Nutrition is the process of taking in food and using it for energy, growth and repair. A balanced diet contains all nutrients in the right amounts and is an important exam topic.
Main Nutrients
- Carbohydrates: main source of energy (rice, wheat, sugar).
- Proteins: build and repair the body (pulses, eggs, milk).
- Fats: store energy (oil, butter, nuts).
- Vitamins and minerals: protective nutrients.
- Water and roughage: needed for body functions.
Energy Value of Food
- 1 gram of carbohydrate gives about 4 kcal.
- 1 gram of protein gives about 4 kcal.
- 1 gram of fat gives about 9 kcal.
Important Minerals
- Calcium: for bones and teeth.
- Iron: for haemoglobin in blood.
- Iodine: for the thyroid gland.
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Deficiency Problems
Lack of protein causes kwashiorkor and marasmus in children. Lack of iron causes anaemia. Lack of iodine causes goitre. Lack of calcium weakens bones.
Important Facts
Proteins are called body-building foods. Roughage (fibre) does not give energy but helps digestion. A balanced diet must include water and fibre, not just energy-giving foods.
Quick Revision Points
- Carbohydrates are the main energy source.
- Proteins build and repair the body.
- Fat gives 9 kcal/gram, the highest energy.
- Iron deficiency causes anaemia.
- Iodine deficiency causes goitre.
- Protein deficiency causes kwashiorkor.
- Roughage helps digestion.