Food, Nutrition and Health: Nutrients, Deficiencies and Diet-Health Links
Food, Nutrition and Health asks you to name nutrients, state what each does in the body, match deficiencies to their symptoms, and connect diet to health status. Board questions favour classification, function–source–deficiency tables and short definitions.
Nutrients by function
- Carbohydrates (4 kcal/g): cheapest energy source; excess is stored as fat. Cereals, roots, sugar.
- Proteins (4 kcal/g): growth, repair, enzymes, hormones, antibodies. Pulses, milk, egg, fish, meat, soy.
- Fats (9 kcal/g): concentrated energy; carry fat-soluble vitamins A, D, E, K; supply essential fatty acids.
- Vitamins and minerals: supply no energy but regulate body processes.
- Fibre and water: fibre prevents constipation; water regulates temperature and transport.
Deficiency signatures you must not mix up
- Protein-energy malnutrition: kwashiorkor shows oedema, pot belly and hair/skin changes; marasmus shows severe wasting without oedema.
- Vitamin A: night blindness, Bitot's spots, xerophthalmia.
- Vitamin D: rickets in children, osteomalacia in adults.
- Vitamin C: scurvy with bleeding gums.
- Iron: iron-deficiency anaemia. Iodine: goitre.
- Thiamine (B1): beriberi. Niacin (B3): pellagra - dermatitis, diarrhoea, dementia.
Worked example
A thali supplies 60 g carbohydrate, 20 g protein and 10 g fat. Energy = (60 × 4) + (20 × 4) + (10 × 9) = 240 + 80 + 90 = 410 kcal. Fat contributes 90 ÷ 410 ≈ 22% of energy, inside the usual guidance of keeping fat below 30%. The reasoning: gram values are fixed constants, so energy is a simple sum, and the percentage tells you whether the meal's fat load is acceptable.
Traps that cost marks
- Writing that vitamins provide energy.
- Using kwashiorkor and marasmus interchangeably.
- Naming the wrong vitamin for rickets (it is D, not C).