Human Nutrition ( 1 )

• Nutrients essential for humans

  • Carbohydrates
  • Fats and oils
  • Proteins
  • Vitamin C
  • Vitamin D
  • Mineral ions (e.g. calcium, iron)
  • Fiber
  • Water
• Carbohydrates


  Provide energy for respiration in cells
• Examples of carbohydrates


  • Rice
  • Pasta
  • Potatoes
• Fats


  • Used as long-term stores of energy
  • Provide insulation under the skin
• Examples of fats


  • Cheese
  • Fatty meats
  • Butter
• Proteins


  Vital substance for growth and repair of tissues
• Foods containing proteins


  • Fish
  • Meat
  • Eggs
• Vitamin C


  • Maintains healthy skin and gums
  • Deficiency causes scurvy
• Foods containing vitamin C

  • Citrus fruits (e.g. oranges, lemons)
• Vitamin D


  • Helps the body absorb calcium
  • Deficiency leads to rickets
• Mineral ions (e.g. calcium, iron)


  Essential for human nutrition
• Calcium


  • Needed for strong and healthy bones and teeth
  • Plays a role in blood clotting
• Foods rich in calcium

  • Milk
  • Cheese
  • Eggs
• Iron


  Needed to make hemoglobin which carries oxygen in red blood cells
• Fiber/Roughage


  Helps food move through the stomach and intestines
• Foods containing fiber


  • Vegetables
  • Fruits
  • Whole grains
• Water


  Needed for chemical reactions in cells
• Water can be obtained from both drinks and food
• Digestive system


  Breaks down large insoluble molecules into smaller soluble food molecules to provide the body with nutrients
• Parts of the digestive system

  • Mouth
  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
• Associated organs of the digestive system

  • Salivary glands
  • Pancreas
  • Liver
  • Gall bladder
• Parts of the small and large intestines

  • Duodenum (first part of small intestine)
  • Ilium (second part of small intestine)
  • Colon (larger part of large intestine)
  • Rectum
  • Anus
• Functions of the digestive system

  • Ingestion (taking substances into the body)
  • Digestion (breakdown of food)
  • Absorption (movement of nutrients into the blood)
  • Assimilation (uptake and use of nutrients by cells)
  • Ejection (removal of undigested food as feces)
• Types of digestion


  • Physical digestion (breakdown of food into smaller pieces without chemical change)
  • Chemical digestion (breakdown of food molecules by enzymes)
• Physical digestion processes


  • Chewing by teeth
  • Liquefying in the stomach
  • Emulsification by bile
• Types of teeth


  • Incisors
  • Canines
  • Premolars
  • Molars
• Incisors


  For biting and cutting
• Canines


  For tearing, holding and biting
• Premolars and molars


  For chewing and grinding
• Parts of a tooth

  • Enamel
  • Dentine
  • Pulp cavity
  • Nerves
  • Blood vessels
  • Cement
• Bile


  • Greenish-brown fluid produced by the liver and stored in the gall bladder
  • Helps in physical digestion by emulsifying fats
  • Helps in chemical digestion by neutralizing stomach acid