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Provitamin A–biofortified maize increases serum β-carotene, but not retinol, in marginally nourished children: a cluster-randomized trial in rural Zambia

2016; Elsevier BV; Volume: 104; Issue: 1 Linguagem: Inglês

10.3945/ajcn.116.132571

1938-3207

Amanda Palmer, Ward Siamusantu, Justin Chileshe, Kerry Schulze, Maxwell A. Barffour, Neal E. Craft, Ngosa Molobeka, Ng’andwe Kalungwana, Margia Arguello, Maithilee Mitra, Bess L. Caswell, Rolf Klemm, Keith P. West,

Antioxidant Activity and Oxidative Stress

Background: Vitamin A deficiency remains a nutritional concern in sub-Saharan Africa. Conventionally bred maize hybrids with high provitamin A carotenoid concentrations may have the potential to improve vitamin A status in maize-consuming populations. Objective: We evaluated the efficacy of regular provitamin A carotenoid–biofortified "orange" maizemeal (∼15 μg β-carotene/g) consumption in improving vitamin A status and reducing vitamin A deficiency in children. Design: This was a cluster-randomized controlled trial in the rural farming district of Mkushi, Zambia. All 4- to 8-y-old children in an ∼400-km2 area were identified and grouped by proximity into clusters of ∼15–25 children. We randomly assigned clusters to 1) orange maizemeal (n = 25), 2) white maizemeal (n = 25), or 3) a parallel, nonintervention group (n = 14). Children in intervention clusters (n = 1024) received 200 g maizemeal for 6 d/wk over 6 mo; the maizemeal was prepared according to standardized recipes and served in cluster-level kitchens. Staff recorded attendance and leftovers. We collected venous blood before and after the intervention to measure serum retinol, β-carotene, C-reactive protein, and α1-acid glycoprotein. Results: Intervention groups were comparable at baseline, and vitamin A status was better than anticipated (12.1% deficient on the basis of serum retinol <0.7 μmol/L). Although attendance at meals did not differ (85%), median daily maize intake was higher in white (154 g/d) than in orange (142 g/d) maizemeal clusters. At follow-up, mean serum β-carotene was 0.14 μmol/L (95% CI: 0.09, 0.20 μmol/L) higher in orange maizemeal clusters (P < 0.001), but mean serum retinol (1.00 ± 0.33 μmol/L overall) and deficiency prevalence (17.1% overall) did not differ between arms. Conclusion: In this marginally nourished population, regular biofortified maizemeal consumption increased serum β-carotene concentrations but did not improve serum retinol. This trial was registered at clinicaltrials.gov as NCT01695148.