Food and Nutrition: Nutrients, Digestion and Meal Planning
Core concepts
Candidates must know the three energy-giving nutrients (carbohydrates, fats, proteins), the protective nutrients (vitamins and minerals), water and dietary fibre, and the main food sources of each. Learn the functions of protein (growth and repair), carbohydrates (energy, with starch and sugar distinguished), fats (energy, insulation, fat-soluble vitamin absorption) and the roles of iron, calcium, vitamin A, the B group, vitamin C and vitamin D. Understand deficiency diseases: kwashiorkor (protein deficiency), marasmus (energy deficiency), anaemia (iron), rickets (vitamin D and calcium), scurvy (vitamin C), night blindness (vitamin A) and goitre (iodine). Know the principles of a balanced diet, the effect of cooking on nutrients (water-soluble vitamins leach into cooking water; overheating destroys vitamin C), and food hygiene: personal cleanliness, safe storage, temperature control and prevention of cross-contamination.
Traps in questions
Do not confuse marasmus with kwashiorkor: kwashiorkor shows oedema and a swollen belly with some energy intake, while marasmus is severe wasting from overall lack of energy and protein. Do not say vitamins supply energy. Distinguish food groups from nutrients. When asked for a local meal, name specific dishes and state which nutrient each contributes.
Worked example
A question asks why a child eating only maize porridge may develop a deficiency. Rule of thumb: name the missing nutrient, the function it performs, and the resulting sign. Maize porridge is mainly starch, so it supplies energy but little complete protein; growth slows and oedema may appear, indicating kwashiorkor. Adding beans, groundnuts, eggs or milk supplies protein and improves the meal.