Efficacy of Yellow Cassava to Improve Vitamin A Status of Mildly Deficient Primary School Children in Kenya: a Randomized Controlled Trial
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Wageningen University
- Enrollment
- 341
- Locations
- 1
- Primary Endpoint
- Change in serum retinol concentration
Study Overview
Brief 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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Prevention
- Masking
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Eligibility Criteria
- Ages
- 61 Months to 13 Years (Child)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Low vitamin A status (retinol binding protein (RBP) at the lowest end of the distribution will be included in the study)
Exclusion Criteria
- •History or signs of infectious or systemic diseases (e.g. tuberculosis, sickle cell anaemia)
- •Anaemia, malaria or acute inflammation at the day of baseline measurements
Arms & Interventions
White cassava + placebo capsule
Intervention: White cassava (Other)
White cassava + B-carotene capsule
Intervention: White cassava (Other)
Yellow cassava + placebo capsule
Intervention: Yellow cassava (Other)
Outcomes
Primary Outcomes
Change in serum retinol concentration
Time Frame: Baseline, end of study (4 months)
Secondary Outcomes
- Thyroid function(End of study (4 months)
- Effect modification(Baseline)
- Bioefficacy(Baseline, end of study (4 months))
- Immune function indicators(End of study (4 months))
- Functional indicators(End of study (4 months))
- Anemia(End of study (4 months))
Investigators
Alida Melse
PhD
Wageningen University