字幕表 動画を再生する 英語字幕をプリント “Sugar makes children hyper”. We’ve all heard this before and maybe you’ve even observed it in kids. But actually it's a misconception. There are lots of widely believed misconceptions about science that are just plain wrong – like “You only use ten percent of your brain”. You really use one hundred percent of your brain. I hope that doesn’t surprise you. These are few misconceptions about sugar that I’ve noticed in the past few months. Sugar Makes Children Hyperactive At least a dozen studies have looked at how children behave on diets containing different levels of sugar – both natural sugars you find in fruit and added sugars you find in chocolate or candy and lollies. None of these studies found significant differences in behaviour between kids who had sugar and kids that didn’t. And in another study, parents who thought their kids had just consumed a sugary drink, rated their kids’ behaviour as more hyperactive. Even though that drink was really sugar free. Often it’s kids surroundings that influence them to be hyper – they’re excited, with friends or at a birthday party. And parents often attribute this behaviour to sugar. Sugar rots your teeth It is correct to say that sugar can cause tooth decay, but technically it doesn’t directly rot your teeth. In your mouth you have 500 to 1000 different types of bacteria, kind of gross. And a few species of these are thought to cause cavities. The main culprit is Streptococcus mutans. S. mutans loves to feed on the carbohydrates left on your teeth as residue, from sugars or from starch in bread or potatoes. From this S. mutans produces high levels of lactic acid, which diffuses into the tooth and your enamel begins to dissolve. Of course, the more sugar you eat, the more residue you have left on your teeth. Certain areas on your tongue sense different tastes You may have seen this well-structured Tongue Map before, but there’s no one area for different taste receptors on your tongue. This myth is thought to originate from one study in 1901, but it wasn’t debunked until 1974. Really, your taste buds are all over your tongue. They live in your papillae, the tiny bumps that give your tongue its rough texture. In your taste buds there’s different cells so they respond to sweet, sour, salty, bitter or umami tastes – umami being the taste of glutamate that gives meat and delicacies like Vegemite their savory flavour. Your taste cells have 50 to 150 receptors for each taste, when they’re stimulated they send messages to the brain, where those specific tastes are perceived. Now, the reason I noticed these misconceptions is because I actually believed a couple of them myself. You may have seen the episodes I did last month on sugar – I did quite a lot of research for them and even had someone fact check my scripts. But, I'd still included a couple of things that weren’t entirely correct. DeluxeFlame and some others pointed out “When you talked about sweetness receptors on the tongue, you showed an image that highlighted the tip of the tongue. Correct me if I’m wrong but isn’t that a myth proven busted? The whole tongue senses all tastes.” And you’re totally right, it does. rdizzy pointed out, “Studies have shown recently that it’s not sugar at all that causes tooth decay, it’s lactic acid produced from bacterium eating sugar that stays on the teeth for too long.” Yes and yes! But keep in mind that sugar is pretty central to that loop. What I find most concerning is that the tongue map myth was busted in 1974. When I was in high school, which wasn’t all that long ago, the tongue map was in our textbooks, and, after that, when I was teaching, the tongue map was in our teaching materials. I never questioned it and I still believed it years later. As Richard Feynman said, "The first principle is that you must not fool yourself and you are the easiest person to fool." So I just wanted to say a big thank you for all of your comments, I definitely appreciate them, I read all of them and this show wouldn’t be what it is without you guys and what you have to say. See you next week.