Protein

• Proteins are made up of small units called amino acids
• There are approximately 20 amino acids, some are made by the body when we eat protein, while others must be obtained from protein foods, known as essential amino acids
• Approximately 9 amino acids are essential and must be supplied by food, while non-essential amino acids can be made in the body
• Examples of proteins: Egg white (Albumen), Connective tissue (collagen, elastin), Bones (gelatin), Wheat (gluten)
• Functions of protein:

  • essential for growth
  • form part of body structure (skin, hair, muscles)
  • crucial for repair of body cells
  • forms hormones
• Complete proteins:

  • provide all the essential amino acids in the necessary proportions
  • also called high biological value proteins (HBV)
  • usually of animal origin (soya exception)
  • eg: meat, fish, egg, milk, cheese
• Incomplete proteins:

  • Low biological value (LBV)
  • lower quality
  • at least one limiting amino acid
  • usually vegetable origin
  • eg: pulses, cereals, nuts
• Protein in wheat is called gluten
• Complementary/Supplementary Action of protein:

  • when certain plant foods are eaten together to provide all the essential amino acids (eg: beans on toast)
• RDA: Recommended Daily Allowance

  • 1g protein for each kg of body weight
  • only 10% - 12% of Calories should come from protein                
• Too much protein can lead to:

  • high cholesterol
  • train on kidneys
  • Kwashiorkor - protein shortage
  • Marasmus - protein and calorie shortage
• Protein examples:

  • egg white - albumen
  • connective tissue - collagen, elastin
  • bones - gelatin
  • wheat - gluten