AMINO-ACID SUPPLEMENTATION AND THE NUTRITIONAL-STATUS OF THE PREDIALYSIS PATIENT

Objectives. This study investigated the effect of the conventional low -protein diet compared with a very-low-protein diet supplemented with essential amino acids with regard to the nutritional status of the pre dialysis patient. Design. The study was designed as a randomised clini cal trial for intervention, Setting. The trial was conducted at the ne phrology outpatient clinics of Tygerberg Hospital, Patients. Twenty-tw o predialysis patients with chronic renal failure were randomly assign ed to a conventional low-protein diet containing 0.6 g protein/kg/d (N = 11), or a very-low-protein diet containing 0.4 g protein/kg/d suppl emented with essential amino acids (N = 11), Nutritional status was as sessed by dietary, anthropometric and biochemical methods at baseline and after 9 months of follow-up, Results. With the exception of energy , there was a significant reduction in the intake of most nutrients on both diets, Protein and phosphorus intake was, however, still above t he recommendations, whereas energy intake generally failed to meet the recommendations. No significant changes were found in the body mass i ndex, arm muscle area, and percentage body fat in any of the groups, a nd the majority of patients fell within normal limits, Very few signif icant changes were observed in biochemical parameters of nutritional s tatus, but plasma amino acid profiles were abnormal in all patients; c holesterol levels were increased in about 50% of patients, the vitamin E/total lipid ratio was increased in almost all patients; and there w as an increase in the percentage of patients with iron deficiency, Fol ate and vitamin B-6 marginal status was common at baseline, but signif icant improvement was demonstrated with supplementation for plasma pyr idoxal-5-P (low-protein diet) and red cell folate (low-protein and ver y-low-protein diet). Conclusion. It is concluded that there was virtua lly no difference between the effects of the low-protein and very-low- protein diets, and that nutritional status was maintained on both diet s during intervention.