Provitamin A carotenoid–biofortified maize consumption increases pupillary responsiveness
This article in The Journal of Nutrition elaborates on the effects of pro-vitamin A maize on the visual functions in children in Zambia. With a randomized research trial the researchers found that children who ate “orange maize” showed improved night vision within six months. Their eyes adapted better in the dark, improving their ability to engage in optical day-to-day activities under dim light. Impairment of the eyes’ ability to adapt to low-light conditions is one of the few measurable signs of vitamin A deficiency at its initial stages. In this study scientists used specialized portable equipment to confirm the benefit of eating vitamin A-rich orange maize in a population with marginal deficiency. This new device, called a Portable Field Dark Adaptometer, is a set of goggles manufactured with a digital camera and flash inside. The goggles are connected to a desktop or laptop computer, which can accurately record the response of the pupil in each eye to changing light conditions. The Johns Hopkins team is the first to use this device on a large scale. The bio-fortified orange maize used in this study was conventionally bred to have higher levels of beta-carotene, a naturally occurring plant pigment that the body converts into vitamin A with higher efficiency as the body stores of the vitamin decrease.