Chapter 4 - Food and digestion

There are five groups of food substances your diet should include:

• Carbohydrates
• Lipids
• Proteins
• Minerals
• Vitamins

Remember!! Have water and fibre in your diet!

Carbohydrates

Carbohydrates only make up 5% of the mass of the human body, but the have a very important role. They are the body's main 'fuel' for supplying cells with energy.

Lipids

Simply, these are fats and oils. They contains Carbon, Hydrogen and Oxygen. 

Proteins
Proteins are used mainly for growth and repair of cells.

Minerals
Like vitamins, mineral ions are only needed in small amounts to maintain a healthy body. A lack of the correct mineral ions in the diet also leads to deficiency symptoms.

Calcium

Calcium is needed to maintain healthy bones and teeth, for normal blood clotting and to control muscle contractions. Good sources of calcium include: cheese, eggs, leafy greens (e.g.:- broccoli, cabbage), milk. 

Iron

Iron is needed to produce haemoglobin, found in red blood cells.

Vitamins

Vitamin A

Maintains good vision

Strong immunity against infection

Healthy skin

Good sources of vitamin A include: milk, dairy products, mackerel and other oily fish.

Vitamin C

Vitamin C is also known as ascorbic acid and has several important functions.

For example, it:

• helps to protect cells and keeps them healthy
• is necessary for the maintenance of healthy connective tissue, which gives support and structure for other tissue and organs
• helps wound healing

A lack of vitamin C can lead to scurvy.

Vitamin D

The human body can make vitamin D when our skin is exposed to sunlight.

Good dietary sources of vitamin D include:

• margarine and breakfast cereals fortified with vitamin D
• oily fish
• eggs

Vitamin D is needed to maintain healthy bones and teeth. Vitamin D deficiency leads to rickets and bone pain.