“Eat your carrots, it will improve your eyesight”. This is a phrase frequently repeated by parents to coax their children into eating carrots. The problem is it’s a complete lie, adding more evidence that everything I learned as a child was a lie.
Origins of a Lie
Uncovering where this lie came from requires a journey through history involving war, radar technology, counter-intelligence, John “Cat-Eyes” Cunningham, and Nazis.
During WWII, the British Royal Air Force developed an experimental airborne radar to help combat the Luftwaffe which frequently carried out attacks under the cover of darkness. It was a huge success with John “Cat-Eyes” Cunningham among the first to shoot down German planes using the airborne radars.1 He went on to destroy at least 20 enemy aircraft. The Ministry of Information began to attribute the Royal Air Force’s newfound success to feeding their pilots (like Cunningham) a carrot rich diet. This was part of an effort to prevent the Germans from suspecting they had radar equipped planes.2 While there is no concrete proof to confirm the German military was fooled, we do know that it led to a flood of reports and posters encouraging citizens to increase consumption of carrots. Thus, a lie was born. Sadly it was not relegated to wartime propaganda and the perception continues to this day.
The best place to start in fact-checking this myth is a quick examination of why most people have poor eyesight. Then a simple cross reference of available information can show whether or not carrots help with any of those issues.
The World Health Organization’s fact sheet shows the biggest problems with eyesight are cataracts (33%) and 3 basic refractive problems (combined 43%); nearsightedness (myopia) farsightedness (hyperopia), and astigmatism.3
Cataracts is caused by clumps of protein clouding the lens in the eye, usually getting progressively worse.
The major causes of myopia are all related to the physical deformation of the eye. Usually the eyeball is too long from front to back, other times the is cornea overly curved relative to the length of the eyeball or the lens is too thick. This causes light rays to focus at a point in front of the retina, rather than on its surface which blurs objects at a distance.
Inversely, hyperopia occurs when the eyeball is too short or has abnormal shapes of the cornea or lens. The physical deformations focus images behind the retina instead of on the retina blurring images when they are up close.
Astigmatisms occur when the cornea’s shape is more asymmetrical (resembling a football). This prevents the eye from focusing light on a single point and causes vision to be blurred at any distance.
Studies have shown prevalences in the U.S. of hyperopia, myopia, and astigmatism were 3.6% , 33.1% , and 36.2%, respectively with a 95% confidence interval.4
Carrots are rich in Beta-Carotene which is converted by the small intestine into Vitamin A.5 However, eating carrots won’t change eye shape and won’t help heal refractive problems of the eye,6 which is why treatments include glasses, contact lenses, and eye surgery. Not carrot consumption.
This study published by Karger showed “no positive or negative effect” of Beta Carotene on cataracts going on to conclude any improvements noted were “of no clinical or public health significance”.7 A meta-analysis of published relevant studies confirms that Beta Carotene “had no significant association with risk of cataract”.8
So, can any connection be made with carrots and eye health? Interestingly, yes. A lack of Vitamin A can lead to deterioration of eyesight. However Vitamin A does not improve vision unless the individual has extreme deficiencies that are being brought back to normal levels (very rare for this to happen in developed countries). Furthermore, the conversion of Beta Carotene into Vitamin A is not very efficient, most individuals would be better served with a direct Vitamin A supplement. Fortified rice, retinyl palmitate, and liver have proven just as effective.9
In conclusion, everything I learned as a child was a lie, carrot consumption does not improve eyesight, and everyone should take carrots out of their cakes, off of their plate, and put them exactly where they belong: in the trash!!!
- Group Capt John ‘Cat’s Eyes’ Cunningham The Telegraph – Obituaries 23 Jul 2002 [↩]
- A WWII Propaganda Campaign Popularized the Myth That Carrots Help You See in the Dark by K. Annabelle Smith [↩]
- World Health Organization Vision impairment and blindness Fact Sheet Updated October 2017 [↩]
- Prevalence of refractive error in the United States, 1999-2004. Vitale S, Ellwein L, Cotch MF, Ferris FL 3rd, Sperduto R. [↩]
- Mammalian Metabolism of β-Carotene: Gaps in Knowledge Varsha Shete and Loredana Quadro [↩]
- The role of topical vitamin A in promoting healing in surface refractive procedures: a prospective randomized controlled study by Elias Chelala, Ali Dirani, Ali Fadlallah, and Sharbel Fahd [↩]
- Nutritional Supplementation to Prevent Cataract Formation by Meyer C.H. · Sekundo W. [↩]
- Association of blood antioxidants and vitamins with risk of age-related cataract: a meta-analysis of observational studies. Cui YH, Jing CX, Pan HW. [↩]
- Recovery from impaired dark adaptation in nightblind pregnant Nepali women who receive small daily doses of vitamin A as amaranth leaves, carrots, goat liver, vitamin A-fortified rice, or retinyl palmitate. Haskell MJ, Pandey P, Graham JM, Peerson JM, Shrestha RK, Brown KH. [↩]
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