Lesson 7.1 Getting Enough Nutrients

Types of Nutrients 📷

While it is enjoyable to eat a good meal or a , food has a more fundamental role in people’s lives. Food is the fuel that powers people’s bodies. Food contains nutrients, which are that give your body what it needs to grow and function properly. There are six general types of nutrients (Figure 7.1).

Some of these nutrients provide the energy your body needs to perform daily physical activities, such as and riding a bicycle. Your body also uses this energy to perform many important functions that go on within your body. For instance, your body has to maintain a stable . It needs to provide energy to the brain and nervous system. It also needs energy to build body tissues.

Other make it possible for your body to perform certain important functions. For example, your body needs vitamins and minerals to build new cells, strengthen bones, and through your blood. Nutrients also regulate basic processes in your body, such as breathing.Your body requires some nutrients in large amounts, and these are called macronutrients. include carbohydrates, proteins, and fats. Other nutrients, called , are needed in smaller amounts. Vitamins and minerals are .

Nutrition can improve your quality of life and help prevent disease. Food choices you make change levels of particular in the brain that directly influence your mental and emotional health. Eating nutritious foods can also lead to social benefits. These foods increase energy and . This can help you enjoy spending time with friends and family members.

Carbohydrates

, a major source of , are found in fruits, vegetables, grains, and milk products. Carbohydrates are sugars and starches, and are either simple or complex (Figure 7.2).

Sugars are . These simple sugars occur naturally in some foods, including fruits and dairy products. Starches are . Products made from grains, such as bread, cereal, rice, and pasta, are rich sources of starch. Starch is also found in beans and in some types of vegetables, including potatoes, peas, and corn.

Dietary fiber is a tough that the body is unable to wholly digest. This type of carbohydrate is found only in plant-based foods. Rich sources of dietary fiber include fruits, , whole grains (such as whole-wheat bread or brown rice), and nuts.

Dietary fiber does not provide the body with energy. Still, it does have important health benefits, such as the following:

• . Fiber attaches to cholesterol and carries it out of the body during digestion. Cholesterol is a type of fat made by the body that is also present in some foods. Having elevated levels of cholesterol in the body increases a person’s risk of developing heart disease, high blood pressure, and stroke. A diet that includes enough dietary fiber can reduce the risk of these conditions (Figure 7.3).

• . Glucose is the body’s preferred source of energy and powers the brain. Glucose enables you to concentrate and pay attention in class. By balancing the level of glucose in the blood, fiber can help control some types of diabetes.

• . Fiber helps the digestive system work properly by adding bulk to feces. This can help prevent conditions such as constipation (hard feces) and hemorrhoids. Hemorrhoids are swollen veins in the rectum that are caused by straining the muscles to pass hard feces. The condition can be painful.

• . High-fiber foods take longer to chew than many other types of foods. As a result, people eating a high-fiber meal are inclined to eat less than they would otherwise. Fiber also slows the movement of food out of the stomach and into the intestines. This prevents becoming hungry again soon after eating.

Proteins

is a nutrient the body uses to build and maintain all of its cells and tissues. Protein plays a very important role in the body (Figure 7.4).

Your body uses up and every day through many regular activities. For example, when you shower and brush your hair, you are actually losing protein. The shower washes some skin cells off your body. Some hair remains in the brush. Those and that hair contain protein.

Since you , you need to take in protein to replace it every day. Fortunately, in the United States, many foods that people eat on a regular basis contain protein. In fact, most people eat more than they need.

People who do not consume enough protein risk . For example, the cells that help the body fight disease are made of protein. People who do not get enough protein are more likely to have systems. This means they have an increased risk of developing .

Types of Proteins

All proteins are made up of called amino acids. Twenty different amino acids join in various combinations to make all types of proteins. The body produces some of these amino acids, which are called . Other amino acids, however, are not produced by the body in or at all. You can only get them by eating particular foods. This type of amino acid is called an acid because it is essential that your diet includes it. Proteins are divided into two types, depending on whether they include all of the (Figure 7.5).

Proteins and Vegetarians

Some avoid eating all (or most) foods from animal sources. This means they must rely on proteins to meet their needs (Figure 7.6). People who eat a vegetarian diet simply have to combine different types of foods that can work together to provide all of the acids. For example, rice contains essential amino acids that are lacking in red beans and red beans contain essential amino acids lacking in rice. When both rice and beans are eaten, all the are provided.

Fats Fats are a type of nutrient largely made up of , which provide a valuable source of energy. Fatty acids are an important source of energy for muscles. Common fats in the diet include , , and .

Types of Fats Saturated fats are found primarily in , such as meat and dairy products. Saturated fats are typically solid at room temperature.

Unsaturated fats are found in , such as vegetable oils, some peanut butters and margarines, olives, salad dressing, nuts, and seeds. Unsaturated fats are liquid at room temperature.

Trans fats used to be found in many processed foods, such as packaged cookies, chips, , and crackers. Some trans fats occur naturally and are found in foods from animals, such as cows and goats.

Your body stores excess calories you eat as body fat. Despite the negative publicity that body fat gets, it is important to your . Body fat has important functions, such as the following:

• to the body when food is unavailable

• act as a cushion to protect internal organs

• provide a layer of insulation to help maintain your so you do not get too hot or too cold

Fats in the Diet

Although are important for the body to function, some fats may be better for you than other fats. tend to be associated with higher levels of cholesterol in the blood. Diets that are high in saturated fats may lead to long-term health conditions (Figure 7.7). These conditions may include , , some types of , and diabetes.

Some scientists believe trans fats pose major as well. Many cities and states have passed laws that require restaurants to limit how much trans fat they use. In 2015, the United States Food and Drug Administration declared that trans fats were not “generally recognized as safe.” The FDA gave food companies three years to remove from their food products.

are organic substances that come from that are necessary for normal growth and development. Different vitamins have different functions in the body.

Your body requires . Because your body cannot create these vitamins, you need to absorb them from the foods you eat. Unlike , your body requires only very small amounts of vitamins to function properly. Eating a balanced diet that contains a variety of foods can easily provide you with the vitamins you need.

Vitamins can be divided into two distinct types— and (Figure 7.8). Water-soluble vitamins dissolve in water. They pass into the during digestion and are either used immediately by the body or are removed by the kidneys during . The nine water-soluble vitamins are vitamin C and the B vitamins.

vitamins are absorbed along with dietary fat and dissolve in the body’s fats. They are stored in the body for later use. There are four fat-soluble vitamins—vitamins A, D, E, and K.

Minerals

are inorganic elements that are found in soil and water. Minerals are from the soil and water. You then absorb minerals from the plants you eat, the water you drink, or from animal food sources that have absorbed the minerals. Your body in small amounts to grow and develop normally.

As with , each mineral helps with different body processes (Figure 7.9). Eating a diet generally provides all of the minerals your body needs. Two very important minerals are . The body needs iron so that blood cells can throughout the body. It needs calcium to build . The recommended dietary allowance (RDA) for calcium in teens is 1,300 milligrams (mg). The RDA for iron depends on age and biological sex. For people ages 9 to 13, the RDA for iron is 8mg. Between 14 and 18 years of age, the RDA for males is 11mg and the RDA for females is 15mg.

Water

is necessary for the body to work properly and remain healthy. In fact, although people can live for several weeks, and even months, without taking in food, they can survive only a water.

Your body every day through urination, sweat, and exhalation. For this reason, you need to take in water to replace what your body loses to . condition in which the body’s tissues lose too much water.

People should drink 8½ to 11½ cups of fluids per day to have enough water in the body. Normally, most people can be sure to have in their body simply by drinking when they are thirsty (Figure 7.10).