Know Your Food
Know Your Food
Know YOur Food
Fats and Cholesterol Fiber Flavorings, Colorings, and Preservatives Food Safety Genetically Modif ied Foods Gluten Organic Foods Protein Salt Starch and Other Carbohydrates
Sugar and Sweeteners Vitamins and Minerals Water
Know Your Food
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© 2018 by Mason Crest, an imprint of National Highlights, Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, taping, or any information storage and retrieval system, without permission from the publisher. MTM Publishing, Inc. 435 West 23rd Street, #8C New York, NY 10011
www.mtmpublishing.com President: Valerie Tomaselli Vice President, Book Development: Hilary Poole Designer: Annemarie Redmond Copyeditor: Peter Jaskowiak
Editorial Assistant: Leigh Eron Series ISBN: 978-1-4222-3733-5
Hardback ISBN: 978-1-4222-3742-7 E-Book ISBN: 978-1-4222-8049-2 Library of Congress Cataloging-in-Publication Data Names: Centore, Michael, 1980- author. Title: Salt / by Michael Centore. Description: Broomall, PA: Mason Crest,  | Series: Know your food | Audience: Ages 12+. | Audience: Grades 7 to 8. | Includes index. Identifiers: LCCN 2016053137 (print) | LCCN 2016054927 (ebook) | ISBN 9781422237427 (hardback : alk. paper) | ISBN 9781422280492 (ebook) Subjects: LCSH: Salt—Juvenile literature. | Food—Sodium content—Juvenile literature. | Sodium—Physiological effect—Juvenile literature. | Nutrition—Juvenile literature. Classification: LCC TN900 .C46 2018 (print) | LCC TN900 (ebook) | DDC 613.2/8522—dc23
LC record available at https://lccn.loc.gov/2016053137 Printed and bound in the United States of America. First printing 9 8 7 6 5 4 3 2 1 QR CODES AND LINKSTOTHIRD PARTY CONTENT
Table of Contents
Series Introduction . . . . . . . . . . . . . . . . . . . . . . 6 Chapter One: The Many Uses of Salt . . . . . . . . . . . . . . . 9 Chapter Two: Salt in History . . . . . . . . . . . . . . . . . . 21 Chapter Three: Salt and the Human Body . . . . . . . . . . . . . 33 Chapter Four: Salt in Food . . . . . . . . . . . . . . . . . . . 45 Further Reading . . . . . . . . . . . . . . . . . . . . . . . 55 Series Glossary . . . . . . . . . . . . . . . . . . . . . . . 57 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 About the Author . . . . . . . . . . . . . . . . . . . . . . 64 Photo Credits . . . . . . . . . . . . . . . . . . . . . . . . 64 Words to Understand: These words with their easy-to-understand definitions will increase the reader’s understanding of the text, while building vocabulary skills. Sidebars: This boxed material within the main text allows readers to build knowledge, gain insights, explore possibilities, and broaden their perspectives by weaving together additional information to provide realistic and holistic perspectives. Educational Videos: Readers can view videos by scanning our QR codes, which will provide them with additional educational content to supplement the text. Examples include news coverage, moments in history, speeches, iconic sports moments, and much more. Text-Dependent Questions: These questions send the reader back to the text for more careful attention to the evidence presented there. Research Projects: Readers are pointed toward areas of further inquiry connected to each chapter. Suggestions are provided for projects that encourage deeper research and analysis. Series Glossary of Key Terms: This back-of-the-book glossary contains terminology used throughout the series. Words found here increase the reader’s ability to read and comprehend higher-level books and articles in this field.
Key Icons to Look for:
SERIES Introduction I n the early 19th century, a book was published in France called Physiologie du goût ( The Physiology of Taste ), and since that time, it has never gone out of print. Its author was Jean Anthelme Brillat-Savarin. Brillat-Savarin is still considered to be one of the great food writers, and he was, to use our current lingo, arguably the first “foodie.” Among other pearls, Physiologie du goût gave us one of the quintessential aphorisms about dining: “Tell me what you eat, and I will tell you what you are.” This concept was introduced to Americans in the 20th century by a nutritionist named Victor Lindlahr, who wrote simply, “You are what you eat.” Lindlahr interpreted the saying literally: if you eat healthy food, he argued, you will become a healthy person. But Brillat-Savarin likely had something a bit more metaphorical in mind. His work suggested that the dishes we create and consume have not only nutritional implications, but ethical, philosophical, and even political implications, too. To be clear, Brillat-Savarin had a great deal to say on the importance of nutrition. In his writings he advised people to limit their intake of “floury and starchy substances,” and for that reason he is sometimes considered to be the inventor of the low-carb diet. But Brillat-Savarin also took the idea of dining extremely seriously. He was devoted to the notion of pleasure in eating and was a fierce advocate of the importance of being a good host. In fact, he went so far as to say that anyone who doesn’t make an effort to feed his guests “does not deserve to have friends.” Brillat-Savarin also understood that food was at once deeply personal and extremely social. “Cooking is one of the oldest arts,” he wrote, “and one that has rendered us the most important service in civic life.” Modern diners and cooks still grapple with the many implications of Brillat- Savarin’s most famous statement. Certainly on a nutritional level, we understand that a diet that’s low in fat and high in whole grains is a key to healthy living. This is no minor issue. Unless our current course is reversed, today’s “obesity epidemic” is poised to significantly reduce the life spans of future generations. Meanwhile, we are becoming increasingly aware of how the decisions we make at supermarkets can ripple outward, impacting our neighborhoods, nations, and the earth as
a whole. Increasing numbers of us are demanding organically produced foods and ethically sourced ingredients. Some shoppers reject products that contain artificial ingredients like trans fats or high-fructose corn syrup. Some adopt gluten-free or vegan diets, while others “go Paleo” in the hopes of returning to a more “natural” way of eating. A simple trip to the supermarket can begin to feel like a personality test—the implicit question is not only “what does a healthy person eat?,” but also “what does a good person eat?” The Know Your Food series introduces students to these complex issues by looking at the various components that make up our meals: carbohydrates, fats, proteins, vitamins, and so on. Each volume focuses on one component and explains its function in our bodies, how it gets into food, how it changes when cooked, and what happens when we consume too much or too little. The volumes also look at food production—for example, how did the food dye called Red No. 2 end up in our food, and why was it taken out? What are genetically modified organisms, and are they safe or not? Along the way, the volumes also explore different diets, such as low-carb, low-fat, vegetarian, and gluten-free, going beyond the hype to examine their potential benefits and possible downsides. Each chapter features definitions of key terms for that specific section, while a Series Glossary at the back provides an overview of words that are most important to the set overall. Chapters have Text-Dependent Questions at the end, to help students assess their comprehension of the most important material, as well as suggested Research Projects that will help them continue their exploration. Last but not least, QR codes accompany each chapter; students with cell phones or tablets can scan these codes for videos that will help bring the topics to life. (Those without devices can access the videos via an Internet browser; the addresses are included at the end of the Further Reading list.) In the spirit of Brillat-Savarin, the volumes in this set look beyond nutrition to also consider various historical, political, and ethical aspects of food. Whether it’s the key role that sugar played in the slave trade, the implications of industrial meat production in the fight against climate change, or the short-sighted political decisions that resulted in the water catastrophe in Flint, Michigan, the Know Your Food series introduces students to the ways in which a meal can be, in a real sense, much more than just a meal.
SERIES Introduction T K TK
Chapter 1 The Many Uses of Salt
W ords to U nderstand brine: water containing a high amount of salt. compound: a substance formed when two or more chemical elements join together. crystalline: having the form of a crystal, with particles that are arranged in regular, repeated structures. evaporite: a salt or mineral deposit left behind as a body of water evaporates over time. freezing-point depression: when the freezing point of a liquid is lowered by adding another substance to it. ionic bond: a bond formed between two electrically charged atoms called ions. lattice: a regular arrangement of chemical particles. processed food: food that has been refined before resale, often with additional fats, sugars, sodium, and other additives. savory: a spicy or salty quality in food. Y ou’ve sprinkled it on your french fries, tasted its coarse grains on pretzels at the ballpark, and noticed it on every restaurant table right next to the pepper. Maybe you’ve seen trucks scatter it over icy roads in wintertime,
or gotten a mouthful of it during your last swim in the ocean. It’s one of the five main taste qualities your tongue can perceive, along with sweet, sour, bitter, and umami, and it has been claimed to have some 14,000 uses. We’re talking, of course, about salt. This humble white substance seems to be everywhere (and, with all the processed foods in our modern diets, it actually kind of is), so we often consume it without giving it much thought. We forget that for thousands of years, it was a highly prized source of income and trade, as well as the many ways it is essential to our health. No matter how we encounter it, salt is a building block of life that goes well beyond just enhancing our taste buds. T he B asic C hemistry of S alt In chemistry, a salt is a special kind of compound formed by the reaction between an acid and a base. The negative charge in the acid and the positive charge in the base come together to form an ionic bond that creates the salt. Salts can be many colors,
Potassium dichromate is a salt that’s used in cement as well as in photography and screen printing.
The Many Uses of Salt
The Salar de Uyuni
The largest salt flat in the world is the Salar de Uyuni in Bolivia, covering 4,086 square miles. This flat is located in the Altiplano (high plain) region, an elevated plateau that formed with the rise of the Andes Mountains. Around 30,000 to 40,000 years ago, much of this area was covered by the prehistoric Lake Minchin. Throughout the centuries, this lake began to evaporate, breaking up into smaller lakes and dry areas. Eventually, only the modern Poopó and Uru Uru lakes and the Salar de Uyuni and Salar de Coipasa salt flats were left. In 2016, scientists confirmed that Poopó, the country’s second-largest lake, had dried up due to climate change, the effects of the weather system El Niño, and poor management of water resources. Sadly, the drying of the lake has displaced people who lived nearby and depended on it for their livelihoods. Climate change scientists say that the same thing can happen to other lakes and reservoirs around the world as temperatures rise and more water evaporates than can be replaced.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ Salar de Uyuni, in Bolivia.
and they can have different tastes. For example, a type of toxic salt used to make bleach is called potassium dichromate, which is orange in color. Potassium bitartrate, a salt that forms in wine casks and is also known as cream of tartar, doesn’t taste “salty” at all—it has a sour flavor. Some salts even have particular odors, depending on their chemical makeup. All these salts have their uses, but by far the most common is sodium chloride, or table salt, the stuff we use to season and preserve our food. Sodium chloride is a compound formed by a reaction between hydrochloric acid (an acid) and sodium hydroxide (a base). In the reaction, sodium and chlorine atoms create strong ionic bonds. The bonds make a three-dimensional lattice , which gives salt its characteristic crystalline structure. The reaction also produces water. You may sometimes see sodium chloride written as NaCl; that’s its chemical formula. The “Na” is the chemical abbreviation for the element sodium, and the “Cl” stands for chlorine. Chloride is the name for chlorine that has an electric charge. A mind-bending fact is that, separately, both sodium (a metal) and chlorine (a gas) are toxic to humans, yet when they bond, they create something we ingest every day! S alt in N ature Sodium chloride is found in nature in many forms. One is its mineral form, called halite or rock salt. Large deposits of halite exist underground on every continent on earth. It is also found as an evaporite around salt lakes. These are lakes formed when mineral- and salt-rich water f lows into a lake that is “closed,” which means it has no way of draining. When this water evaporates in the sun, salts and minerals are left behind. In some arid desert climates, ancient lakes have evaporated completely over thousands of years. All that remains are vast stretches of salts and minerals called salt flats or salt pans. One of the most famous salt flats in the world is the Bonneville Salt Flats in Utah, which was created by the evaporation of the Pleistocene-era Lake
The Many Uses of Salt
Our oceans are the greatest single source of salt.
Bonneville, around 12,500 years ago. Scientists estimate the lake was as large as present-day Lake Michigan and a thousand feet deep at its peak. The greatest natural source of salt, however, is the ocean itself. The ocean covers 70 percent of our planet. In fact, 97 percent of the earth’s water is salty. It has been estimated that if we were to extract all the salt from the ocean and pile it on the earth’s surface, it would create a layer over 500 feet thick—that’s the height of a skyscraper! All this salt gets into the ocean through the action of rain. As rain falls on land, it washes over rocks. Acids in the rain break down, or erode, the rocks. This creates the charged atomic particles known as ions. The ions flow with the rain down into streams and rivers and out into the sea. Sodium and chloride account for 90 percent of the ions in the ocean, and together they form salt. The salt stays in the ocean because when the water evaporates, it leaves the salt behind.
Although we’re most familiar with pickled cucumbers, just about any vegetable can be pickled, including carrots, green beans, peppers, onions, and many others.
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