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

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Efficacy of Yellow Cassava to Improve Vitamin A Status of Mildly Deficient Primary School Children in Kenya: a Randomized Controlled Trial

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 Summary:

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
Sponsor: Wageningen University

Current Primary Outcome: Change in serum retinol concentration [ Time Frame: Baseline, end of study (4 months) ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

• Immune function indicators [ Time Frame: End of study (4 months) ]
  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) ]
  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) ]
  Gut integrity, dark adaptation, morbidity
• Thyroid function [ Time Frame: End of study (4 months ]
  Serum Tg, TSH
• Effect modification [ Time Frame: Baseline ]
  Serum zinc, serum retinol, iron status, polymorphisms
• Anemia [ Time Frame: End of study (4 months) ]
  Hemoglobin

Original Secondary Outcome: Same as current

Information By: Wageningen University

Dates:
Date Received: June 1, 2012
Date Started: May 2012
Date Completion:
Last Updated: January 29, 2013
Last Verified: January 2013