The Digestive System Food and Energy
Chapter 15-section 1
Key Concepts Why does your body need food?
How do the six nutrients needed by the body help carry out essential processes? How can the Food Guide Pyramid and food labels help you have a healthy diet?
Key Terms Nutrient Calorie Carbohydrate Glucose Fat Protein Amino acid
Vitamin Mineral Food guide pyramid Percent daily value Dietary reference intakes (DRI’s)
Why you need food Food provides your body with materials for growing and for repairing tissue Food also provides energy for everything you do Ex-running, reading, sleeping, Food also helps your body maintain homeostasis
Nutrients Your body breaks down the foods you eat into nutrients
There are six groups of nutrients necessary for human health Carbohydrates, fats, proteins, vitamins, minerals, and water
Energy When nutrients are used by the body for energy, the amount of energy they release can be measured in units called calories Calorie with a C is used to measure the energy in foods You need to eat a certain number of calories each day to meet your body’s energy needs Your daily energy requirement depends on your level of physical activity, the more active you are the greater your energy needs are
Carbohydrates They are composed of carbon, oxygen, and hydrogen and are a major source of energy One gram of carbohydrate provides your body with four Calories of energy Carbohydrates provide the raw materials to make cell parts. They are divided into simple carbohydrates and complex carbohydrates
Simple carbohydrates These carbohydrates are known as sugar and provide quick energy for the body
Complex carbohydrates are made up of many sugar molecules lined together in a chain Starch is a complex carbohydrate found in foods from plants such as potatoes, rice, wheat, corn Fiber is a complex carbohydrate but unlike starch fiber cannot be broken down into sugar molecules, instead fiber passes through the body and is eliminated Fiber helps keep the digestive system functioning properly
Fats Fats contain more than twice the energy of an equal amount of carbohydrates Fats form part of the cell membrane, the structure that forms the boundary of a cell Fatty tissue protects and supports your internal organs and insulates your body
Kinds of fats saturated and unsaturated
Unsaturated fats are usually liquid at room temperature-olive oil Saturated fats are usually solid at room temperature-Crisco Trans fats help keep food fresher longer and are considered to be less healthful than unsaturated fats
Cholesterol Waxy, fatlike substance found only in animal products
Your liver can make all of the cholesterol your body needs and is not a necessary part of the diet
Proteins Are needed for tissue growth and repair
They also play an important part in chemical reactions within cells 10-35 percent of your daily Calorie intake should come from proteins
Amino Acids Proteins are made up of small units called amino acids which are linked together chemically to form large protein molecules
Complete and Incomplete Proteins
Complete proteins-meat and eggs, these foods contain all the essential amino acids Incomplete proteins-come from plant sources such as beans, grains and nuts. They are incomplete because they are missing one or more essential amino acid
Vitamins and Minerals Unlike other nutrients V & M do not provide the body with energy or raw materials Instead they help the body carry out various processes Vitamins act as helper molecules in a variety of chemical reactions- Ex – Vitamin K helps blood to clot Vitamin D can be made when your skin is exposed to sunlight
Fat Soluble and Water Soluble Vitamins
Fat soluble vitamins dissolve in fat and they are stored in fatty tissues in the body Vitamins A, D, E, and K are all fat soluble vitamins Water-soluble vitamins dissolve in water and are not stored in the body Vitamins- C and D are water soluble vitamins
Importance of Vitamins
Vitamins are only needed in small amounts A lack of certain vitamins in the diet can lead to health problems
Importance of Minerals
Minerals are present in soil and are absorbed by plants through their roots Minerals are obtained by eating plant foods or animals that have eaten plants Ex. Calcium-strong bones and teeth Iron is needed for the proper functioning of red blood cells
Vitamins and Minerals Are needed by your body in small amounts to carry out chemical processes
Water Water is the most abundant substance in the body
It accounts for 65 percent of the average person’s body weight People cannot survive without fresh water
Where do the body’s vital processes take place?
Water The body’s vital processes including chemical reactions such as the break down of nutrients take place in water Cells in your body are mostly composed of water
(2) Nutrients and other important substances are carried throughout the body dissolved in the watery part of the blood Water in blood also carries waste materials that must be removed from your body Perspiration consists of chemicals dissolved in water,comes from body tissue, and helps regulate body temperature by cooling the body
The Food Guide Pyramid
Food Guide Pyramid Classifies foods into six groups
Indicates how many servings from each group should be eaten everyday to maintain a healthy diet
1. What are some reasons that your body needs food?
Feel your best, perform well in school and sports, reduce your risk of illness
2. How are fats beneficial
They provide energy form part of cell membranes, protect and support internal organs, insulate your body
3. Are vitamins and minerals sources of energy
4. Why is it important to get vitamins and minerals from food?
The body cannot make minerals and some vitamins
5. To obtain enough calcium what foods should people eat if they do not drink milk?
Cheese, dark green leafy vegetables
6. What does the body use calcium for?
Building bones and teeth, clotting blood and nerve and muscle function
7. How does water work with vitamins and minerals to carry out body processes?
Vitamins and minerals help carry out chemical reactions which take place in water
8. Why are the food groups shaped like a pyramid
The wider base indicates that the greatest portion of persons diet should be from this group
9. Name two ways in which foods are used by the body?
Growing, repairing tissues, providing energy, maintaining homeostasis
10. What is a calorie? The amount of energy needed to raise the temperature of one gram of water by one degree Celsius, the more Calories a food has the more energy it contains
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