Understanding the Importance of Food and Nutrition

Why Do We Need Food?

• Humans consume a balanced diet that contains a variety of different types of food, including carbohydrates, proteins, fats, vitamins, and minerals.
• The main nutrients needed by the body are:
  • Carbohydrates for energy
  • Proteins for growth and repair
  • Fats for energy storage
  • Vitamins and minerals for overall health

Food Types and Composition

• Carbohydrates:
  • Made of long chains of identical, small sugar molecules
  • The body breaks down long chains into smaller sugar molecules for energy
• Proteins:
  • Made of long chains of small, non-identical molecules (amino acids)
  • There are over 20 kinds of amino acids
  • Used for growth and repair
• Fats:
  • Made up of fat molecules containing fatty acids and glycerol
  • Used for energy storage and to make cell membranes

Releasing Energy from Food

• Problems with releasing energy from food:
  • Physical means cannot break down long chain molecules
  • Large food molecules are insoluble and cannot be dissolved in the blood
• The digestive system must cope with these problems to release energy

Digestive System

• An organ system made up of a group of organs working together
• Each organ has a specific function, and together they achieve digestion
• The digestive system is responsible for breaking down food into smaller, soluble molecules

What Happens to Food in the Body?

• Food is digested, which means it is broken down into smaller molecules
• Digestion occurs in two ways: physical/mechanical and chemical
• Physical digestion breaks down the physical shape of food, while chemical digestion breaks down chemical bonds

Chemical and Physical Digestion

• The body uses both physical and chemical digestion to break down food
• Physical digestion changes the shape of food to fit through the digestive system
• Chemical digestion breaks down chemical bonds to release useful chemicals and dissolve them in the blood

Digestive Tract

• The digestive system is a long tube (approximately 9m when stretched out) with an opening at each end
• The digestive tract includes the mouth, anus, gastrointestinal tract, liver, pancreas, and gallbladder
• The tube is extremely folded to fit inside the body and passes through various organs on its route from the mouth to the anus