At some point while growing up, you have probably been told that eating carrots will make you see in the dark. The theory supposedly goes back to World War 2, when the RAF contributed the accuracy of its fighter pilots to a diet full of carrots. But was this just a ruse to get children to eat there veg or is there genuine scientific evidence to carrots being the superfood that can turn you into the next superhero? The answer is both yes and no. Let me explain.
The important component in carrots that helps the eyes, is beta-carotene which is a precursor (inactive form) to vitamin A. Vitamin A is a fat-soluble vitamin that comes in three different forms; retinal, retinol and retinoic acid and is needed by the retina of the eye in the form of retinal. Retinal is important in vision as it binds to a protein within the eye called opsin. Together they form rhodopsin. Why is rhodopsin important? Well Rhodopsin is a light-sensitive receptor protein, found in the rods of the retina, involved in helping you see. In dim light rods are involved in the visual processes by conveying objects as black-and white images through monochromatic vision. This enables us to distinguish between objects through differing shades, tones and tints of black. So basically you need rhodopsin, and therefore vitamin A, to see, especially in dim light.
Carrots for the elderly!
Vitamin A is particularly important for the elderly as they are the most likely to be deficient due to poor absorption and reduced intake. Some studies have linked vitamin A to delaying cataracts, a condition which causes misty or cloudy vision due to changes in the lens of the eye. It can also help the immune system fight infection and aid the combatting of skin problems.
Dry eyes and prolonged vitamin A deficiency
Whilst night blindness is far from what you want, prolonged Vitamin A deficiency can be even worse and can lead to permanent blindness through a condition known as Xerophthalmia. It sounds a bit complicated but Xerophthalmia is basically dryness of the conjunctiva and cornea, parts of your eyes, that can be brought about by vitamin A deficiency. Although the mechanism is not entirely known, Xerophthalmia is caused by lack of retinoic acid, a metabolite of vitamin A, and thought to be due to retinoic acid aiding good health in epithelial cells, such as those in the cornea. Vitamin A deficiency can increase the vulnerability of the eye to infections and lesions and cause hardening (keratinization) and opacity of the cornea.
Before you get too worried and start eating carrots by the bowlful like a crazed rabbit, vitamin A deficiency in developed countries is rare. So relax! However, if you feel you are struggling more and more to find your way to the bathroom in the middle of the night, you may want to consider adding some more vitamin A to your diet. Increasing your Vitamin A can decrease your chances of dry eyes and delay the onset of cataracts.
How else can you get your Vitamin A?
Not a fan of carrots? Don’t worry you’re not going to be sent down a route of night blindness or hardened corneas. There are plenty of other ways to get your Vitamin A! The NHS website lists cheese, eggs, oily fish, milk, yoghurt and liver products such as liver pâté as good sources of Vitamin A. Don’t worry vegans you haven’t been forgotten! Along with carrots, there are plenty of good meat free vitamin A sources such as butternut squash, sweet potato and green vegetables. However, being a fat-soluble vitamin and therefore harder to excrete Vitamin A toxicity (too high levels) can be a problem. High levels of Vitamin A can increase your risk of osteoporosis, a condition that weakens bones, and can be harmful to your unborn baby if you have high amounts of it during pregnancy. The recommended daily allowance is 0.7mg a day for men and 0.6mg a day for women.
Catar-Act on your lack of Vitamin A
Disappointingly carrots will not give you superpowers making you able to see in complete darkness so put your dreams of becoming the next caped hero on hold. What they can do, however, is improve your sight to the level of a healthy person if your eyesight at night is impaired. They cure night blindness! Vitamin A deficiency is the leading cause of non-accidental blindness worldwide and causes more than 500,000 young children to lose their sight annually. Staggering numbers. So don’t let it happen to you! Make sure you get the right levels of vitamin A (and carrots!) in your diet even if they, dissapointingly, won’t fully let you see in the dark.