This fortnight, Alison Lee discusses carrots and their supposed ability to enhance your vision
I’m sure once upon a time you were urged by your granny to “eat up your carrots, they make you see in the dark”. Maybe you have traumatic memories of wolfing down carrots and waiting impatiently for superpowers worthy of the average X-Man to be conferred upon you. Then you ended up feeling betrayed when you developed short-sightedness and became the kid with the thick glasses.
But no, your granny wasn’t playing a malicious trick on you. The carrot, that humble, phallic, orange vegetable, is packed full of beta-carotene. This is converted to retinol (the storage form of vitamin A) and stored in the liver, from where it can be mobilised whenever the body needs it.
Why does the body need vitamin A? This chemical is essential for proper formation of rod cells in the eye. These cells contain photopigments made of retinal (a slightly modified version of retinol) and proteins called opsins. Together, they form a complex called rhodopsin and are sensitive to light. The rod cells are adapted for night vision – they’re highly sensitive to light of all wavelengths, though they’re not so good at picking up the direction from which the light comes.
In contrast, the cone cells of the eye, which are adapted for colour vision, are less light sensitive but they’re better at sensing the directionality of light. So yes, if you eat your carrots, you’ll have more retinal in your body, and therefore you’ll have more sensitive night vision.
Bizarrely, this myth originates from the First World War. The British Royal Air Force, wanting to conceal the fact that they had developed airborne interception radar (AI), circulated the rumour that their pilots were fed carrots to improve night vision. This hit the papers at the time and helped propagate the myth. The fact is they didn’t want the Germans to know how they were intercepting their bombers even in the depths of night.
Myth aside, you can get beta-carotene from plenty of other foods. Orange fruits and vegetables like sweet potatoes or apricots are rich in beta-carotene and if vegetables aren’t your thing, then pig out on fish, liver and eggs.
Night-vision isn’t all carrots have to offer. They could also provide a healthy and less streaky alternative to fake tan. That’s because if you overdo the carrot eating, the beta-carotene pigment builds up in your skin and turns you orange. It’s the San Tropez of the recession!
But beware of eating pure vitamin A – beta-carotene, the vitamin A precursor, is non-toxic. But large quantities of preformed vitamin A, found for example in liver, can cause vitamin A toxicity. This involves a whole range of nasty symptoms like hair loss, headaches, nausea, anaemia, and diarrhoea. Bad news for all the foie gras fans out there but congratulations to all the carrot lovers.