Protein Flashcards
Types and Structure: High Biological Value (HBV) and Low Biological Value (LBV) Proteins
Proteins are made up of amino acids, which are essential for the body’s growth and repair. Some amino acids are essential amino acids, meaning the body cannot produce them and must obtain them from food.
• High Biological Value (HBV) Proteins: Contain all the essential amino acids the body needs.
• Sources: Mainly from animal products, such as meat, fish, eggs, dairy, and also soya and quinoa (plant-based exceptions).
• Low Biological Value (LBV) Proteins: Lack one or more essential amino acids.
• Sources: Mainly from plant-based foods, such as cereals, pulses, nuts, and seeds.
To obtain all essential amino acids from LBV proteins, protein complementation can be used (e.g., eating beans with rice).
Functions of Protein
Protein is essential for:
1. Growth and repair – Needed for cell and muscle development.
2. Maintenance – Keeps body tissues healthy and replaces old cells.
3. Energy source – If carbohydrate and fat intake is low, the body uses protein for energy.
4. Production of enzymes and hormones – Important for digestion and bodily functions.
Protein Deficiency
A lack of protein can lead to:
• Poor growth (especially in children).
• Weakened immune system, leading to frequent infections.
• Hair loss and brittle nails.
• Muscle loss and weakness.
• Oedema (swelling due to fluid retention).
• Kwashiorkor, a severe protein deficiency disease causing a swollen abdomen.
Animal and Vegetable Sources of Protein
Animal-Based Protein Sources (HBV):
• Meat (beef, chicken, pork, lamb)
• Fish (white fish, oily fish, shellfish)
• Eggs
• Dairy products (milk, cheese, yogurt)
Plant-Based Protein Sources (LBV):
• Pulses (lentils, beans, chickpeas)
• Nuts and seeds
• Grains (rice, wheat, oats)
• Soya products (tofu, soya milk – HBV exception)
• Quinoa (HBV exception)
Vegetarians and vegans must ensure they eat a variety of LBV protein sources or include HBV plant sources like soya and quinoa.
