performance of children on task conservation of liquid was improved marginally after supplementation. However, on Bender Gestalt test, no change was observed. The scores on arithmetic achievement test showed improvement of 12-14 points in the supplementation group. It appears that nutrition supplementation is beneficial for better school attendance, and reduction in the drop out rate; it also improves intelligence and cognitive function to a marginal extent. However, as this age group falls in the slow growth period, no catch up was observed in physical growth. We investigated the influence of human milk protein and medium-chain triglyceride supplementations of human milk feedings on the growth of very low birth weight infants during their first weeks of life. A group of 44 preterm infants with birth weights of less than 1,520 g and a mean gestational age of 30.3 weeks was randomly divided into four groups to receive plain human milk or human milk supplemented with human milk protein (0.9 g/dL), with medium-chain triglycerides (1 g/dL), or with both. The medium-chain triglyceride oil supplementation did not influence the growth of these infants. The infants given supplementary protein gained weight faster during weeks 4 to 6 than those without (18.5 +/- 0.7 v 15.1 +/- 0.6 g/kg/d; mean +/- SEM; P = .001). After 4 weeks of age the infants given supplementary protein had a mean weight gain equal to the mean intrauterine rate, in contrast to the infants of the other groups, who grew more slowly until age 6 weeks. Furthermore, we found a correlation between serum albumin concentration and weight gain during the seventh week of life (P = .018). The length growth velocity for the infants with protein supplementation was 0.99 +/- 0.06 cm/wk (mean +/- SEM) and for those without 0.83 +/- 0.05 cm/wk (P = .043). There was no difference in growth of head circumference between the groups. We conclude that human milk protein supplementation improves the growth of small premature infants fed human milk, and that the protein concentration of bank milk is insufficient for their adequate growth. To evaluate whether restricting protein intake may delay the progression of chronic renal failure caused by overt diabetic nephropathy and also whether this increases the risk of malnutrition.
                Prospective clinical trial.
                Nephrology outpatients.
                Sixty-nine patients (32 affected by type 1 and 37 by type 2 diabetes, all treated with insulin) affected by both overt diabetic nephropathy and hypertension.
                The study was started once hypertension and glycemia had been under control for at least 3 months. Two groups of patients, matched for similar mean glomerular filtration rate value and nutritional status, were studied: a low-protein diet (0.6 g/kg/d) was randomly prescribed to 35 patients, whereas in the other 34 patients a free diet intake was maintained for 12 months.
                Renal function and nutritional status.
                The protein intake was significantly different in the 2 groups of patients, whereas the average decline of glomerular filtration rate during the follow-up was comparable. In the low-protein diet group, serum prealbumin concentration significantly decreased after 9 months, whereas serum albumin decreased at the end of the study.
                Severe dietary protein restriction does not seem to delay the progression of renal disease in patients with overt diabetic nephropathy, whereas it may induce malnutrition.
                Copyright 2002 by the National Kidney Foundation, Inc. Chronic renal insufficiency leads to muscle wasting, which may be exacerbated by low-protein diets prescribed to delay disease progression. Resistance training increases protein utilization and muscle mass.
                To determine the efficacy of resistance training in improving protein utilization and muscle mass in patients with chronic renal insufficiency treated with a low-protein diet.
                Randomized, controlled trial.
                Tufts University, Boston, Massachusetts.
                26 older patients with moderate renal insufficiency (17 men, 9 women) who had achieved stabilization on a low-protein diet.
                During a run-in period of 2 to 8 weeks, patients were instructed and their adherence to the low-protein diet (0.6 g/kg of body weight per day) was evaluated. They were randomly assigned to a low-protein diet plus resistance training (n = 14) or a low-protein diet alone (n = 12) for 12 weeks.
                Total body potassium, mid-thigh muscle area, type I and II muscle-fiber cross-sectional area, and protein turnover.
                Mean protein intake was 0.64 +/- 0.07 g/kg per day after stabilization. Total body potassium and type I and II muscle-fiber cross-sectional areas increased in patients who performed resistance training by a mean (+/-SD) of 4% +/- 8%, 24% +/- 31%, and 22% +/- 29%, respectively, compared with those who did not. Leucine oxidation and serum prealbumin levels also improved significantly. Patients assigned to resistance training maintained body weight compared with those who were not. Improvement in muscle strength was significantly greater with resistance training (32% +/- 14%) than without (-13% +/- 20%) (P < 0.001).
                By improving muscle mass, nutritional status, and function, resistance training seems to be effective against the catabolism of a low-protein diet and uremia in patients with renal failure.
Reducing protein intake does not appear to have significant impact in delaying the progression to ESKD in children.