Eat Carrots And See Well

New Zealand Listener, Volume 4, Issue 101, 30 May 1941, Page 5

Eat Carrots And See Well

SHORT time ago, the newspapers reported that when one of the pilots of Britain’s night-fighters was being congratulated and questioned about shooting down his second enemy bomber, he explained that he kept himself fit and ate plenty of carrots, because carrots were good for the eyesight. I suppose that quite a number of you also noticed this item, and it is a scientific fact that carrots in the diet help to give clear sight at night. How this has been proved makes quite an interesting story. Investigators had found that a deficiency of Vitamin A resulted in xerophthalmis, an eye disease which would result in blindness if the deficiency were sufficiently acute and prolonged, They set out to find which were the foods which would give enough of the vitamin to sustain the greatest rate of growth, and to protect the mucus membranes and especially the eyes from’ disease, Further work showed that although not Vitamin A itself, carotene is the substance from which our bodies as well as those of animals and fish, are able to manufacture the vitamin. Thus when we eat cabbage, care rots, yellow pumpkin, tomatoes, etc., we take in a stock of carotene which the body, by a chemical process, converts into Vitamin A, to be used in the body, or stored in the liver according to our bodily needs. To understand how this is related to night sight cne has to know something about the eye and what inskes the eye able to transmit sensations of colour and of light to the optic nerve and so to the brain. This is done by virtue of millions of incredibly fine colour and light receivers, which form the inner skin or retina or the eye ball. These light receivers contain a substance known as visual purple, which, like an unexposed camera plate or film, can be chunged by the action of light. When light shines into the eye, the visual purple is bleached, and the ability of our eyes to adapt themselves to see in darkness after light, depends on their ability to manufacture visual purple, and the more visual purple there is in the sensitive retina of the eye, the better it can see whatever light there may be even on the darkest night. Now it only remains for me to tell you that visual purple and Vitamin A are practically the same chemically, and that the visual purple is made from the Vitamin A brought in by the blood, and you will at once see the connection between carrots, or liver and night sight-(A.C.E. Talk, "Diet and Clear Sight," 4YA, May 14).