Nutrition and nutrients

Nutrients are substances in food that the body needs for energy, growth, repair and protection.

The nutrients

• Carbohydrates (maize meal, rice, bread, potatoes): main energy source.
• Proteins (beans, groundnuts, eggs, meat, fish, matemba, milk): growth and repair. Animal proteins have all essential amino acids; plant proteins are combined (sadza with beans) to complement each other.
• Fats and oils (cooking oil, butter, nuts): concentrated energy, insulation, carry vitamins A, D, E and K.
• Vitamins: A (eyesight – carrots, pumpkin, green leaves), B group (energy release – whole grains), C (healthy skin and gums, iron absorption – oranges, guavas, tomatoes), D (strong bones – sunlight, eggs).
• Minerals: iron (blood – liver, green vegetables), calcium (bones and teeth – milk, small fish), iodine (thyroid – iodised salt).
• Water and dietary fibre: digestion and preventing constipation.

Deficiency diseases

Kwashiorkor (protein), marasmus (energy and protein), scurvy (vitamin C), rickets (vitamin D/calcium), anaemia (iron), goitre (iodine).

Energy balance

Energy in (food) should match energy used (activity). Too much leads to obesity; too little leads to weight loss.

Check yourself

1. Name two sources of protein suitable for a low-income family.
2. Which vitamin helps the body absorb iron?
3. Name the deficiency disease caused by lack of iodine.