Efficacy of Yellow Cassava to Improve Vitamin A Status of Kenyan School Children (CASSAVITA)
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.
|Study Design:||Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
|Official Title:||Efficacy of Yellow Cassava to Improve Vitamin A Status of Mildly Deficient Primary School Children in Kenya: a Randomized Controlled Trial|
- Change in serum retinol concentration [ Time Frame: Baseline, end of study (4 months) ] [ Designated as safety issue: No ]
- Immune function indicators [ Time Frame: End of study (4 months) ] [ Designated as safety issue: No ]neopterin, IL-2, IL4, IL10, IL13, TNF-a, IFN-γ, TGF-β in serum; IgA in saliva
- Bioefficacy [ Time Frame: Baseline, end of study (4 months) ] [ Designated as safety issue: No ]Comparison of change in serum retinol between yellow cassava group and positive control (B-carotene supplement group)
- Functional indicators [ Time Frame: End of study (4 months) ] [ Designated as safety issue: No ]Gut integrity, dark adaptation, morbidity
- Thyroid function [ Time Frame: End of study (4 months ] [ Designated as safety issue: No ]Serum Tg, TSH
- Effect modification [ Time Frame: Baseline ] [ Designated as safety issue: No ]Serum zinc, serum retinol, iron status, polymorphisms
- Anemia [ Time Frame: End of study (4 months) ] [ Designated as safety issue: No ]Hemoglobin
|Study Start Date:||May 2012|
|Study Completion Date:||November 2012|
|Primary Completion Date:||November 2012 (Final data collection date for primary outcome measure)|
|Experimental: Yellow cassava + placebo capsule||
Other: Yellow cassava
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
|Placebo Comparator: White cassava + placebo capsule||
Other: White cassava
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
|Active Comparator: White cassava + B-carotene capsule||
Other: White cassava
Daily provision of 375 g boiled white cassava for 18 weeks, 6 days/week Daily provision of B-carotene capsule (1400 µg B-carotene)
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.
|Kibwezi, Eastern Kenya, Kenya|
|Principal Investigator:||Alida Melse, PhD||Wageningen University|