1 00:00:02,040 --> 00:00:07,120 Speaker 1: Welcome to brain stuff from how stuff works. Hey, brain stuff, 2 00:00:07,160 --> 00:00:10,440 Speaker 1: Lauren vogel Bomb here. Anyone else have the common childhood 3 00:00:10,520 --> 00:00:12,600 Speaker 1: dream to be able to hit clay pigeons with a 4 00:00:12,600 --> 00:00:15,400 Speaker 1: crossbow in the dark at three yards while riding on 5 00:00:15,440 --> 00:00:19,560 Speaker 1: the back of a beautiful pegasus. Just me. Anyway, When 6 00:00:19,600 --> 00:00:22,360 Speaker 1: I told my parents this, they told me, Lauren, if 7 00:00:22,400 --> 00:00:25,120 Speaker 1: you want to have that kind of hyper acute night vision, 8 00:00:25,360 --> 00:00:28,360 Speaker 1: you've got to eat your carrots. It's common wisdom eat 9 00:00:28,360 --> 00:00:29,920 Speaker 1: a lot of carrots if you want eyes like a 10 00:00:30,000 --> 00:00:33,440 Speaker 1: jet pilot. But do carrots really give you better eyesight? 11 00:00:34,320 --> 00:00:36,960 Speaker 1: The short answer is, if you already have enough vitamin 12 00:00:37,000 --> 00:00:39,920 Speaker 1: A in your diet, probably not. But if you don't, 13 00:00:40,080 --> 00:00:42,279 Speaker 1: a big old sack of carrots might be exactly what 14 00:00:42,360 --> 00:00:45,840 Speaker 1: you need. Carrots are packed full of a nutrient called 15 00:00:45,880 --> 00:00:48,519 Speaker 1: beta carotene, which is a kind of natural dye for 16 00:00:48,560 --> 00:00:51,800 Speaker 1: fruits and vegetables. Plans use beta carotene in their bodies, 17 00:00:51,880 --> 00:00:54,480 Speaker 1: is a pigment that gives them a yellow or orange color. 18 00:00:54,920 --> 00:00:57,360 Speaker 1: But when you eat foods containing this natural pigment, like 19 00:00:57,480 --> 00:01:00,160 Speaker 1: sweet potatoes, spinach, or carrots, the beta carrot he can 20 00:01:00,200 --> 00:01:03,400 Speaker 1: gets absorbed by your intestinal wall and converted into vitamin A. 21 00:01:04,480 --> 00:01:07,120 Speaker 1: So here's the true part of the myth. If you 22 00:01:07,160 --> 00:01:09,440 Speaker 1: want to maintain normal eye health, you've got to get 23 00:01:09,560 --> 00:01:12,479 Speaker 1: enough vitamin A, and carrots are a perfectly good source. 24 00:01:13,000 --> 00:01:15,000 Speaker 1: In regions where people don't get much vitamin A and 25 00:01:15,040 --> 00:01:18,600 Speaker 1: their diets, vision problems are rampant. Without vitamin A, the 26 00:01:18,600 --> 00:01:21,520 Speaker 1: photo receptors in your eyes start to deteriorate and your 27 00:01:21,520 --> 00:01:25,600 Speaker 1: corneas can actually vanish. But if you don't have a 28 00:01:25,680 --> 00:01:29,000 Speaker 1: vitamin A deficiency and your vision is already healthy, stuffing 29 00:01:29,000 --> 00:01:30,960 Speaker 1: your face with carrots or any other source of the 30 00:01:31,040 --> 00:01:35,479 Speaker 1: vitamin will not lead to superhuman eyeball powers. So where 31 00:01:35,480 --> 00:01:37,440 Speaker 1: did we get the idea that carrots can do to 32 00:01:37,480 --> 00:01:41,120 Speaker 1: your eyes what spinach does to Popeye's forearms. Believe it 33 00:01:41,200 --> 00:01:43,600 Speaker 1: or not, this myth got a big boost from World 34 00:01:43,600 --> 00:01:47,960 Speaker 1: War two propaganda. During World War Two, the United Kingdom 35 00:01:48,040 --> 00:01:52,120 Speaker 1: underwent air raids conducted by access powers. The German luft 36 00:01:52,120 --> 00:01:54,880 Speaker 1: Buffa would strike at British cities in the night. Over 37 00:01:54,920 --> 00:01:57,680 Speaker 1: the years, the British Royal Air Force had some success 38 00:01:57,680 --> 00:02:01,040 Speaker 1: pushing back the German air attacks. An explanation for their 39 00:02:01,080 --> 00:02:04,680 Speaker 1: success is that from nineteen thirty nine onward. British pilots 40 00:02:04,680 --> 00:02:08,840 Speaker 1: had access to a technology called onboard airborne interception radar 41 00:02:09,080 --> 00:02:11,440 Speaker 1: to help them spot enemy planes for a great distance, 42 00:02:12,040 --> 00:02:15,119 Speaker 1: but the UK Ministry of Food launched a propaganda campaign 43 00:02:15,360 --> 00:02:18,079 Speaker 1: claiming that its fighter pilots could pick out enemy aircraft 44 00:02:18,120 --> 00:02:21,120 Speaker 1: in the dark because they honed their eyes with carrots. 45 00:02:22,040 --> 00:02:24,800 Speaker 1: Some sources have speculated that this story was designed to 46 00:02:24,880 --> 00:02:27,400 Speaker 1: hide the existence of the Royal Air Forces on board 47 00:02:27,480 --> 00:02:31,679 Speaker 1: radar system from the enemy. Another explanation might be simple economics. 48 00:02:32,080 --> 00:02:35,680 Speaker 1: Germans set up blockades to use starvation and discomfort as weapons, 49 00:02:35,840 --> 00:02:38,600 Speaker 1: which meant that many goods like sugar, had to be rationed. 50 00:02:39,040 --> 00:02:42,679 Speaker 1: The UK government encouraged its citizens to turn to sugar substitutes. 51 00:02:43,080 --> 00:02:46,119 Speaker 1: For example, carrots, which were plentiful even during the war, 52 00:02:46,400 --> 00:02:48,799 Speaker 1: could be used as a sweetener in foods like carrot 53 00:02:48,800 --> 00:02:51,880 Speaker 1: pudding and carrot fudge, or as a substitute for meat 54 00:02:51,919 --> 00:02:55,680 Speaker 1: in the infamous Wolton pie. Carrots were so plentiful because 55 00:02:55,680 --> 00:02:57,919 Speaker 1: they could be grown by citizens at home and around 56 00:02:57,960 --> 00:03:01,880 Speaker 1: their communities in so called victory gardens. Food supplies were 57 00:03:01,880 --> 00:03:04,720 Speaker 1: low due to those blockades, and canned fruits and vegetables 58 00:03:04,800 --> 00:03:08,000 Speaker 1: largely went to feed the military. Citizens were encouraged to 59 00:03:08,080 --> 00:03:10,560 Speaker 1: make up the difference. The slogan of the campaign was 60 00:03:10,680 --> 00:03:14,680 Speaker 1: dig for Victory. Two million private gardens were constructed and 61 00:03:14,760 --> 00:03:17,360 Speaker 1: some public ones as well. The dry moat surrounding the 62 00:03:17,400 --> 00:03:25,760 Speaker 1: Tower of London was filled in with growing vegetables. Today's 63 00:03:25,760 --> 00:03:28,560 Speaker 1: episode was written by Joe McCormick and produced by Tyler Clang. 64 00:03:28,880 --> 00:03:30,880 Speaker 1: For more on this and lots of other sharp topics, 65 00:03:30,960 --> 00:03:44,480 Speaker 1: visit our home planet, how Stuff Works dot com.