Hypercholesterolemia – an excess of cholesterol – is a metabolic disorder that afflicts up to 30 per cent of adults. It’s one of the main risk factors for cardiovascular disease.
There are two main types. The first, less frequent, is an inherited defect in the liver’s metabolism that can induce hypercholesterolemia in childhood and requires intensive treatment all through life.
The second affects adults, usually because of an unhealthy lifestyle – specifically eating too much food or the wrong kind.
Cholesterol is a lipid, a molecule of fat, that is indispensable to our cells. It’s incorporated into the cellular membranes and is part of various metabolic pathways.
Three-quarters of cholesterol comes from the liver and the rest from food. To reach all cells in the body, the cholesterol in the blood has to be bound to lipoproteins. LDL cholesterol, one of the main protein types, transports lipids from the liver but potentially any excess within the arterial wall as well, which can cause a plaque of cholesterol (also called plaque of atheroma) to form.
Such plaque can progressively narrow the vessel, slowing the blood flow to the organs. The plaque can also rupture and trigger a clotting process that can abruptly interrupt blood flow and thus the crucial oxygen and nutrient supply to the cells.
A heart attack can result if the clot is in a coronary artery, a stroke if in cerebral artery and peripheral artery disease if in a leg.
HDL cholesterol does the opposite of LDL, bringing the lipids back from the arterial wall to the liver to be removed from the blood. HDL helps limit and even reduce plaque, so the more HDL the better. You can see why LDL is often referred to “bad cholesterol” and HDL as “good”.
VLDL meanwhile transports the lipids called triglycerides. An excess of triglycerides also narrows the arteries.
Abnormal cholesterol and excessive blood lipid levels produce no symptoms that might alert you of danger. You need to be screened with a “blood lipid profile”. Total cholesterol is deemed ideal if below 200mg/dL, borderline if between 200 and 239 and too high if it exceeds 240.
Ideally LDL should be below 130mg/dL, but individuals at high risk of cardiovascular disease need to get lower than that – in practice, the lower the better. For HDL, protective levels are above 60mg/dL.
An abnormal lipid profile has to be taken seriously, especially if you have any of the other risk factors for heart disease, such as hypertension, smoking, diabetes or a family history of cardiac problems.
Getting your lifestyle back in healthy shape is essential. It will often bring lipids to acceptable levels. Quit smoking, cut way back on the alcohol, eat more sensibly with the focus on low-cholesterol food, and exercise regularly.
Dr Gerard Lalande is managing director of CEO-Health, which provides medical referrals for expatriates and customised executive medical check-ups in Thailand. He can be contacted at gerard. firstname.lastname@example.org.