title: Biofortified yellow cassava and vitamin A status of Kenyan children: a randomized controlled trial.
abstract: BACKGROUND
  Whereas conventional white cassava roots are devoid of provitamin A, biofortified yellow varieties are naturally rich in β-carotene, the primary provitamin A carotenoid.
  
  
  OBJECTIVE
  We assessed the effect of consuming yellow cassava on serum retinol concentration in Kenyan schoolchildren with marginal vitamin A status.
  
  
  METHODS
  We randomly allocated 342 children aged 5-13 y to receive daily, 6 d/wk, for 18.5 wk 1) white cassava and placebo supplement (control group), 2) provitamin A-rich cassava (mean content: 1460 μg β-carotene/d) and placebo supplement (yellow cassava group), and 3) white cassava and β-carotene supplement (1053 μg/d; β-carotene supplement group). The primary outcome was serum retinol concentration; prespecified secondary outcomes were hemoglobin concentration and serum concentrations of β-carotene, retinol-binding protein, and prealbumin. Groups were compared by using ANCOVA, adjusting for inflammation, baseline serum concentrations of retinol and β-carotene, and stratified design.
  
  
  RESULTS
  The baseline prevalence of serum retinol concentration <0.7 μmol/L and inflammation was 27% and 24%, respectively. For children in the control, yellow cassava, and β-carotene supplement groups, the mean daily intake of cassava was 378, 371, and 378 g, respectively, and the total daily supply of provitamin A and vitamin A from diet and supplements was equivalent to 22, 220, and 175 μg retinol, respectively. Both yellow cassava and β-carotene supplementation increased serum retinol concentration by 0.04 μmol/L (95% CI: 0.00, 0.07 μmol/L); correspondingly, serum β-carotene concentration increased by 524% (448%, 608%) and 166% (134%, 202%). We found no effect on hemoglobin concentration or serum concentrations of retinol-binding protein and prealbumin.
  
  
  CONCLUSIONS
  In our study population, consumption of yellow cassava led to modest gains in serum retinol concentration and a large increase in β-carotene concentration. It can be an efficacious, new approach to improve vitamin A status. This study was registered with clinicaltrials.gov as NCT01614483.
authors.affiliation: Division of Human Nutrition and elise.talsma@gmail.com.
authors.forename: Elise F
authors.identifier: http://orcid.org/0000-0002-6034-4708
authors.initials: EF
authors.lastname: Talsma
authors.affiliation: Division of Human Nutrition and.
authors.forename: Inge D
authors.identifier: http://orcid.org/0000-0002-9346-9689
authors.initials: ID
authors.lastname: Brouwer
authors.affiliation: Cell Biology and Immunology Group, Wageningen University, Wageningen, Netherlands; Medical Research Council (MRC) International Nutrition Group, London School of Hygiene & Tropical Medicine, London, United Kingdom, and MRC Keneba, The Gambia;
authors.forename: Hans
authors.initials: H
authors.lastname: Verhoef
authors.affiliation: Applied Nutrition Program, Department of Food Technology and Nutrition, University of Nairobi, Nairobi, Kenya;
authors.forename: Gloria N K
authors.initials: GN
authors.lastname: Mbera
authors.affiliation: Applied Nutrition Program, Department of Food Technology and Nutrition, University of Nairobi, Nairobi, Kenya;
authors.forename: Alice M
authors.initials: AM
authors.lastname: Mwangi
authors.affiliation: Laboratory for Clinical Chemistry, Meander Medical Centre, Amersfoort, Netherlands;
authors.forename: Ayşe Y
authors.initials: AY
authors.lastname: Demir
authors.affiliation: International Institute of Tropical Agriculture, Ibadan, Nigeria;
authors.forename: Busie
authors.initials: B
authors.lastname: Maziya-Dixon
authors.affiliation: HarvestPlus, International Food Policy Research Institute, Washington, DC; and.
authors.forename: Erick
authors.identifier: http://orcid.org/0000-0002-0271-1725
authors.initials: E
authors.lastname: Boy
authors.affiliation: Human Nutrition Laboratory, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, Swiss Federal Institute of Technology, Zürich, Switzerland.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Zimmermann
authors.affiliation: Division of Human Nutrition and.
authors.forename: Alida
authors.identifier: http://orcid.org/0000-0001-8406-7592
authors.initials: A
authors.lastname: Melse-Boonstra
mesh_terms: D000704:Analysis of Variance; D002648:Child; D004032:Diet; D019587:Dietary Supplements; D002149:Energy Intake; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007249:Inflammation / Q000453:epidemiology; D007630:Kenya / Q000453:epidemiology; D008297:Male; D002365:Manihot / Q000737:chemistry; D009752:Nutritional Status; D018517:Plant Roots / Q000737:chemistry; D015995:Prevalence; D014675:Vegetables / Q000737:chemistry; D014801:Vitamin A / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D014802:Vitamin A Deficiency / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology; D019207:beta Carotene / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D019207:beta Carotene; D014801:Vitamin A
keywords: biofortification; efficacy; food-based approach; nutrition-sensitive intervention; vitamin A