Check, please!

Biologists debunk an 80-year-old myth about carrots

Can carrots give you super-eyesight? Maybe not.

As children, we often first learn about the benefits of food through the white lies and myths our parents pass down. Those carrots you’re pushing around your plate, for example, could give you superhero-like eyesight — if only you’d finish your serving.

This foodie myth may be an effective way to convince children to try these bright orange vegetables, but just how much weight should we put behind it as adults?

With a past rooted in World War II propaganda and a future of potential cataract protection, development and molecular biologists help Inverse get to the root of carrots.

The history of WWII carrot propaganda

Carrots have been cultivated from their more bitter, wild form for over 2,000 years, but John Stolarczyk and Jules Janick, founder and curator of the digital World Carrot Museum and professor of horticulture respectively, write in a 2011 historical review that World War II can be credited with the popularity carrots see today.

“World War II revived the popularity of the carrot, elevating it from a mere animal feed to a major food source,” Stolarczyk and Janick write. “The character Doctor Carrot was devised in 1941 by the UK Ministry of Food to promote carrots as a substitute for other more scarce vegetables in the campaign called Dig for Victory.”

During WWII, carrots weren’t only an easy vegetable to grow in victory gardens but potentially a key weapon against opposing forces too.Image courtesy of Flickr user US National Archives Bot

Carrots were an easy and relatively hearty vegetable that Brits could grow in their victory gardens to alleviate food shortages during the war and could even be used to replace sugar (a sparse pantry staple at the time) in recipes, such as carrot marmalade.

“Eating carrots does not improve your vision, but the lack of vitamin A can cause night blindness, and carrots are high in vitamin A.”

The pair writes that the idea of carrots improving night blindness — or even, boosting night vision — stems from a connection between war-time diets, the London Blitz, and misdirection to the opposing German forces.

“The British government... put out a story that the consumption of special high carotene carrots was the reason for the success of the Royal Air Force gunners during the blitz, as a ruse to obscure the launch of the new airborne radar system as well as the use of red light (which helps preserve night vision) in aircraft instruments,” Stolarczyk and Janick write.

“Eating carrots does not improve your vision, but the lack of vitamin A can cause night blindness, and carrots are high in vitamin A.”

How do carrots affect eyesight?

Carrots are full of an eyesight influencing class of carotenoids (a plant-produced orange pigment) called beta carotene, which the body can convert into vitamin A, as well as lutein, which impacts retina health.

A 1942 ad for “Doctor Carrot.” Imperial War Museums via Getty Images

“Beta carotene itself is not directly related to vision but vitamin A is,” Hasan Mahmud Reza, a professor of pharmaceutical science at North South University in Bangladesh who contributed to a study of these vitamins, tells Inverse.

“Lutein protects the photoreceptors and the chromophores of the retina from oxidative stress in the presence of oxygen, light, and heat,” Reza says.

In addition to promoting eye health, maintaining your body’s vitamin A levels (which Mayo Clinic recommends as between 700 to 900 micrograms per day) can also positively influence your body’s immune and reproductory systems.

Does this mean that carrots should be your one-stop shop for eye care? Not necessarily, T. Michael Redmond, a senior investigator at the National Eye Institute, tells Inverse.

When it comes to eye health, vitamin A helps proteins in the eye form both cone cells and rod cells which work in concert to parse the light intensity and color from an onslaught of otherwise unintelligible lightwaves.

But just because carrots contain beta carotene, as well as lutein which impacts retina health, doesn’t mean they should necessarily be your primary source of beta carotene let alone vitamin A.

Can eating carrots reverse or improve bad eyesight?

One way that beta carotene-derived vitamin A can help improve diminished eye health, explains Redmond, is in the instance of a vitamin A deficiency.

Such a deficiency can lead to night blindness Redmond says, where one’s ability to see in low-light (such as in a dim restaurant or driving at night) becomes impaired.

“The slower way would be eating a lot of carrots.”

Not all night blindness stems from vitamin A deficiency, but when it does, studies have shown that vitamin A can be used as a way to reverse it, Redmon says.

That said, Redmond doesn’t necessarily recommend eating a pile of carrots to feel this effect.

Instead, consuming a supplement like cod oil to restore vitamin A levels will “will quickly replenish the eye and will reverse night blindness,” says Redmond. “That's the quickest way to do this. The slower way would be eating a lot of carrots.”

But if you’re hell-bent on receiving your vitamin A through vegetables, Redmond suggests mixing your carrots with leafy greens or beta carotene sources like sweet potato or pumpkin, as well as a full-fat dressing to improve the absorption of the carotenoids. This is especially important because the conversion process itself between plant-based beta carotene and vitamin A can be incredibly inefficient, Redmond explains, with 12 molecules of beta carotene transforming into only a single vitamin A molecule.

Cheese puffs aren’t the only food that will turn your skin orange.

Can you eat too many carrots?

Not only would eating piles of carrots inevitably become unpleasant, but Redmond says that studies on the impact of beta carotene and cataracts have found that consuming too much beta carotene can actually have a negative impact on the body, including the development of lung cancer in smokers.

Consuming too many carrots can also turn your skin orange says Redmond — yes, just like in The Magic School Bus.

Overall, Redmond says that carrots can be a good addition to one’s diet, as long as they’re consumed — like all foods — in moderation.

“The absolute main point is a balanced diet,” says Redmond.

CHECK, PLEASE is an Inverse series that uses biology, chemistry, and physics to debunk the biggest food myths and assumptions.

Now read this: Food scientists debunk a dangerous myth about moldy food

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