IGCSE Biology Human Nutrition

Summary:

Human nutrition is essential for providing energy, materials for growth and repair, and to support our overall health. A balanced diet ensures that we receive the necessary nutrients in the right proportions to keep our bodies healthy. Nutrients are substances vital for life and growth, including carbohydrates (e.g., starch and sugars), proteins (composed of amino acids), and fats (formed from glycerol and fatty acids). Saturated fats and cholesterol, found in meat, are linked to heart disease.

A balanced diet should contain five essential nutrients: carbohydrates, proteins, fats, vitamins, and minerals. The energy content of food is measured in kilojoules (kJ) or kilocalories. Food labels provide information on nutrient content per 100g of food. Different foods contain varying amounts of energy, with high-fat foods generally having higher energy content.

The energy required depends on age, body size, activity levels, and pregnancy. Water has a specific heat capacity, and its energy can be calculated using the formula: Energy = mass x specific heat capacity x temperature change.

Deficiencies in specific vitamins or minerals can lead to deficiency diseases. Vitamins and minerals have unique roles in the body, including vitamins A, C, and D, and minerals calcium and iron. Ensuring a balanced diet with sufficient nutrients is crucial for maintaining good health.

Excerpt:

IGCSE Biology Human Nutrition

Human Nutrition:
The food that we eat is called our diet. We need food for 3 reasons:
– To provide us with a ‘fuel’ for energy
– To provide materials for growth and repair
– To help fight disease and keep our bodies healthy.

A balanced diet is a diet that provides enough of the substances we need in the correct proportions to keep us healthy. A nutrient is a substance that provides nourishment essential for maintaining life and growth.

Starch is a carbohydrate, a long, insoluble molecule made of repeating glucose units (Oxygen, carbon, and hydrogen).

Sugars are also carbohydrates but smaller, soluble molecules found in sweet-tasting foods (Containing oxygen, carbon, and hydrogen).

Proteins are polymers, made of subunits called amino acids. There are 20 different amino acids in the body.