Nutrition therapy in renal disease.

Dietary therapy in chronic renal insufficiency has as its principle aim preservation of residual renal function and to a lesser extent addresses metabolic abnormalities--notably relating to calcium, phosphorus, and vitamin D. Assuring an adequate calorie intake and determining a safe low level of protein and phosphorus are therapeutic goals. Dietary therapy in chronic renal failure emphasizes the goal of avoiding the metabolic problems--particularly those relating to excess dietary protein and phosphorus. Lowering protein and phosphorus to levels at or below the recommended level for normal adults has beneficial effects. However the issue of what level of intake is adequate or safe has not been fully addressed. While comparable studies in infants and children are more difficult, the effects of lower intakes upon growth are a rigorous test of adequacy or safety for this therapy.

Nutritional aspects of renal disease in children and adults.

Renal disease tends to exact a greater nutritional toll in children than in adults because the needs for growth and development and differences in body composition impose a greater excretory load on the child's kidneys. Tubular disorders disturb body composition in specific ways and mandate individualized dietary supplementation or restriction. Management approaches are outlined.

Nutritional management of chronic renal disease.

The importance of nutritional evaluation and diet therapy in the overall management of the patient with chronic renal disease is unquestioned. Its application often is limited by a lack of knowledge regarding the requirement for certain nutrients in health as well as the way in which these requirements are modified by chronic disease. However, the most important and often the most difficult task is engaging the cooperation of the patient in the nutritional management of his disease. Acceptance of dietary manipulation depends upon the patient's family structure and the importance of food and mealtime within the particular cultural and ethnic background. Dietary recommendations implemented by the parents of pediatric patients may produce untoward changes in the child's behavior, attitudes toward food, or relationships with other family members. Dietary recommendations must be carefully planned and their effect reevaluated. They should be individualized to the age, intellectural skills, and developmental stage of the patient.

The effect of energy and nitrogen intake upon urea production in children with uremia and undernutrition.

Children with severe uremia who had anorexia were observed in a clinical study center where dietary energy and nitrogen intake could be compared with urea nitrogen production (UNPr). The children received a supplement of dextrose and amino acids at night, ate a self-selected diet and were encouraged to use carbohydrate supplements. Energy intake varied from 22 to 110 kcal/kg/day and nitrogen intake from 105 to 323 mg/kg/day. UNPr was reciprocally related to energy intake. Nitrogen intake minus UNPr, an index of nitrogen balance, was positively related to energy intake. UNPr was not related to nitrogen intake. Nitrogen intake (NI) and NI-UNPr were correlated and the slope of the regression was 1.15. We inferred from the data that low energy intakes (less than 60 kcal/kg/day) were associated with catabolic losses of body protein. Intakes above that level were associated with a low and stable rate of UNPr. The level of energy and nitrogen intake within the range observed limited the rate of nitrogen retention. Once maintenance requirements for energy and nitrogen were satisfied, the efficiency with which nitrogen was used for net protein synthesis was very high.

Improved growth in growth retarded uremic rats with use of calorie supplementation.

Renal failure in childhood is often associated with poor growth. Growth in uremia was studied using young growing male Sprague-Dawley rats made moderately uremic (SUN77 mg/100 ml) by partial nephrectomy. Uremic rats weighed less than control rats after 17 days of observation (P less than .01). Uremic rats supplemented by corn oil gavage had significantly better weight gain than nonsupplemented uremic rats (P less than .005). Uremic rats whose appetite was stimulated by the addition of saccharin to diet also had significantly better daily weight gain than uremic rats not having saccharin added to diet (P less than .05). Calorie intake appeared to be the limiting variable with regard to observed differences in growth. In fact, when adjusted for calorie intake/weight-75, uremic rats did not differ from control rats in weight gain/weight-75. In addition, control rats fed diets identical to those consumed by uremic rats grew equally as poorly. Improved growth in uremic rats with calorie supplementation was felt to be real growth in that body composition studies showed proportionate gains in cell mass, total body solids, liver and muscle. Catch-up growth was not observed, perhaps because insufficient supplemental calories were provided or because other unexplained factors contributed to growth retardation.