Assessment of Zinc Intake From Enriched Water and Other Dietary Sources in Kisumu, Kenya

Introduction: The prevalence of low serum zinc in children under 5 in East Seme, Kisumu is 73.5% and this is likely due at least in part to low bioavailable zinc from the local cereal-based diet. Interventions that will increase zinc intake could prove useful in the effort to control zinc deficiency. A potential strategy is to increase zinc intake through enriched or fortified water. The Life Straw Family filter (LSF, Verstergaard Frandsen S.A, Switzerland) is capable of purifying water and at the same time enriching it with zinc at a variable concentration with mean delivery of approximately 1-4mg/L.

Aims of the study: The primary aim of this study will be to quantify in under 5 year old children the contribution of the household LSF device to zinc intake and dietary zinc bioavailability in participating households. Secondary objectives are; 1) to assess change in serum zinc levels, growth, morbidity in the intervention group compared to control; 2) to characterize composition of the intestinal flora of children in the intervention group compared to control.

Study Design and Methods:

Consenting households from East Seme, Kisumu, Kenya will be randomly allocated to 2 treatment arms in an effectiveness study (90 under-five's per treatment arm). Group one will receive the LSF device with the zinc delivery system; group 2 will receive a LSF without the zinc delivery system.

Zinc intake will be assessed in a subsample of the under 5 year old children enrolled in the effectiveness trial (n=100). This will be estimated by 24 hr recalls administered on 2 non-consecutive days in the dry and wet season. Selected food samples will be collected for direct analysis of zinc and phytic acid content, to supplement data from food composition tables (FCT's). The dietary assessment data will be used to estimate the distribution of zinc intakes in this age group and the EAR cut-off method will be used to estimate the proportion at risk of inadequate intakes.

Data on water intake from the LSF device will be obtained by personal diaries and tally counters. The Zn concentration of the filtered water will be measured weekly. Using these data and the data from the dietary assessment, the contribution of the LSF zinc delivery to the overall dietary zinc intake will be estimated.

The effectiveness study will be conducted as a 6-month double blind randomised trial with 3 assessment time points (baseline, midpoint and endpoint). Three ml (3ml) whole blood will be collected from under 5 year old children enrolled in the households for determination of serum zinc (SZn), C-reactive protein (CRP), Alpha-1- acid glycoprotein (AGP) and hemoglobin (Hb). Stool samples will be collected from a subsample at baseline, midpoint and endpoint in the intervention and control group to assess the composition of the gut microflora and gut inflammation. Anthropometrics (weight and height) will be measured at baseline, midpoint and endpoint of the study. Weekly active surveillance for incidence and severity of malaria, diarrhea and other infectious diseases will be done by questionnaire.