It may spend less time in news headlines than Ebola or the Zika virus, but Vitamin A deficiency is a much bigger public health problem in sub-Saharan Africa and far deadlier.
Estimates say that it affects as many as 43 million children across the continent.
Children affected by the condition are more likely to go blind, have their growth stunted, contract diseases and die earlier.
But now scientists think they may have found an ally in the battle against malnutrition, in the form of that popular African staple, the sweet potato.