CIE IGCSE Biology: 复习笔记:7.1.1 Diet & Deficiencies

CIE IGCSE Biology: 复习笔记:7.1.1 Diet & Deficiencies

Balanced Diet

  • A balanced diet consists of all of the food groups in the correct proportions
  • The necessary food groups are:
    • Carbohydrates
    • Proteins
    • Lipids
    • Vitamins
    • Minerals
    • Dietary Fibre
    • Water

Food Groups Table



Vitamin and Mineral Requirements Table



Varying Dietary Needs of Individuals Table


Scurvy & Rickets


  • Scurvy is the name for a severe vitamin C deficiency
    • It is caused by a lack of vitamin C in the diet for over 3 months
  • Its symptoms include:
    • Anemia
    • Exhaustion
    • Spontaneous bleeding
    • Pain in the limbs
    • Swelling
    • Gum ulcerations
    • Tooth loss
  • It is a condition that was commonly seen in sailors between the 15th to 18th centuries
    • Long sea voyages made it very hard to access a ready supply of fresh produce
  • Scurvy can be treated with oral or intravenous vitamin C supplements


  • Rickets is a condition in children characterised by poor bone development
  • Symtpoms include:
    • Bone pain
    • Lack of bone growth
    • Soft, weak bones (sometimes causing deformities)
  • Rickets is caused by a severe lack of vitamin D
    • Vitamin D is required for the absorption of calcium into the body
      • Calcium is a key component of bones and teeth
  • Vitamin D mostly comes from exposure to sunlight but it can also be found in some foods (fish, eggs and butter)
  • The treatment for rickets is to increase consumption of foods containing calcium and vitamin D
    • Alternatively vitamin D supplements can be prescribed