IGCSE Biology 0610

7.1 Human nutrition – diet

This section describes the dietary importance of the main food groups, water, and dietary fibre for human health.

Main Food Groups

A balanced diet includes foods from all the main food groups. Each group provides different nutrients essential for growth, development, and maintaining health.

• Carbohydrates: The main source of energy for the body. They are broken down into glucose.
• Proteins: Essential for growth, repair, and maintenance of body tissues. They are made up of amino acids.
• Fats: Provide energy, insulation, and help absorb some vitamins.
• Vitamins: Organic compounds needed in small amounts for various bodily functions.
• Minerals: Inorganic substances needed for various bodily functions, including bone health and nerve function.
• Water: Essential for all bodily processes.
• Dietary Fibre: Important for digestive health.

Dietary Importance of Each Food Group

The following table summarizes the key dietary importance of each food group:

Food Group	Main Nutrients	Dietary Importance
Carbohydrates	Glucose, Starch	Primary source of energy for the body. Important for brain function and physical activity.
Proteins	Amino Acids	Essential for growth, repair of tissues, and making enzymes and hormones.
Fats	Triglycerides, Fatty acids	Provide energy, insulation, protect organs, and help absorb fat-soluble vitamins (A, D, E, K).
Vitamins	Various (e.g., Vitamin A, Vitamin C, Vitamin D)	Essential for various bodily functions, including immune system support, vision, and bone health.
Minerals	Various (e.g., Calcium, Iron, Potassium)	Important for bone health, nerve function, blood formation, and fluid balance.
Water	None (essential component)	Essential for all bodily processes, including temperature regulation, transport of nutrients, and waste removal.
Dietary Fibre	Complex carbohydrates	Promotes healthy digestion, prevents constipation, and helps regulate blood sugar levels.

Water

Water is crucial for many bodily functions. It helps regulate body temperature through sweating, transports nutrients and waste products, and is involved in chemical reactions.

Dietary Fibre

Dietary fibre is a type of carbohydrate that the body cannot digest. It is found in plant-based foods like fruits, vegetables, and whole grains.

There are two main types of dietary fibre:

• Soluble fibre: Dissolves in water to form a gel-like substance. Helps lower blood cholesterol levels and regulate blood sugar.
• Insoluble fibre: Does not dissolve in water. Adds bulk to the stool and helps prevent constipation.

A diet rich in dietary fibre is important for maintaining a healthy digestive system.