Micronutrient intake in haemodialysis patients

Abstract

Background: Previous research has shown significantly reduced mortality in haemodialysis (HD) patients supplemented with water‐soluble vitamins (Fissel et al., 2004). HD patients have increased requirements along with altered intake, metabolism and absorption of micronutrients due to the build up of uraemic toxins and the treatment of dialysis, diet and medication. Renal recommended intakes (RRI) acknowledge this increased need (Fouque, 2003). The aim of this study was to establish the adequacy of micronutrient intake in a cohort of HD patients attending Portsmouth dialysis unit.Methods: A random sample (n = 24) of stable HD patients completed 5‐day food diaries, these were analysed for energy, protein and micronutrient intake using Windiets. Descriptive statistics; t‐tests; correlation and regression, as appropriate for data distribution, were performed using SPSS (v14). Individual mean energy and protein intake were compared to requirements (DH, 1991). Micronutrient intakes were compared to the reference nutrient intakes (DH, 1991) and renal recommended intakes (Fouque, 2003). Mean nutrient intake was compared to age; duration on dialysis; gender and marital status (n = 24). Intake on dialysis and non‐dialysis days was compared (n = 7). Ethical approval was applied for with the conclusion this was an audit.Results: Mean protein intake was adequate [71 g day−1 (SD 24)], while energy intake was inadequate [8095 kJ day−1 (SD 2241)].There were no significant relationships between nutrient intake and age, gender or marital status. Those who had been on dialysis longer had significantly reduced intakes of protein, niacin, pyridoxine and selenium (P < 0.05) as shown in Table 1. There was no significant difference between intake on dialysis and non‐dialysis days. Summary of micronutrient intake. Nutrient Mean recorded intake (SD) Number of patients with intake below RNI (%) Number of patients with intake below RRI (%) Thiamin (mg) 1.6 (1.1) 0 (0) 15 (67) Riboflavin (mg) 1.4 (0.6) 7 (29) 20 (83) Niacin (mg) 31.3 (11.0) 0 (0) 3 (13) Biotin (μg) 23.5 (5.7) 0 (0) No RRI Pantothenic acid (mg) 4.3 (2.3) 4 (17) 19 (79) Pyridoxine (mg) 1.5 (0.6) 5 (21) 24 (100) Folate (μg) 205.9 (68.3) 13 (54) 24 (100) Cobalamin (μg) 3.9 (2.1) 2 (8) 8 (33) Vitamin C (mg) 62.7 (57.5) 9 (38) 19 (79) Iron (mg) 10.4 (3.5) 9 (38) 12 (50) Selenium (μg) 66.1 (26.8) 9 (38) No RRI Zinc (mg) 7.7 (3.2) 13 (54) 23 (96) Vitamin E (mg) 5.6 (2.2) 2 (8) 22 (92) Discussion: The intake of many micronutrients in a substantial proportion of patients appeared poor, which may exacerbate relative deficiencies due to altered metabolism. No patients attained the requirements for folate and pyridoxine; recommendations are 400% and 733% above the reference nutrient intake (Fouque, 2003). Patients who have been on dialysis for longer appeared to have poorer intakes of some micronutrients.Conclusions: Micronutrient intake in this sample was poor; requirements appear unachievable by diet alone. Supplementation may be beneficial but further study is required with assessment of blood levels.References Department of Health. (1991) Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. In: Report of the Panel on Dietary Reference Values of the Committee on Medical Aspects of Food Policy (COMA). Report on Health and Social Subjects 41. London: HMSO.Fissel, R.B., Bragg‐Gresham J.L., et al. (2004) International variation in vitamin prescription and association with mortality in the Dialysis Outcomes and Practice Patterns Study (DOPPS). Am. J. Kidney Dis.44, 293–299.Fouque, D. (2003) Nutritional requirements in maintenance haemodialysis. Adv. Ren. Replace. Ther.10, 183–193.