Impact of zinc supplementation on persistent diarrhoea in malnourished Bangladeshi children SK Roy 1 , AM Tomkins 2 , D Mahalanabis 1 , SM Akramuzzaman 1 , R Haider 1 , RH Behrens 3 and G Fuchs 1 Clinical Sciences Division 1 , International Centre for Diarrhoeal Diseases Research, Dhaka, Bangladesh; Centre for International Child Health 2 , Institute of Child Health, London, UK; Clinical Nutrition Unit 3 , Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, London, UK Roy SK, Tomkins AM, Mahalanabis D, Akramuzzaman SM, Haider R, Behrens RH, Fuchs G. Impact of zinc supplementation on persistent diarrhoea in malnourished Bangladeshi children. Acta Pædiatr 1998; 87: 1235–9. Stockholm. ISSN 0803-5253 To evaluate the impact of zinc supplementation on the clinical recovery and body weight of children with persistent diarrhoea, a randomized, double-blind, controlled trial was conducted in 190 children with persistent diarrhoea aged between 3 and 24 months. Children were randomly allocated to receive either zinc (20 mg d -1 ) syrup with multivitamin (2 × RDA) or multivitamin alone in three divided daily doses for 2 weeks. The trial was conducted in a diarrhoeal disease hospital in Dhaka, Bangladesh. Duration until clinical recovery (d), impact on body weight and serum zinc level after 2 weeks of zinc supplementation were recorded. The duration of illness was significantly reduced (33%) with zinc supplementation among children who were underweight (70% wt/age, p ¼ 0:03). Supplemented male children also had a significant reduction (27%) in duration for recovery compared with unsupplemented children (p ¼ 0:05). From baseline to convalescence, zinc-supplemented children maintained their serum zinc concentration (13.4 vs 13.6 mmol l -1 ), whereas unsupplemented children had a decrease in serum zinc after the 2 weeks of diarrhoea (13.6 vs 11.8 mmol l -1 , p  0:03). The mean body weight of the children in the supplemented group was maintained (5.72 vs 5.70 kg, p ¼ 0:62) during hospitalization, unlike that of the control group, in which there was a reduction in body weight (5.75 vs 5.67 kg, p ¼ 0:05). Five children in the unsupplemented group and one child in the zinc-supplemented group died during the 2 weeks of supplementation ( p ¼ 0:06). Zinc supplementation in persistent diarrhoea significantly reduced the length of the recovery period in mal- nourished children and prevented a fall in body weight and serum zinc concentration, indicating that zinc is a beneficial therapeutic strategy in this high-risk childhood illness.  Children, malnutrition, persistent diarrhoea, recovery, weight loss, zinc SK Roy, ICDDR,B, Dhaka, GPO Box 128, Bangladesh Diarrhoea remains a major cause of morbidity and mortal- ity in less developed countries (LDC) (1). A significant proportion of children who suffer from diarrhoea are malnourished and this may contribute to the increased severity and duration of diarrhoea in such children (2–4). In Bangladesh, malnutrition is associated with an increased prevalence of persistent diarrhoea (5) and about 9% of acute diarrhoeal episodes become persistent (6). Children are at risk of zinc depletion during and after episodes of diarrhoeal disease, which is largely explained by excess faecal losses, of up to 300 mg of zinc kg body weight -1 d -1 , in children with persistent diarrhoea (7). Zinc deficiency is associated with impaired immunity, growth retardation and hypogeusia (8). Zinc improves intestinal mucosal integrity as well as absorption of water and electrolytes in experimental studies (9, 10) and has been shown to improve weight gain in severely malnourished Banglade- shi (11) and Jamaican children (12). Zinc supplementation also reduced the net secretion of water and electrolytes induced by cholera toxin in experimental zinc deficiency (13). The current study studied the hypothesis that zinc deficiency is present in malnourished children with persis- tent diarrhoea and that zinc supplementation would reduce the duration of persistent diarrhoea in malnourished children. Subjects and methods A double-blind, randomized, controlled clinical trial was conducted at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). Children were consid- ered to be eligible for the study if they presented with the persistent diarrhoea syndrome (PDS), defined as diarrhoea for more than 14 d duration. Ninety-five children between 3 and 24 months of age were randomly assigned to each group using a block randomization procedure (14) in which blocks of 8 patients were equally allocated to either the treatment or the control group. Sample size was calculated on the assumption that zinc supplementation would reduce the duration of diarrhoea by 20%, taking probability at the 5% level and power at 80%, according to the formula Acta Pædiatr 87: 1235–9. 1998  Scandinavian University Press 1998. ISSN 0803-5253