IGCSE Biology 0610
7.1 Diet
A balanced diet consists of all the necessary food groups in the correct proportions
| Food component | Importance | Principal dietary sources |
| Carbohydrates | Source of energy | Bread, cereals, pasta, rice, potatoes |
| Protein | Growth and repair (if not used for these, respired for energy) | Meat, fish, milk, nuts, eggs |
| Fats and oils | Insulation and long-term energy store | Butter, cheese, oil, fait in meat, nuts |
| Vitamin C | Tissue repair and disease resistance | Citrus fruits, strawberries, green veggies |
| Vitamin D | Helps to absorb calcium, strengthen bones and teeth | Fish oil, milk, butter, made by body when exposed to sunlight |
| Mineral ions – calcium | Strengthens bones and teeth, blood clotting | Milk, cheese, vegetables, fish |
| Mineral ions – iron | Used to make haemoglobin in red blood cells to transport oxygen | Liver, meat, leafy green vegetables |
| Fibre | Adds bulk for intestine to push against | Vegetables, whole grains |
| Water | Needed for chemical reactions to take place in cells | Water, juice, fruits and veggies |
Scurvy
Caused by vitamin C deficiency
Symptoms: Bleeding gums, tooth loss, limb pain
Rickets
Caused by vitamin D deficiency
Symptoms: Bone pain, soft weak bones, no bone growth