food and nutrients

lipids

Lipids are nutrients such as fats. They are used for energy and other important purposes. One gram of lipids provides the body with 9 Calories of energy, more than twice as much as carbohydrates or proteins. Lipids also make up cell membranes, protect nerves, control blood pressure, and help blood clot. You must consume some lipids for these purposes. Good food sources of lipids are shown in Figure 17.4. Any extra lipids you consume are stored as fat. A certain amount of stored fat is needed to cushion and protect internal organs and insulate the body. However, too much stored fat can lead to obesity and cause significant health problems. A type of lipid called trans fat is found in many processed foods. Trans fat is rare in nature but is manufactured and added to foods to preserve freshness. Eating foods that contain trans fat increases the risk of heart disease. Trans fat may be found in such foods as cookies, doughnuts, crackers, fried foods, ground beef, and margarine.

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proteins

Proteins are nutrients made up of smaller molecules called amino acids. The digestive system breaks down proteins in food to amino acids, which are used for protein synthesis. Proteins synthesized from the amino acids in food serve many vital functions. They make up muscles, control body processes, fight infections, and carry substances in the blood. If you eat more protein than you need for these functions, the extra protein is used for energy. One gram of protein provides 4 Calories of energy, the same as carbohydrates. A 13-year-old needs to eat about 34 grams of protein a day. Figure 17.3 shows good food sources of protein.

what are nutrients

There are a variety of substances in foods that the body needs. Any substance in food that the body needs is called a nutrient. There are six major types of nutrients: carbohydrates, proteins, lipids, water, minerals, and vitamins. Carbohydrates, proteins, and lipids can be used for energy. Proteins also provide building materials. Proteins, minerals, and vitamins help control body processes. Water is needed by all cells just to stay alive. The six types of nutrients can be divided into two major categories based on how much of them the body needs. The categories are macronutrients and micronutrients.

why your body needs food

Your body needs food for three purposes: 1. Food gives the body energy. You need energy for everything you do. The energy in food is measured in a unit called the Calorie. 2. Food provides building materials for the body. The body needs building materials for growth and repair. 3. Food contains substances that help control body processes. Body processes must be kept in balance for good health.

carbohydrates

Carbohydrates include sugars, starches, and fiber. Sugars and starches are used by the body for energy. One gram of sugar or starch provides 4 Calories of energy. Fiber doesnt provide energy, but it is needed for other uses. At age 13 years, you need about 130 grams of carbohydrates a day. Figure 17.2 shows good food sources of each type. Sugars are small, simple carbohydrates. They are found in foods such as milk and fruit. Sugars in foods such as these are broken down by your digestive system to glucose, the simplest of all sugars. Glucose is taken up by cells for energy. Starches are larger, complex carbohydrates. They are found in foods such as grains and vegetables. Starches are broken down by your digestive system to glucose, which is used for energy. Fiber is a complex carbohydrate that consists mainly of cellulose and comes only from plants. High-fiber foods include whole grains and legumes such as beans. Fiber cant be broken down by the digestive system, but it plays important roles in the body. It helps keep sugar and lipids at normal levels in the blood. It also helps keep food waste moist so it can pass easily out of the body.

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macronutrients

Macronutrients are nutrients the body needs in relatively large amounts. They include carbohydrates, proteins, lipids, and water.

water

Water is essential to life because chemical reactions within cells take place in water. Most people can survive only a few days without consuming water to replace their water losses. How do you lose water? You lose water in your breath each time you exhale. You lose water in urine. You lose water in sweat, especially if you are active in warm weather. The boy in Figure 17.5 is taking a water break while playing outside on a hot day. If he doesnt take in enough water to replace the water lost in sweat, he may become dehydrated. Symptoms of dehydration include dry mouth, headache, and dizziness. Dehydration can be very serious. It can even cause death.

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micronutrients

Micronutrients are nutrients the body needs in relatively small amounts. They include minerals and vitamins. These nutrients dont provide the body with energy, but they are still essential for good health.

minerals

Minerals are chemical elements that dont come from living things or include the element carbon. Many minerals are needed in the diet for normal functioning of the body. Several minerals that are needed in relatively large amounts are listed in Table 17.1. As you can see from these examples, minerals have a diversity of important functions. Your body cant produce any of the minerals it needs, so you must get them from the food you eat. The table shows good food sources of the minerals. Mineral Calcium Chloride Magnesium Phosphorus Potassium Sodium Function strong bones and teeth salt-water balance strong bones strong bones and teeth muscle and nerve functions muscle and nerve functions Good Food Sources milk, green leafy vegetables table salt, most packaged foods whole grains, nuts poultry, whole grains meat, bananas table salt, most packaged foods Not getting enough minerals can cause health problems. For example, not getting enough calcium may cause osteoporosis. This is a disease in which the bones become porous so they break easily. Getting too much of some minerals can also cause health problems. Many people get too much sodium. Sodium is added to most packaged foods. People often add more sodium to their food by using table salt. Too much sodium has been linked to high blood pressure in some people.

vitamins

The vitamins to watch out for are A, D, E, and K. These vitamins are stored by the body, so they can build up to high levels.

instructional diagrams

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questions

The six major types of nutrients include

a. starches.

b. amino acids.

-->  c. lipids.

d. all of the above

__state in which the body does not contain enough water

a. trans fat

b. macronutrient

c. carbohydrate

-->  d. dehydration

e. protein

f. micronutrient

g. mineral

__any nutrient the body needs in relatively small amounts

a. trans fat

b. macronutrient

c. carbohydrate

d. dehydration

e. protein

-->  f. micronutrient

g. mineral

Macronutrients include all of the following except

a. carbohydrates.

b. water.

c. proteins.

-->  d. vitamins.

The food we eat provides our body with

a. building materials.

b. energy.

c. nutrients.

-->  d. all of the above

__chemical element needed in small amounts for normal functioning of the body

a. trans fat

b. macronutrient

c. carbohydrate

d. dehydration

e. protein

f. micronutrient

-->  g. mineral

__artificial lipid added to foods to preserve freshness

-->  a. trans fat

b. macronutrient

c. carbohydrate

d. dehydration

e. protein

f. micronutrient

g. mineral

Which type of food is a good source of sugar?

-->  a. milk

b. fish

c. beans

d. meat

__any nutrient the body needs in relatively large amounts

a. trans fat

-->  b. macronutrient

c. carbohydrate

d. dehydration

e. protein

f. micronutrient

g. mineral

The body needs lipids for

-->  a. cell membranes.

b. muscles.

c. enzymes.

d. all of the above

__nutrient made up of amino acids

a. trans fat

b. macronutrient

c. carbohydrate

d. dehydration

-->  e. protein

f. micronutrient

g. mineral

__sugar, starch, or fiber

a. trans fat

b. macronutrient

-->  c. carbohydrate

d. dehydration

e. protein

f. micronutrient

g. mineral

All nutrients provide the body with energy.

a. true

-->  b. false

Your body cannot produce any of the vitamins it needs.

a. true

-->  b. false

The mineral sodium is needed for normal muscle function.

-->  a. true

b. false

Vitamin K is needed for normal nerve function.

a. true

-->  b. false

Proteins can provide the body with energy.

-->  a. true

b. false

Your body needs food for

a. energy.

b. growth and repair of body tissues.

c. control of body processes.

-->  d. all of the above

There are six major types of nutrients. One of the six types is

-->  a. water.

b. trans fat.

c. glucose.

d. fiber.

Micronutrients include

a. starches.

-->  b. minerals.

c. fiber.

d. proteins.

Roles of proteins in the body include

a. making up cell membranes.

b. helping blood clot.

c. keeping bones strong.

-->  d. fighting infections.

How many Calories are provided by one gram of lipids?

a. 4

b. 5

c. 8

-->  d. 9

Vitamins made by bacteria in the gut include vitamin

a. A.

-->  b. B12 .

c. D.

d. two of the above

All of the following types of nutrients can be used for energy except

-->  a. vitamins.

b. proteins.

c. carbohydrates.

d. lipids.

All carbohydrates provide the body with energy.

a. true

-->  b. false

Fiber helps keep sugar and lipids at normal levels in the blood.

-->  a. true

b. false

Carbohydrates and proteins provide 4 Calories of energy per gram.

-->  a. true

b. false

Eating trans fats can increase the risk of heart disease.

-->  a. true

b. false

Your body can produce some of the minerals it needs.

a. true

-->  b. false

Potassium is needed for strong bones and teeth.

a. true

-->  b. false

Vitamin B12 is needed for normal nerve function.

-->  a. true

b. false

diagram questions

No diagram questions associated with this lesson