Protein

Composition of Protein

• Protein is made up of four elements: Carbon (C)

Hydrogen (H)

Oxygen (O)

Nitrogen (N):

• Protein is the only nutrient that contains nitrogen, which is essential for the growth and repair of every cell in the body.

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Structure of Protein

• Proteins are composed of chains of smaller units called amino acids, linked together by peptide links.

  

• Enzymes break these peptide links during digestion, allowing the body to absorb and use the amino acids.

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Classification of Protein

High Biological Value (HBV) Proteins:

• Contain all the essential amino acids (EAA) the body needs but cannot produce.
• Found in animal sources, such as:
• Meat
• Fish
• Eggs
• Cheese
• Milk
• Yoghurt
• Soya beans
• Meat alternatives (e.g., textured vegetable protein, mycoprotein).

Low Biological Value (LBV) Proteins:

• Lack one or more essential amino acids. Known as non-essential amino acids (NEAA).
• Found in plant sources, such as:
• Peas
• Beans
• Lentils
• Nuts
• Cereals

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Reference Intake for Protein

• Adults: Need at least 50 g of protein daily, or 0.75 g per kilogram of body weight.
• Children and teenagers: Require more protein as they are growing rapidly.

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Functions of Protein

1. Growth and Repair:

• Necessary for the development and repair of body cells, including skin, blood, tissues, and bones.

2. Energy Source:

• Provides 4 kcal (17 kJ) of energy per gram.

3. Production of Substances:

• Supports the creation of enzymes, hormones, and antibodies that help fight diseases.

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Protein Deficiency Symptoms

• Poor or stunted growth with muscle wasting.
• Slow healing of wounds.
• Hair breakage and loss.
• Poor general health and immunity.
• Hormonal and enzyme imbalances.

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Key Takeaway

Protein is an essential macronutrient that supports growth, repair, and energy production. Consuming a variety of HBV and LBV protein sources ensures your body gets all the amino acids it needs to stay healthy and function optimally. A balanced intake of protein is crucial for people of all ages, especially children, teenagers, and individuals recovering from illness or injury.