March 1998, Volume 52, Issue 3, Pages 223 – 227

Zinc supplementation, mental development and behaviour in low birth weight term infants in northeast Brazil A Ashworth1,6, SS Morris2,3, PIC Lira1,4 & SM Grantham-McGregor5 1Centre for Human Nutrition, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT     2Maternal and Child Epidemiology Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT     3International Food Policy Research Institute, Washington DC     4Department of Nutrition, Centre for Health Sciences, Federal University of Pernambuco, Recife-PE, Brazil     5Centre for International Child Health, Institute of Child Health, 30 Guilford Street, London WC1N 1EH     6Correspondence: Dr A Ashworth

Keywords

zinc supplementation;   infant development;   behaviour;   low birth weight

Abstract

Objective: To test whether zinc supplementation reduces the deficits in mental development and behaviour that are found in term infants of low birth weight in the study population. Design: A prospective double-blind, part-randomised efficacy trial. Setting: A low-income population in Pernambuco, northeast Brazil, where the economy is largely dependent on sugar-cane production, and where over 90% of deliveries occur in health facilities. Subjects: During a 20-month period, all singleton, term infants weighing 1500-2499 g born to families of low income (<US $280/month) were enroled at birth (n=205). At 6 and 12-months, the numbers tested were 163 and 138 respectively. Intervention: Infants born from January 1993-January 1994 were randomly assigned to receive daily, except Sundays, a placebo (n=66) or 1 mg zinc (n=68). Those born February-August 1994 were given 5 mg zinc (n=71). Supplementation was for eight weeks, starting at birth. Field workers visited each infant at home to administer the supplement. Results: At 6 and 12-months, mental and psychomotor development was assessed with the Bayley Scales of Infant Development and no significant differences in the scores of the three groups were found. At 12-months, behaviour was also assessed on 5 ratings. Ratings were highest in infants given 5 mg zinc (P=0.042). Conclusions: Zinc supplementation (5 mg/d) for eight weeks may reverse some of the poor behaviours, particularly responsiveness, exhibited by low birth weight infants. No amelioration of their mental and psychomotor deficits was found. Sponsorship: The Wellcome Trust, United Kingdom, provided financial support (Grant no. 036605/Z/92). Dr Lira was supported by CAPES (Fundação Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), Brazil.

Received 26 October 1997; Accepted 9 December 1997

^© Macmillan Publishers Ltd 1997