78 Unit 2 Nutrition and Food Choices Copyright Goodheart-Willcox Co., Inc. Water Water is necessary for most bodily functions. In fact, although people can live for several weeks, and even months, without taking in any other type of nutrients, they can survive only a few days without water. Water helps your body in a number of ways, including • maintaining a normal temperature • cushioning and lubricating your joints • protecting your spinal cord and other sensitive tissues • getting rid of wastes (through urination, perspiration, and bowel movements) and • moving oxygen, nutrients, wastes, and other materials throughout the body. Because your body loses water every day through urination, sweat, and even exhaling breath, you need to ingest water to replace what your body loses and prevent dehydration. Dehydration Dehydration is a dangerous condition in which the body’s Jessica is 15 years old and a sophomore in high school. She is very busy with many activities— performing in the choir, volunteering with Big Brothers/Big Sisters, and playing on the junior varsity softball team. She often fi nds herself eating in the car as she races from one activity to another. Because Jessica is a vegetarian, she typically eats lots of carbohydrates (such as breads and pasta), vegetables, and fruits. Over the last few months, Jessica has found herself feeling very tired and out of breath during softball practice. She even fi nds herself struggling to climb a fl ight of stairs. She is also having regular headaches. Jessica’s parents took her to the doctor to fi gure out what was causing her to feel so tired. Blood work revealed that Jessica is showing signs of anemia, which is caused by a defi ciency of iron in her blood. She is now making changes to her diet in an effort to take in more iron in the foods she eats. Jessica is also taking an iron supplement. Thinking Critically 1. What do you think are the primary factors that led Jessica to become anemic? CASE STUDY Why Is Jessica Weak and Tired? 2. What are some strategies that you think could help Jessica eat more nutritious foods, including more foods that are high in iron? 3. What advice would you give other teenag- ers who fi nd themselves in the same situ- ation as Jessica to help prevent them from adopting unhealthy eating habits? dehydration a condition in which the body’s tissues lose too much water