Efficacy of Yellow Cassava to Improve Vitamin A Status of Kenyan School Children

Not Applicable

Completed

• Conditions: Vitamin A Deficiency
• Interventions: Other: White cassava; Other: Yellow cassava

• Registration Number: NCT01614483
• Lead Sponsor: Wageningen University

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 Timeline

• Study Start: 2012-05
• Study First Submitted: 2012-06-01
• Study First Submitted QC: 2012-06-05
• Study First Posted: 2012-06-08
• Primary Completion: 2012-11
• Study Completion: 2012-11
• Status Verified: 2022-11
• Last Update Submitted: 2022-11-16
• Last Update Posted: 2022-11-21

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 341

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
White cassava + B-carotene capsule	White cassava	-
Yellow cassava + placebo capsule	Yellow cassava	-
White cassava + placebo capsule	White cassava	-

Primary Outcome Measures

Name	Time	Method
Change in serum retinol concentration	Baseline, end of study (4 months)

Secondary Outcome Measures

Name	Time	Method
Thyroid function	End of study (4 months	Serum Tg, TSH
Effect modification	Baseline	Serum zinc, serum retinol, iron status, polymorphisms
Bioefficacy	Baseline, end of study (4 months)	Comparison of change in serum retinol between yellow cassava group and positive control (B-carotene supplement group)
Immune function indicators	End of study (4 months)	neopterin, IL-2, IL4, IL10, IL13, TNF-a, IFN-γ, TGF-β in serum; IgA in saliva
Functional indicators	End of study (4 months)	Gut integrity, dark adaptation, morbidity
Anemia	End of study (4 months)	Hemoglobin

Trial Locations

Locations (1)

Kibwezi District; 🇰🇪 Kibwezi, Eastern Kenya, Kenya