Introduction

“Don’t cross your eyes … they’ll get stuck that way!” Did your mother scold you every time you made a crazy face at your brother? In our houses, it was even worse if she caught you sitting too close to the television or she had just caught you reading in the dark. We bet that you still occasionally wonder whether you would need your glasses if you had listened to her.

Your mother had some strong ideas about what would keep you healthy. Use soap! Stay away from that sick person! Don’t shake hands! Don’t touch the toilet! Her rules for taking care of your body went on and on. Without even realizing it, many of us follow all kinds of rules for keeping our bodies healthy. We worry about how public bathrooms and airplanes might make us sick. We try to stay away from eggs and carbonated drinks. We drink warm milk when we cannot sleep. We tell our own children not to sit too close to the television. We even secretly think that handling a toad might give us warts.

Every day, one hears or reads more ideas about how to care for our bodies. We use hydrogen peroxide to clean out our wounds and vitamin E to heal them faster. We eat oysters to get in the mood. We stretch before running to prevent an injury. Have you ever sniffled or coughed in the wrong company? Vitamin C, echinacea, zinc, and neti pots will immediately be foisted upon you as surefire cures for your cold. As we hear more and more information about our bodies, the list of things to be worried about only grows. You better not eat eggs or hot peppers or sugar or chocolate or fish. Caffeine will stunt your growth. Hair dye will hurt your unborn baby. Cell phones and deodorant might give you cancer. Even worse, the list of things you are supposed to avoid seems to change every day.

Sometimes, though, we worry about the wrong things. We worry about wet hair and accidentally touching a toilet when we should be much more worried about smoking or not exercising regularly. But it is easy to worry about the wrong things when we hear them all the time. Your grandmother, your favorite magazine, and even your doctor all may have told you that eggs will give you high cholesterol or that hot peppers will give you an ulcer. If your snot turns green, everyone will want you to run to the doctor for an antibiotic.

We hope this book provides an antidote to many of your worries. Don’t Cross Your Eyes outlines why many of the things you heard from your grandmother or your favorite magazine or even your doctor are actually medical myths.

This book is meant to get you to ask questions. What will really make me sick? How does my body really work? What things actually work to keep my body healthy? We don’t want to get you in trouble with your mother, but we do want to get you thinking about the truth behind all those crazy things you hear about your body and health. We want you to ask “why?”

Many of the things you hear about your body are just not true. They are myths. Some of the ideas are simply unproven, while others have been studied scientifically and proven false. We think that it is silly to waste time, energy, and money worrying about things that will not hurt you. It is just as silly to follow advice that is not going to help you.

As physicians, we want you to be healthy, and we certainly do not want you to get sick. But because we are also researchers, we want you to know the truth about your body. We want our advice to be based on science. If there is good science telling us what will or will not make your body healthy, we think that you should pay attention to it. In our first book, Don’t Swallow Your Gum! Myths, Half-Truths, and Outright Lies About Your Body and Health, we discussed dozens of myths about how your body works. In this book, we are going to examine many more of them. We are not just going to be “experts” telling you what will or will not work to keep you healthy. We are going to explore the science behind various ideas about your health, and we will let the science tell you what you can stop worrying about.

Even though we are doctors (and true geeks) who get excited about research studies and scientific experiments, we know that not everyone feels that way. (Aaron just shed a sad geek tear thinking about people who don’t like science.) Nonetheless, this book—about all the crazy things your mother said about your body—is secretly a science book. We researched each of the ideas in depth, combing the medical and scientific literature for any studies that have been done to tell us the truth about these medical beliefs. Then we try to describe the research in a way that allows you to understand what it says.

Remember, we want you to ask “why?” We don’t want you to believe something is a myth just because we said so. We want you to understand why we said so. That is why we will talk about the research behind each belief and whether good studies give us an answer. Most of the beliefs we examine in this list from A to Z end up being completely false. They are myths or outright lies! Others have some element of the truth. Just a few actually turn out to be true. Whatever the case, we want you to know whether the science comes out in favor or against the belief, and just how convincing the case may be. In the back of the book, you can find a big list of the references for what we say about each myth. We are always scouring the databases for new studies that add more information, and if new studies come out that prove an idea is or is not true, we are happy to change our minds based on that research.

Before you start reading, we offer two words of caution. First of all, some readers of Don’t Swallow Your Gum! told us that the book turned them into the know-it-all at the dinner table or at the party. We love being right, but we also know that people can get annoyed when you are always Ms. or Mr. Smarty-pants. Use discretion. Second, it is always a good idea to show respect for your mother. Even if she is wrong.

Happy myth-busting!