Zinc Absorption From Fortified Water
Condition: Fractional Absorption of Zinc (Focus of the Study)
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): LSF water without meal; LSF water and inhibitory meal; Fortified inhibitory meal with water
Intervention type(s): Device; Device; Other
Intervention description(s): Composition of test meal: 67Zn-labelled LSF-fortified water (1 mg 67Zn as ZnSO4 + 1 mg of eluted Zn from LSF device of natural isotopic composition); Composition of test meal: Maize porridge and 67Zn-labelled LSF-fortified water (1 mg 67Zn as ZnSO4 + 0.44 mg of eluted Zn from LSF device of natural isotopic composition); Composition of test meal: Maize porridge (1 mg 67Zn as ZnSO4 + 0.44 mg Zn as ZnSO4 of natural isotopic composition) and high purity water
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: zinc; absorption; bio-availability; aqueous zinc; zinc deficiency; zinc fortification