Effectiveness of zinc-fortified water on zinc intake, status and morbidity in Kenyan pre-school children: a randomised controlled trial

Abstract

Objective: 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.

Design: Randomised controlled trial. Intervention included households assigned to water treatment device with (ZFW) or without (FW) Zn delivery capability SETTING: Rural households in Kisumu, western Kenya.

Subjects: Children aged 2-6 years.

Results: 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.

Conclusions: 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.

Trial registration: ClinicalTrials.gov NCT02162238.

Keywords: Morbidity; Plasma zinc concentration; Pre-school children; Water fortification; Zinc.

Fig. 1

Trial profile (ZFW, zinc-fortified filtered water; FW, filtered water; PZn, plasma zinc)

Fig. 2

Filtered water intake (a, b) and filter usage (c, d) over the study period, by treatment group (a and c, FW group; b and d, ZFW group), among children aged 2–6 years, rural western Kenya, February–August 2014. Solid line represents the median and the shaded area represents the interquartile range (FW, filtered water; ZFW, zinc-fortified filtered water)

Fig. 3

Box-and-whisker plots of water zinc concentrations in samples collected in the households of the two treatment groups at four time points over the 6-month intervention period (n _total 150), rural western Kenya, February–August 2014. The bottom and top edge of the box represent the first and third quartiles (interquartile range); the line within the box represents the median; the ends of the bottom and top whiskers represent the minimum and maximum values; and the average value is marked with +. There was a significant difference in zinc concentrations between intervention (ZFW) and control households (FW; Mann–Whitney U test, P<0·05). (FW, filtered water; ZFW, zinc-fortified filtered water)