If your parents ever told you that eating carrots would improve your eyesight, you can consider yourself a victim of World War II propaganda. The myth dates back to the early 1940s and a famous misinformation campaign by the British government. At the time, the Royal Air Force was utilizing a new onboard radar system called Airborne Interception Radar, which allowed their pilots to more effectively target German bombers during nighttime missions. To keep the true source of their higher kill counts under wraps, the RAF spread a rumor that its fighter aces’ cat-like night vision was the result of a steady diet of vitamin-rich carrots.

Strange though it may seem, the claim wasn’t entirely bogus. Carrots are a good source of beta-carotene, which the body converts to vitamin A—a crucial component of overall eye health. But while carrots might help the vision of a person with severe malnutrition, gobbling down excess amounts of them won’t allow you to suddenly ditch your glasses or see better in the dark. In fact, too much vitamin A can be toxic.

There’s no evidence that Britain’s carrot propaganda actually fooled the Nazis, but it did stick in the public consciousness. Spurred on by posters and news reports claiming carrots would help with their “night sight” during wartime blackouts, many British citizens began serving up heaping portions on their dinner tables and growing them in their “victory gardens” at home. The Ministry of Food even introduced a cartoon character named “Dr. Carrot” to make them more palatable to children. By the time the war ended, Britain had produced a surplus of carrots, and the vegetable’s reputation as an eye-fortifying superfood had cemented itself in popular lore.