A school nurse is reviewing the health records of students at a secondary school. She notices that several students have diets that are unbalanced in different ways. Describe how deficiencies in different nutrients can lead to specific health problems.

OCR A-Level Biology B — Advancing Biology (H422) — 2.3 Diet, nutrition and health · Describe · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

A balanced diet contains carbohydrates, proteins, fats, vitamins, minerals, fibre and water. When one or more of these nutrients is missing or present in insufficient amounts, deficiency diseases or health problems can develop.

Model answer (5 marks)

Lack of vitamin C – scurvy, characterised by bleeding gums, bruising and poor wound healing.
Lack of vitamin D – rickets, leading to weak or soft bones and skeletal deformities.
Lack of iron – anaemia, reducing the blood’s capacity to carry oxygen and causing fatigue.
Lack of protein – poor growth, muscle wasting and kwashiorkor, with oedema and skin changes.
Lack of fibre – constipation, digestive problems and an increased risk of bowel disease.

Examiner tips

  • Use the exact disease names (scurvy, rickets, anaemia, kwashiorkor) and link each nutrient to its specific symptom. Show the cause–effect chain: nutrient → deficiency → disease. Keep each point brief and to the point to fit the 5‑mark limit.

Common mistakes

  • Mixing up vitamin C with vitamin A; confusing rickets with osteomalacia. Failing to mention the specific symptom (e.g. bruising for scurvy) or giving a generic ‘weakness’. Using vague terms like ‘poor health’ instead of the disease name.

Mark scheme (5 marks)

  1. Lack of vitamin C causes scurvy
  2. Lack of vitamin D causes rickets (weak/soft bones)
  3. Lack of iron causes anaemia (or reduced ability to carry oxygen)
  4. Lack of protein causes poor growth / muscle wasting / kwashiorkor
  5. Lack of fibre causes constipation / problems with the digestive system / increased risk of bowel disease

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