Question: How do carrots improve your eyesight?

Simon Langley-Evans answered on 18 Nov 2013:

Great question with a lengthy answer.

First of all, it is a myth that carrots improve your eyesight. It is what we would call an old wives tale. But like most of these old wives tales, there is some truth in it.

Aspects of our vision rely on a pigment in the eye called rhodopsin. This pigment is ‘bleached’ by light photons when we perceive light and to keep our vision going we need to have a good supply of vitamin A. Vitamin A comes in two forms. One is made by animals and is called retinol. This is the true vitamin A and is responsible for regenerating rhodopsin that has been bleached. The other form of vitamin A is called beta carotene and comes from plants. When we consume it we convert it into retinol.

If the diet is low in vitamin A our sight is affected in different ways. One of the first signs of a problem is that our eyes become less effective at seeing in dim light and this can become something called light blindness. This is where the old wives tale comes in, because carrots are rich in beta carotene (which is an orange pigment). Consuming lots of carrots would provide lots of vitamin A and keep up our night vision.

I said it was a long answer, and I haven’t finished yet. A lack of vitamin A can have an even worse effect on the eye. Without vitamin A our eyes become very dry and rough and this helps bacteria to infect the eyeball. This can lead to ulcers forming on the eye and even the permanent loss of the eye and full, irreversible blindness.

Vitamin A deficiency is very common around the world and especially affects children under 5 and women who are pregnant. It causes half a million cases of blindness every year across the world.