In Zimbabwe, Vitamin A deficiency (VAD) is prevalent where
the impacts of VAD include growth retardation in children and night blindness.
Vitamin A, which is found in some animals and plants, are essential for
vision, growth, cellular differentiation and proliferation, reproduction, and
the maintenance of the immune system.
Like most sub-Saharan African countries, there is a high
maize per capita consumption as maize is an important staple food crop for the
Zimbabweans. For decades, yellow maize has always been the main source of
provitamin A (e.g. β-carotene inclusive) for farm animals that rely on winter-feed rations. Thus,
Zimbabweans usually consume white maize (which has little or no carotenoid
content) as they believe that the yellow maize is supposedly used for the
livestock feed.
Recently, plant scientists have been trying to address the
issue of VAD by increasing the provitamin A concentrations of yellow maize. Plant
food cultivars were cross-bred with the locally cultivated varieties of the
same food to create phenotypes that merge both desirable sets of nutritional
and agronomic characteristics. The people are also being educated about the
benefits of consuming yellow maize through campaigns. The price of the yellow maize
was even made lower than white maize to encourage yellow maize consumption.
However there has been no study about the bioconversion
efficiency of β-carotene to retinol directly in humans…
Until…
......
A study was
conducted among eight healthy Zimbabwean men to evaluate the vitamin A
bioavailability from a yellow maize cultivar bred for its high β-carotene
content.
A selected high β-carotene-containing maize line was
intrinsically labeled with deuterium [2H] (a non-radioactive stable
isotope of hydrogen) to determine
the bioconversion efficiency. On the other hand, a known amount of [13C10]
retinyl acetate in corn oil was used as a reference dose to assess the conversion efficiency of the
maize β-carotene to retinol.
