For most clinicians, vitamin A is first and foremost associated with eye disease. Vitamin A deficiency causes a range of ocular manifestations including xerophthalmia, night blindness, Bitot’s spots, and keratomalacia. Indeed, vitamin A and the eye provide a well known example of the importance of micronutrients for health, and many children have been told to eat their carrots because it is good for their eyes. In the linked long term follow-up of a randomised controlled trial, Schmitz and colleagues (doi:10.1136/bmj.d7962) assess a different effect of vitamin A—whether vitamin A supplementation in the preschool years can reduce hearing loss.1

Vitamin A has many important functions in the human body and its role in resistance to infectious diseases has been known for almost 100 years.2 However, interest in vitamin A waned with the appearance of antibiotics, to return in the 1980s when a study in Indonesia showed that half yearly high dose vitamin A supplementation dramatically reduced child mortality.3 This brought vitamin A …