Fractional Absorption of Zinc (Focus of the Study) Clinical Trial
Official title:
Zinc Absorption From Enriched Drinking Water Compared With the Zinc Absorption From a Fortified Maize Pudding in Healthy Young Adults.
A water purifying system, called LifeStrawFamily (LSF), able to fortify water with zinc to a concentration of 4 mg/l has been developed. The aim of this study is to investigate whether the LSF strategy is advantageous in terms of zinc absorption compared to food fortification. This study wants to demonstrate whether aqueous zinc produced by the LSF device consumed within or outside meals is better absorbed than zinc from an enriched cereal-based staple food in healthy adults. In addition, the zinc absorption from the LSF-enriched water and from a fortified inhibitory cereal-based pudding will be compared.
Zinc bioavailability from a food or diet depends on the content of zinc and the presence of
inhibitors of zinc absorption, e.g. inositol phosphate, also known as phytic acid (PA), and
it is typically estimated with the phytate to zinc molar ratio (Phy:Zn). A zinc absorption
of 10-15% is estimated from diets containing mainly unrefined cereal grains or legumes with
negligible amounts of animal proteins, which are dominant in developing countries
(characterised by a Phy:Zn > 15). For comparison, a mixed animal and plant product diet
(Phy:Zn ranging 5-15) is estimated to have an average zinc bioavailability of 20-30% whereas
a diet with ample refined cereals and rich in animal foods (Phy:Zn < 5) would have average
zinc bioavailability of 30-50% (12, 19). Fractional absorption from aqueous zinc sulphate or
zinc chloride solutions taken in a fasting state has been shown to range 56-74% for doses of
0.5-10 mg zinc (20-24) and decreasing to 37-62% for doses of 13-30.1 mg zinc (22, 24). Zinc
from drinking water consumed away from meals appears to be substantially better absorbed
than that from composite foods. Alternative strategies, designed for providing zinc through
the water supply, could prove useful in the global effort to control zinc deficiency.
To investigate whether zinc eluted from Lifestraw Family® (LSF) device via its specific zinc
delivery system is more bioavailable than zinc from fortified cereals as zinc sulphate, we
will perform a human absorption study based on the double isotopic tracer ratio technique.
The fractional absorption of zinc (FAZ) from LSF-fortified water consumed with or without
food will be compared to the FAZ from a fortified cereal. This will allow quantifying zinc
bioavailability from the LSF eluted zinc 1) when LSF-water is consumed in fasting state 2)
when LSF-water is consumed together with other foods 3) to compare the latter two with zinc
absorption from a zinc fortified cereal.
The results of this study will provide information on the potential advantages of LSF
fortification over zinc food fortification, which is currently the recommended delivery
vehicle for zinc in country fortification programs (25, 26). Furthermore, comparing zinc
bioavailability from LSF-water consumed alone or in combination with food will instruct
about the optimal way to consume it. This information can be used to optimally design the
delivery strategy in the planned efficacy trials. In the future, this information could also
be integrated in the information recommendations for use for prospective end-consumers.
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Allocation: Randomized, Endpoint Classification: Bio-availability Study, Intervention Model: Crossover Assignment, Masking: Open Label, Primary Purpose: Basic Science