Does Eating Carrots Really Help You See Better?
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Lately, I have been drawing inspiration from some of the question that kids ask a lot. I recently wrote about what causes stuff to taste weird after we brush our teeth, and now I am going to tackle another frequently asked question: ”Does eating carrots really help your eyesight?” It turns out, this is a very loaded question with lots of interesting historical significance and a tiny hint of government conspiracy sprinkled in.
As a kid, I use to eat a lot of carrots. Not only did I like the taste, but I was also a big fan of Looney Tunes. I would chomp up a bite of carrot, walk up to my sister, and say, “Ehhhhh, what’s up, doc?” Of course, I was always sure to spew carrot chunks all over the place in the process. I also had pretty good eyesight. Any time someone would ask me, “How did you see that from so far away?”, I would answer it was because I ate a lot of carrots. I don’t even remember where I first learned that little knowledge-nugget, but I wholeheartedly believed it. However, sometime between then and now, doubt has crept in. Again, I don’t remember what I read or heard that caused me to change my mind; but the last time anyone asked me this question, my initial response was that I didn’t know, but I figured it was just some type of urban legend. I don’t like to give people false information, so I figured I would do a little research and find out the truth.
The Claim
But First, A Little Bit Of History
The WWII Connection
I found out that there is actually a very interesting connection between our carrot claim and World War II. I don’t think it is where the idea originated, but it definitely had a lot to do with popularizing it.
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In 1940, the Luftwaffe, or German Air Force shifted its Blitzkrieg tactics toward Britain. Nazi generals expected another quick victory in their lightning war, but they greatly underestimated the British military might and strategy. The Germans had a tendency to make their bombing runs under the cover of night, so the British government began enforcing mandatory blackouts hoping that German pilots would have a difficult time finding their targets. These were serious blackouts with reports of people being arrested just for striking a match outdoors! But, the tactic worked. Furthermore, British forces were somehow able to see the German planes even in the pitch black of night. John “Cat Eyes” Cunningham, is said to have been the first RAF pilot to have shot down a German plane at night. He would go on to take down a total of 20 enemy fighters, with 19 of those coming during blackout hours. The British government attributed his keen night vision to all of the carrots that he ate. They went on to launch a public campaign espousing the advantages of eating lots of carrots and leafy greens. While some believe this official statement was a ploy to keep their new on-board radar technology a secret from Nazi intelligence, the Germans were probably well aware of RAF capabilities. Instead, it was likely a case of subterfuge aimed at its own people. At the time, imported foods were difficult to come by. Vegetables like carrots and greens could easily be grown domestically. People could even grow them in their own yard! By convincing the general public that a diet full of tasty homegrown vegetables would help them see better during the blackouts, they were taking some of the load off of their rationed food portions.
Now, Some Science
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Parts Of The Eye
Before we dig in to find out whether carrots are good for our vision, we probably need a quick primer on how the eye works. The major parts that we will be concerned with are the sclera, cornea, iris, pupil, lens, retina, and optic nerve.The sclera is the white part of the eyeball. When I was little, I always imagined that an eyeball would be squishy and gelatinous; kind of like a peeled grape. I didn’t find out that I was wrong until I started teaching science and dissected my first cow eyeball with my students. The sclera is made up of tough interlacing collagen fibers that make it very tough. It actually feels kind of leathery, which is good since its primary functions are to protect the eye from external damage and maintain proper internal pressure.
The cornea is the clear protective layer that covers the iris and pupil. The sclera overlaps the cornea on the top and the bottom, forming a seamless transition. In addition to its protective function, it also provides up to 75% of the eye’s focusing power.
The iris is the colored part of the eyeball. The iris is an example of a circular muscle called a sphincter muscle. There are more than 50 sphincter muscles in the body. Most of them are located in the digestive system, and they are used to control the flow of material from one place to another. This sphincter in your eye dilates and contracts to control the amount of light that gets into the eye. The color comes from the melanin that is contained in the iris. The more melanin, the darker the eye color. While eye color doesn’t really affect visual acuity, it may make a difference in how you handle bright lights. In individuals with darker colored eyes, the iris absorbs more light, keeping it from entering the pupil. These people generally experience less discomfort under bright lights.
The pupil is the round opening in the center of the iris. To me, it is one of the coolest parts of the eye. First of all, it is literally just a hole in your eye. If it wasn’t for the cornea, you could poke your pinky straight into your eyeball and touch the lens! I also think it’s cool that the pupil is black. Black is the absence of color. If an object appears black, then it is absorbing all of the light that is striking it. No light is bouncing back into your eye, and your brain interprets this as black. When light enters the pupil, it gets focused by the lens onto the back of the eye. No light is coming back out, so everyone else sees it as a black hole.
The lens is a crystal clear, biconvex object that lies just behind the pupil. As light enters the eye, the lens focuses all of it toward the retina. Muscles around the lens can move, bend, or flex it to fine focus on the tiniest of details. Compare this to even the best of cameras, which require a series of lenses and mirrors to accomplish the same task!
The retina is the a thin layer of tissue that covers the back, inside portion of the eyeball, where it plugs in and becomes the optic nerve. The retina has a texture that I would compare to a wet Kleenex. It is the part of the eyeball that turns light into a nerve impulse using specialized receptor cells called rods and cones. The rod cells simply detect the presence of light, so they provide us with black-and-white vision. Cone cells are further specialized to detect only light of specific wavelengths, so they give us our color vision. This is the part of the eye that we will focus on for the remainder of this article.
The Carrot Claim
It appears as if our carrot claims are at least rooted in fact. Carrots contain a pro vitamin called beta carotene, which is converted to vitamin A in the body, and vitamin A is very important for proper eye function. Specifically, it can be turned into rhodopsin, which is the pigment responsible for light detection in rod cells. Since rod cells detect the presence of any light in the visible spectrum, they are the ones that give us our night time vision.On an interesting side note
Try this: go outside on a star-lit night and look up. Find a dim star in your peripheral vision, and then look straight at it. Did it disappear? Now, put it back in your periphery. Did it reappear? This use to drive me crazy until I learned about where our rod and cone cells are concentrated. We have the highest concentration of rod cells on the outer parts of the retina, so we can actually detect light better with our peripheral vision, while our color-detecting cone cells are concentrated in the center of the retina.Furthermore, fruits, vegetables, and leafy greens are also high in vitamins C, E, and lutein, which act as antioxidants in the body. When rod and cone cells in the retina work, they give off free radical oxygen atoms as a byproduct. Free radicals volatile are atoms that have unpaired electrons. They roam around the body looking for a way to get more electrons, often times destroying important compounds in the process. Antioxidants give free radicals the electrons that they are seeking before they have a chance to cause damage to the body. So in theory, a diet high in antioxidant-containing veggies should slow down the development of things like cataracts and age-related macular degeneration, though some studies have shown mixed results.
In Conclusion
It does appear that eating carrots might help to improve a person’s night vision, but only if that person suffered night blindness due to a prior vitamin A deficiency. This seems to be the only way our diet might improve our vision; however, we may be able to stave off the deterioration of our eyesight by eating a diet rich in vitamins A (or beta carotene), C, E, and lutein.I’ll be honest, I went into this article expecting to completely debunk the ”myth” that carrots were good for your eyesight; and, while I did find that claims of improved night vision have been blown out of proportion, I was surprised to find that they are built on a solid base. I would imagine that the link between carrot eaters and night vision probably began long ago before our modern diets ensured that we a surplus of nutrients to nourish our eyes. Back then, it would make sense that those who avoided carrots and other veggies would be lacking in vitamin A and would therefore have noticeably poorer night vision. The idea may have remained nothing more than an obscure legend had it not been ingrained into our psyche by Brittain’s “eat more veggies” campaign during WWII. Either way, whether you get them in your diet or by taking supplements, evidence shows that vitamins A, C, E, and a handful of others are important for maintaining eye health. So, EAT YOUR VEGETABLES!
