Explain how a diet high in saturated fat and salt can lead to cardiovascular disease.

Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 1.1 Cardiovascular disease and risk · Explain · 5 marks · View as Markdown

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

Cardiovascular disease is one of the leading causes of death in the UK. Lifestyle factors, including diet, are known to increase a person's risk of developing the condition.

Model answer (5 marks)

A diet high in saturated fat increases the amount of LDL‑cholesterol in the blood. The excess LDL is deposited in the intima of arteries, forming fatty deposits (plaques or atheroma). These plaques narrow the arterial lumen, restricting blood flow to tissues.
A diet high in salt raises blood pressure. The increased pressure stresses the arterial walls, making them more likely to be damaged and to rupture. High blood pressure also favours the formation of plaques and raises the risk of a heart attack or stroke.

Examiner tips

Use the exact terms: LDL‑cholesterol, atheroma, lumen, blood pressure, heart attack, stroke
Show the causal chain: saturated fat → ↑LDL → plaque → narrowed lumen → reduced flow
Include the effect of salt on blood pressure and artery damage

Common mistakes

Confusing HDL with LDL as the harmful cholesterol
Omitting the link between high blood pressure and artery damage
Using vague terms like "fatty stuff" instead of "plaques/atheroma"

Mark scheme (5 marks)

A diet high in saturated fat leads to increased blood cholesterol levels
High cholesterol leads to the formation of fatty deposits (plaques/atheroma) in artery walls
Fatty deposits narrow the lumen of the arteries, restricting blood flow
A diet high in salt increases blood pressure
High blood pressure increases the risk of damage to artery walls / increases the chance of a heart attack or stroke

Key terms in this question

saturated fat · cardiovascular disease