What does vitamin A do?

Question from Ellie Stephens

Vitamin A forms part of the light-sensing pigment rhodopsin, which enables us to see in dim light. It also helps to maintain the immune system, the skin and the membranes that line the nose, mouth and digestive system. Vitamin A deficiency can cause blindness, increased risk of infection and dry, scaly skin, but too much can be dangerous too. In 1913, an Antarctic explorer lost his life after accidentally overdosing on vitamin A by eating dog’s liver.

Answered by Laura Mears for Brain Dump in How It Works issue 117

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