Title
Provitamin A Carotenoid-Biofortified Maize Consumption Increases Pupillary Responsiveness among Zambian Children in a Randomized Controlled Trial
Abstract
Background: Impaired dark adaptation is an early functional indicator of vitamin A deficiency that may be prevented by regular dietary intake of foods containing provitamin A carotenoids. Objective: We tested the impact of provitamin A carotenoid–biofortified maize consumption (∼15 μg β-carotene/g) on dark adaptation in Zambian children. Methods: We used a cluster-randomized trial of children aged 4–8 y (n = 1024) in Mkushi District, Zambia, and compared the regular consumption (2 meals/d, 6 d/wk for 6 mo) of biofortified orange maize (OM) to white maize (WM). The primary outcome was the serum retinol response. In a random sample (n = 542), we used a digital pupillometer to test pre- and postintervention responses to graded light stimuli (−2.9 to 0.1 log cd/m2) in a dark-adapted state. Results: At baseline, 11.7% of the children had serum retinol <0.7 μmol/L, 14.4% had impaired dark adaptation (pupillary threshold ≥ −1.11 log cd/m2), and 2.3% had night blindness. The mean ± SD pupillary responsiveness to light stimuli was poorer at baseline in the OM group (16.1% ± 6.6%) than the WM group (18.1% ± 6.4%) (P = 0.02) but did not differ at follow-up (OM: 17.6% ± 6.5%; WM: 18.3% ± 6.5%). Among children with serum retinol <1.05 μmol/L at baseline, there was greater improvement in pupillary responsiveness in the OM group (2.2%; 95% CI: 0.1%, 4.3%) than the WM group (0.2%; 95% CI: −1.1%, 1.5%; P = 0.01), but there were no differences in children with adequate baseline status. We found no effect of treatment on pupillary threshold or night blindness. Conclusions: The regular consumption of provitamin A carotenoid–biofortified maize increased pupillary responsiveness among children with marginal or deficient vitamin A status, providing evidence of a functional benefit to consuming this biofortified crop.
Department(s)
Master of Public Health
Document Type
Article
DOI
https://doi.org/10.3945/jn.116.239202
Keywords
vitamin A deficiency, pupillometry, dark adaptation, biofortification, night blindness
Publication Date
2016
Recommended Citation
Palmer, Amanda C., Katherine Healy, Maxwell A. Barffour, Ward Siamusantu, Justin Chileshe, Kerry J. Schulze, Keith P. West Jr, and Alain B. Labrique. "Provitamin a carotenoid–biofortified maize consumption increases pupillary responsiveness among zambian children in a randomized controlled trial." The Journal of nutrition 146, no. 12 (2016): 2551-2558.
Journal Title
The Journal of nutrition 146
