Macronutrients: protein

Macronutrients: protein

Overview of Protein

  • Protein is one of the three essential macronutrients, alongside carbohydrates and fats.
  • It is composed of smaller units known as amino acids
  • There are around 20 different amino acids used by the human body, 8 of which cannot be produced by the body and must be obtained from the diet - these are known as essential amino acids.

Functions of Protein

  • Protein is responsible for growth and repair of body tissues.
  • It is essential for the production of enzymes, which aid in food digestion and other chemical reactions in the body.
  • Protein plays a crucial role in immune function, as it helps to produce antibodies and other immune cells.
  • It also provides a source of energy, supplying 4 kilocalories of energy per gramme.

Dietary Sources of Protein

  • Protein can be found in a variety of both animal and plant-based foods.
  • Animal sources of protein include meat, eggs and dairy products, which contain all essential amino acids.
  • Plant sources of protein include beans, lentils, nuts and whole grains, which often lack one or more essential amino acid, but can be consumed in combinations to fulfil protein needs.

Recommended Intake of Protein

  • The Reference Intake (RI) for protein for adults is 50g a day but the actual needed amount depends on body weight, age, gender and activity level.

Protein Malnutrition

  • Insufficient intake of protein can lead to Protein Energy Malnutrition (PEM) or Kwashiorkor, characterised by growth retardation, loss of muscle mass, decreased immunity, and deterioration of organ function.
  • Overconsumption of protein, primarily through supplements, can impose a burden on kidneys and may lead to long-term health problems.