Cardiovascular disease and diet (SACE Stage 2 Nutrition)
“Explain the development of cardiovascular disease and the dietary factors that increase or reduce its risk”
Cardiovascular disease (CVD) affects the heart and blood vessels and is the result of atherosclerosis, the build-up of fatty plaques that narrow and harden arteries. Over time this can block blood flow and cause heart attack or stroke. Diets high in saturated and trans fats, salt and excess energy raise the risk by increasing blood cholesterol, blood pressure and body fat, while unsaturated fats, fibre, fish, fruit and vegetables help lower it. You should be able to explain how CVD develops and the dietary factors that raise or reduce risk.
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What this dot point is asking
You need to explain how cardiovascular disease develops, then explain which dietary factors increase the risk and which reduce it.
How cardiovascular disease develops
Cardiovascular disease (CVD) is a group of conditions affecting the heart and blood vessels, including coronary heart disease and stroke. Its main underlying process is atherosclerosis.
In atherosclerosis, fatty deposits called plaques build up on the inner walls of arteries. The arteries become narrowed and stiffened, so blood flow is reduced and blood pressure rises. If a plaque ruptures, a blood clot can form and block the artery. A blockage in an artery supplying the heart causes a heart attack; a blockage or bleed in the brain causes a stroke.
Cholesterol carried in the blood plays a key role. Low-density lipoprotein (LDL) cholesterol tends to deposit in artery walls, while high-density lipoprotein (HDL) helps remove it, which is why the balance of blood lipids matters.
Dietary factors that increase risk
- Saturated and trans fats
- Diets high in saturated fat (fatty meats, butter, many processed foods) and trans fats tend to raise LDL cholesterol, promoting plaque build-up. Trans fats are particularly harmful.
- Salt (sodium)
- A high salt intake raises blood pressure, which damages artery walls and strains the heart, increasing CVD risk.
- Excess energy
- Diets high in energy from fat and sugar promote overweight and obesity, which are linked to high blood pressure, unhealthy blood lipids and type 2 diabetes, all of which raise CVD risk.
Dietary factors that reduce risk
- Unsaturated fats
- Replacing some saturated fat with unsaturated fats from oils, nuts and oily fish helps improve blood lipids. Oily fish supplies omega-3 fatty acids linked to heart health.
- Dietary fibre
- Soluble fibre from oats, legumes, fruit and vegetables can help lower LDL cholesterol.
- Fruit, vegetables and wholegrains
- These supply fibre, potassium and protective compounds, and support a healthy weight and blood pressure.
- Less salt and moderate energy intake
- Reducing salt helps control blood pressure, and matching energy intake to needs helps maintain a healthy weight.
These align with the Australian Dietary Guidelines, which is why the guidelines emphasise vegetables, wholegrains, lean proteins and limiting saturated fat and salt.
Cardiovascular disease mostly arises from atherosclerosis: fatty plaques narrow and harden arteries, raising blood pressure and risking a clot that blocks blood flow to the heart (heart attack) or brain (stroke). Diet influences this through blood cholesterol, blood pressure and body weight.
Why this matters
CVD is a leading cause of death, and much of its risk is influenced by modifiable diet and lifestyle factors. This makes it a central example of the diet to disease link and a common examination case study, where you may be asked to evaluate a diet and recommend changes.
Step 1: Identify the risky features of the diet
A case describes a man who eats fatty meat and butter daily, frequent salty takeaway, few vegetables and little fish. Flag each feature: high saturated fat, high salt, low fibre, low omega-3.
Step 2: Link each feature to a mechanism
High saturated fat raises LDL cholesterol and plaque build-up; high salt raises blood pressure; low fibre means LDL is not lowered; low omega-3 misses the protective effect on blood lipids and rhythm.
Step 3: Recommend a specific swap for each
Replace butter and fatty meat with olive oil, nuts and lean protein (lower saturated fat); cut salty takeaway and check labels (lower blood pressure); add oats, legumes, fruit and vegetables (more soluble fibre); include oily fish twice a week (omega-3).
Step 4: Justify against the process
Tie the changes back to atherosclerosis: lower LDL, lower blood pressure and a healthier weight all slow plaque build-up and reduce CVD risk. A high-mark answer pairs each change with its mechanism, not just a list of healthy foods.
- Saying all cholesterol is bad
- The body needs cholesterol; the issue is high LDL and low HDL in the blood, influenced partly by the type of fat eaten.
- Blaming only fat
- Salt (through blood pressure) and excess energy (through overweight) are major dietary contributors too, not just fat.
- Treating all fats as equal
- Saturated and trans fats raise risk, while unsaturated fats, especially omega-3 from fish, can lower it.
- Forgetting the process
- Marks come from explaining atherosclerosis and how diet feeds into cholesterol, blood pressure and weight, not just listing risky foods.
In short, cardiovascular disease develops through atherosclerosis driven by blood cholesterol, blood pressure and body weight, and diets low in saturated fat and salt but rich in unsaturated fats, fibre, fish and vegetables help reduce the risk.
Exam-style questions
Questions in the style of SACE Board exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
2019 SACE Stage 2-style3 marksA family frequently consumes packaged, dehydrated instant noodles. Explain the link between pre-prepared meals and hypertension, with reference to a specific Australian dietary guideline.Show worked answer →
Three marks: explain the salt/sodium link to hypertension (about 2 marks) and quote a relevant guideline (1 mark).
Pre-prepared meals such as instant noodles are typically very high in sodium (salt), which is added for flavour and preservation. A diet high in sodium causes the body to retain more water, which increases blood volume and therefore raises blood pressure. Sustained high blood pressure is hypertension, a major risk factor for cardiovascular disease (2 marks).
Australian Dietary Guideline 3 advises Australians to limit intake of foods and drinks containing added salt (and saturated fat and added sugars). Choosing pre-prepared meals frequently works against this guideline because of their high salt content (1 mark).
2018 SACE Stage 2-style1 markState two functions of omega-3 fatty acids in the human body.Show worked answer →
One mark for a correct function (the original question allocates one mark per function).
Omega-3 fatty acids help maintain heart and cardiovascular health by lowering blood triglyceride levels and reducing the risk of abnormal heart rhythms and blood clots.
Other accepted functions include supporting brain development and function, and reducing inflammation in the body. Omega-3 is a polyunsaturated fat that helps replace saturated fat in the diet, lowering cardiovascular disease risk.
Practise this
Sources & how we know this
- Stage 2 Nutrition subject outline (2025 onwards) — SACE Board
- Stage 2 Nutrition: external assessment — SACE Board