Clinical trial NCT01614483: Efficacy of Yellow Cassava to Improve Vitamin A Status of Kenyan School Children
Official title: Efficacy of Yellow Cassava to Improve Vitamin A Status of Mildly Deficient Primary School Children in Kenya: a Randomized Controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Vitamin A Deficiency
Keywords: Vitamin A deficiency
Biofortification
Cassava
B-carotene
School children
Kenya
Lead sponsor: Wageningen University
Sponsor class: OTHER
Collaborators: name: European Commission
name: University of Nairobi
First posted: 2012-06-08
Enrollment: 341
Sex: ALL
Minimum age (years): 61
Maximum age (years): 13
Standard ages: CHILD
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

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.

Eligibility criteria: 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

Primary outcomes:
measure: Change in serum retinol concentration
timeFrame: Baseline, end of study (4 months)
Secondary outcomes:
measure: Immune function indicators
timeFrame: End of study (4 months)
measure: Bioefficacy
timeFrame: Baseline, end of study (4 months)
measure: Functional indicators
timeFrame: End of study (4 months)
measure: Thyroid function
timeFrame: End of study (4 months
measure: Effect modification
timeFrame: Baseline
measure: Anemia
timeFrame: End of study (4 months)
Other outcomes:
Locations:
city: Kibwezi
country: Kenya
facility: Kibwezi District
state: Eastern Kenya
Study officials:
affiliation: Wageningen University
name: Alida Melse, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Talsma EF, Brouwer ID, Verhoef H, Mbera GN, Mwangi AM, Demir AY, Maziya-Dixon B, Boy E, Zimmermann MB, Melse-Boonstra A. Biofortified yellow cassava and vitamin A status of Kenyan children: a randomized controlled trial. Am J Clin Nutr. 2016 Jan;103(1):258-67. doi: 10.3945/ajcn.114.100164. Epub 2015 Dec 16.
citation: Talsma EF, Melse-Boonstra A, de Kok BP, Mbera GN, Mwangi AM, Brouwer ID. Biofortified cassava with pro-vitamin A is sensory and culturally acceptable for consumption by primary school children in Kenya. PLoS One. 2013 Aug 30;8(8):e73433. doi: 10.1371/journal.pone.0073433. eCollection 2013.
citation: Talsma EF, Borgonjen-van den Berg KJ, Melse-Boonstra A, Mayer EV, Verhoef H, Demir AY, Ferguson EL, Kok FJ, Brouwer ID. The potential contribution of yellow cassava to dietary nutrient adequacy of primary-school children in Eastern Kenya; the use of linear programming. Public Health Nutr. 2018 Feb;21(2):365-376. doi: 10.1017/S1368980017002506. Epub 2017 Oct 2.