A randomized controlled clinical trial of zinc, vitamin A or both in undernourished children with persistent diarrhea in Bangladesh

In a double-blind randomized controlled clinical trial, moderately malnourished Bangladeshi children (61-75% of the median weight/age) were studied for the effect of zinc and/or vitamin A supplementation on the clinical outcome of persistent diarrhea. Children 6 mo to 2 y of age with diarrhea for more than 14 d were randomly allocated into 4 groups of 24 receiving a multivitamin syrup and (i) zinc (20 mg elemental), (ii) vitamin A, (iii) both zinc and vitamin A, or (iv) neither, in 2 doses daily for 7 d. Clinical data on recovery and on stool output, consistency and frequency were recorded for 7 d, and weight change from day 1 to day 7 was assessed. The baseline characteristics of the four study groups were comparable. The mean daily stool outputs from days 2 to 7 of therapy were significantly less in the zinc and zinc plus vitamin A groups, but not in the vitamin A group, in comparison with the control group. In children receiving zinc, the cumulative stool weight in the 7 d was 39% less than in the control group (p < 0.001) and 32% less than in the vitamin A group (p = 0.006). The cumulative stool weight in the zinc plus vitamin A group was 24% less than in the control group (p < 0.001), but the 14% lower output than in the vitamin A group was not statistically different. The change in body weight over the 7 d study period was significantly different between the group receiving zinc and the control group (+111 g vs -90 g, p = 0.045). The rate of clinical recovery of children within 7 d was significantly greater in the zinc group (88%) compared with the control group (46%, p = 0.002) or vitamin A group (50%, p = 0.005), but not statistically different from the zinc plus vitamin A group (67%, p = 0.086). The results indicate that zinc, but not vitamin A, supplementation in persistent diarrhea reduces stool output, prevents weight loss and promotes earlier recovery.