Zn deficiency and diarrhoea are prevalent and may coexist in children living in low-resource settings. Recently, a novel approach for delivering Zn via microbiologically treated, Zn-fortified water was shown to be effective in improving Zn status in West African schoolchildren. We assessed the effectiveness of Zn-fortified, microbiologically purified water delivered as a household intervention on Zn intake, status and morbidity in children aged 2–6 years from rural western Kenya.

Randomised controlled trial. Intervention included households assigned to water treatment device with (ZFW) or without (FW) Zn delivery capability

Rural households in Kisumu, western Kenya.

Children aged 2–6 years.

The ZFW group had higher dietary Zn intake compared with the FW group. ZFW contributed 36 and 31 % of daily requirements for absorbable Zn in children aged 2–3 and 4–6 years, respectively, in the ZFW group. Consumption of Zn-fortified water resulted in lower prevalence of reported illness (risk ratio; 95 % CI) in the ZFW group compared with the FW group: for cold with runny nose (0·91; 0·83, 0·99; P=0·034) and abdominal pain (0·70; 0·56, 0·89; P=0·003) in the intention-to-treat analysis and for diarrhoea (0·72; 0·53, 0·96; P=0·025) in the per-protocol analysis. We did not detect an effect of treatment on plasma Zn concentration.

Daily consumption of Zn-fortified, microbiologically treated water results in increased intake of absorbable dietary Zn and may help in preventing childhood infections in pre-school children in rural Africa.