The Myth About Carrots and Vision Started to Foil Nazis

Yesterday, I wrote about how salmon change the form of vitamin A in their eyes to give themselves infrared vision when swimming upstream, improving their ability to see in murky water. In response, a Twitter follower asked:

Sort of. First, vitamin A is an important part of the retina, and carrots are rich in vitamin A, but eating carrots won’t improve your vision. What I didn’t know was that this myth was a deliberate one, manufactured by Allied forces in World War II to foil the Nazis.  Snopes explains:

In World War II, Britain's air ministry spread the word that a diet of these vegetables helped pilots see Nazi bombers attacking at night. That was a lie intended to cover the real matter of what was underpinning the Royal Air Force's successes: Airborne Interception Radar, also known as AI. The secret new system pinpointed some enemy bombers before they reached the English Channel.

British Intelligence didn't want the Germans to find out about the superior new technology helping protect the nation, so they created a rumor to afford a somewhat plausible-sounding explanation for the sudden increase in bombers being shot down. ​

Did it work? The Smithsonian says:

“I have no evidence they fell for it, other than that the use of carrots to help with eye health was well ingrained in the German psyche. It was believed that they had to fall for some of it,” Stolarczyk wrote in an email as he reviewed Ministry files for his upcoming book, tentatively titled How Carrots Helped Win World War II. “There are apocryphal tales that the Germans started feeding their own pilots carrots, as they thought there was some truth in it.”