What's in a cholesterol test?
| Result | What it is | In general |
|---|---|---|
| LDL cholesterol | Carries cholesterol into artery walls | Lower is better; your target depends on your risk |
| HDL cholesterol | Helps carry cholesterol away | Low levels are linked to higher risk |
| Triglycerides | A type of blood fat, affected by recent meals, alcohol and sugar | High levels often go with insulin resistance |
| Total cholesterol | All cholesterol combined | Less useful on its own |
| Non-HDL cholesterol | Total minus HDL | Captures all the "harmful" particles |
Why there's no single "normal" number
Doctors judge LDL against your overall cardiovascular risk, which takes into account your age, blood pressure, smoking, diabetes, kidney function and family history. Someone who has had a heart attack needs a much lower LDL than a young, otherwise healthy person.
The South African dyslipidaemia guideline (2018), for example, sets non-HDL cholesterol targets of below 2.6 mmol/L for people at very high risk and below 3.3 mmol/L for people at high risk. Your doctor will tell you which category applies to you.
Do I need to fast?
Usually not. South African guidance notes that non-fasting tests give similar results for total, LDL and HDL cholesterol. Triglycerides are affected by food, so your doctor may repeat them fasting if they're high.
When should South Africans get tested?
The 2018 South African guideline recommends testing:
- from age 8, for children with a family history of severe high cholesterol or a relative with familial hypercholesterolaemia;
- from age 20, for adults with risk factors such as high blood pressure, smoking, early heart disease in the family, obesity, autoimmune inflammatory disease or chronic kidney disease;
- from age 40, for everyone else.
Inherited high cholesterol is common in South Africa
Familial hypercholesterolaemia (FH) is an inherited condition causing very high LDL from birth. It affects about 1 in 500 people in most populations, but it is far more common in some South African communities because of a "founder effect":
- about 1 in 75 in the white Afrikaans-speaking community;
- about 1 in 100 in the Lithuanian Jewish and Gujarati Indian communities.
FH greatly increases the risk of early heart disease, but it is very treatable when found. Clues include an LDL above 5 mmol/L in an adult, or a parent or sibling with heart disease before age 55. If one family member has FH, their relatives should be tested too.
What lowers cholesterol?
- Eat more fibre (oats, legumes, vegetables, fruit) and replace saturated fats with unsaturated fats such as olive oil, nuts and fish.
- Stay active.
- Lose weight if you carry excess weight. This particularly helps triglycerides and HDL.
- Limit alcohol and sugar, which raise triglycerides.
- Stop smoking.
Lifestyle changes help, but for people at higher risk, or with FH, medicines are often needed and very effective. South African guidance suggests rechecking after about six months of lifestyle changes alone.
When to see a doctor
Get tested if you:
- are 40 or older and have never been tested;
- have any of the risk factors above;
- have a parent or sibling with high cholesterol or early heart disease;
- belong to one of the communities with higher FH rates and have not been tested.
Frequently asked questions
Is HDL always "good"?
Low HDL is linked to higher risk. Raising HDL with medicines hasn't been shown to reduce heart attacks, so the focus is usually on LDL and overall risk.
Can thin, fit people have high cholesterol?
Yes, especially with FH, which is genetic.
Does eating eggs raise cholesterol?
For most people, dietary cholesterol has a smaller effect than saturated fat, weight and genetics. Your overall eating pattern matters most.
How often should I recheck?
It depends on your results and risk. Your doctor will advise you.
References
- Ampath. AmpathChat 61: SA dyslipidaemia guidelines. 2019. https://ampath.co.za/storage/416/ampathchat-61-sa-dyslipidaemia-guidelines-17102019-final.pdf
- Klug E et al. South African dyslipidaemia guideline consensus statement 2018. SA Heart Journal.
- Mediclinic. Familial hypercholesterolaemia. https://www.mediclinic.co.za/en/infohub-corporate/conditions/familial-hypercholesterolaemia.html
- Alberti KGMM et al. Harmonizing the metabolic syndrome. Circulation. 2009.
This article is for general educational purposes only, like a health newsletter. It is not medical advice, diagnosis or treatment, and reading it does not create a doctor and patient relationship. Please speak to your own doctor about your situation. In an emergency, call 10177 or 112, or go to your nearest emergency unit.