4.1 identify sources and describe functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, the mineral ions calcium and iron and water and dietary fibre as components of the diet

Balanced diet

A balanced diet should include the seven components: 

• carbohydrates: provides quick energy
• lipids: provides slow energy
• proteins: growth and repair, emergency energy source if diet has insufficient carbohydrates and fats
• water: important as a solvent, for breaking up large molecules by hydrolysis and carrying substances around your body
• fiber: to give muslces of the gut something to work on. It abosrbs a lot of water
• minerals and vitamins: needed in tiny amounts. If you do not get enough of them, you will suffer deficiency diseases as shown below

VITAMIN/MINERAL	FUNCTION IN BODY	GOOD FOOD SOURCE	DEFICIENCY DISEASE
Iron	Part of hemoglobin in red blood cells, helps carry oxygen	Red meat, liver, eggs, vegetables (spinach)
Calcium	Making teeth and bones	Dairy products, fish, bread, vegetables
Vitamin C	Sticks together cells lining surfaces such as mouth	Fresh fruit and vegetable	Scurvy
Vitamin A	Making a chemical in the retina, protects surface of eye	Carrots, fish liver oils, liver, butter, margarine	Night blindness, damaged cornea of eye
Vitamin D	Helps bones absorb calcium and phosphate	Fish liver oils	Rickets, poor teeth