Efficacy of Yellow Cassava to Improve Vitamin A Status of Kenyan School Children
Condition: Vitamin A Deficiency
MeSH terms: Night Blindness; Vitamin A Deficiency
Study type: Interventional

Summary: 
      The overall aim of the project is to provide proof-of-principle that biofortification of
      cassava with vitamin A is a viable strategy to improve vitamin A status of deficient
      populations.
    

Detailed description: 
      Rationale: Vitamin A deficiency is still common in developing countries and has been proven
      difficult to combat. A promising approach is to replace common crops with varieties that are
      naturally richer in vitamin A, which is referred to as biofortification. For cassava, yellow
      β-carotene rich varieties have recently been introduced in Kenya, and these varieties are now
      ready to be tested for their efficacy to improve vitamin A status in humans.

      Objective: The primary objective is to measure the effect of daily consumption of provitamin
      A biofortified cassava (providing 50% of the age-specific RDA) on vitamin A status in
      children aged 5-13 years with mild to moderate vitamin A deficiency in Kenya. To determine
      the bioefficacy of provitamin A carotenoids from biofortified cassava relative to that of a
      daily B-carotene supplement (comparison with positive control group). Secondary objectives
      are: 1) to measure the effect of the intervention on immune function indicators and
      morbidity; 2) to determine to what degree the serum retinol response to the intervention
      depends on serum concentrations of retinol and zinc at baseline; 3) to determine the effect
      of the intervention on functional indicators such as dark adaptation capacity, gut integrity,
      hematology indicators and thyroid status; 4) to determine the mediating effect of SNP's in
      the BCMO1 gene on treatment outcome.

      Study design & Study population : In this randomized controlled trial, school children aged
      5-13 years living in the Kibwezi area, Kenya. Children will be selected from three (or four)
      primary schools in the area that have been pre-selected based on the prevalence of vitamin A
      deficiency, location and willingness to participate.

      Intervention: After screening for eligibility and a 2-week run-in period (n=360) Children
      will be randomly allocated to three different treatments: 1) 400 g of yellow cassava
      providing ~50% of the RDA for vitamin A; and a placebo capsule; 2) 400 g of white cassava;
      and a placebo capsule; 3) 400 g of white cassava and a capsule containing 100 RAE of
      all-trans β-carotene.

      Main study parameters/endpoints: The main outcome measure will be differences in serum
      retinol concentrations between groups. Other outcome measures include other vitamin A status
      indicators (β-carotene, retinol binding protein, transthyretin), immune function indicators,
      dark adaptation, iron status indicators, anthropometrics, gut integrity, and thyroid
      function.
    

Intervention name(s): Yellow cassava; White cassava; White cassava
Intervention type(s): Other; Other; Other
Intervention description(s): Daily provision of 375 g boiled yellow cassava for 18 weeks, 6 days/week Daily provision of placebo capsule for 18 weeks, 6 days/week; Daily provision of 375 g boiled white cassava for 18 weeks, 6 days/ week Daily provision of placebo capsule for 18 weeks, 6 days/ week; Daily provision of 375 g boiled white cassava for 18 weeks, 6 days/week Daily provision of B-carotene capsule (1400 µg B-carotene)
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Vitamin A deficiency; Biofortification; Cassava; B-carotene; School children; Kenya