Oral zinc for treating diarrhoea in children
Marzia Lazzerini, Humphrey Wanzira
Institute for Maternal and Child Health IRCCS Burlo Garofolo, WHO Collaborating Centre for Maternal and Child Health, Trieste, Italy
Lazzerini M, Wanzira H. Oral zinc for treating diarrhoea in children. Cochrane Database of Systematic Reviews 2016, Issue 12. Art. No.: CD005436. DOI: 10.1002/14651858.CD005436.pub5.
Access the full-text article here: http://onlinelibrary.wiley.com/wol1/doi/10.1002/14651858.CD005436.pub5/full
Oral zinc supplementation for treating diarrhoea in children
In low- and middle-income countries, millions of children suffer from severe diarrhoea every year and many die from dehydration. Giving fluids by mouth (using an oral rehydration solution (ORS)) has been shown to save children's lives, but it has no effect on the length of time the children suffer with diarrhoea. Zinc supplementation could help reduce the duration and the severity of diarrhoea, and therefore have an additional benefit over ORS in reducing children mortality.
What is oral zinc and how may it shorten the duration and severity of diarrhoea
Zinc is usually given as zinc sulphate, zinc acetate, or zinc gluconate, which are all water-soluble compounds. The World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) recommend 10 mg to 20 mg of zinc per day for children with diarrhoea. There are several mechanism of action of zinc on acute diarrhoea, some of which are specific to the gastrointestinal system: zinc restores mucosal barrier integrity and enterocyte brush-border enzyme activity, it promotes the production of antibodies and circulating lymphocytes against intestinal pathogens, and has a direct effect on ion channels, acting as a potassium channel blocker of adenosine 3-5-cyclic monophosphate-mediated chlorine secretion. Cochrane researchers examined the evidence available up to 30 September 2016.
What the evidence in the review suggests
Thirty-three trials that included 10,841 children met the inclusion criteria of this review.
Among children with acute diarrhoea, we don't know if treating children with zinc has an effect on death or number of children hospitalized (very low certainty evidence). In children older than six months, zinc supplementation may shorten the average duration of diarrhoea by around half a day (low certainty evidence), and probably reduces the number of children whose diarrhoea persists until day seven (moderate certainty evidence). In children with signs of malnutrition the effect appears greater, reducing the duration of diarrhoea by around a day (high certainty evidence). Conversely, in children younger than six months, the available evidence suggests zinc supplementation may have no effect on the mean duration of diarrhoea (moderate certainty evidence), or the number of children who still have diarrhoea on day seven (moderate certainty evidence). Zinc supplementation increased the risk of vomiting in both age groups (moderate certainty evidence). No other adverse effects were reported.
Among children with persistent diarrhoea, zinc supplementation probably shortens the average duration of diarrhoea by around 16 hours (moderate certainty) but it probably increases the risk of vomiting (moderate certainty evidence).
In areas where the prevalence of zinc deficiency or the prevalence of malnutrition is high, zinc may be of benefit in children aged six months or more. The current evidence does not support the use of zinc supplementation in children less six months of age, in well-nourished children, and in settings where children are at low risk of zinc deficiency.