LDL (Bad) Cholesterol
LDL cholesterol is considered the “bad” cholesterol because it contributes to plaque, a thick, hard deposit that can clog arteries and make them less flexible. This condition is known as atherosclerosis. If a clot forms and blocks a narrowed artery, heart attack or stroke can result. Another condition called peripheral artery disease can develop when plaque buildup narrows an artery supplying blood to the legs.
There is no such thing as good cholesterol and bad cholesterol. Cholesterol is cholesterol. The chemical formula for cholesterol is C27H46O. There is no good version or bad version of this formula.HDL is not even cholesterol, let alone good. LDL is not even cholesterol, let alone bad. HDL stands for High Density Lipoprotein. LDL stands for Low Density Lipoprotein. (There are three other lipoproteins, by the way, chylomicrons, VLDL and IDL).
Fat and cholesterol are not water soluble so they need to be carried around the body in something to do their vital work. The carriers of such substances are called lipoproteins. We can think of lipoproteins as tiny ‘taxi cabs’ travelling round the blood stream acting as transporters. So, lipoproteins are carriers of cholesterol – oh – and triglyceride and phospholipids and protein. All lipoproteins carry all of these substances – just in different proportions. LDL would more accurately be called the carrier of fresh cholesterol and HDL would more accurately be called the carrier of recycled cholesterol.
iv) The standard blood cholesterol test does not measure LDL – it estimates it. The fasting blood cholesterol test can only measure total cholesterol and HDL. There are two other unknowns in a four variable equation – LDL and VLDL. The estimation is refined further using the Friedewald equation (named after William Friedewald, who developed it).
If your cholesterol is anywhere on those normal charts (2-10 mmol/l = 77-387 mg/dl) – you may like to stop worrying.
You should also be aware that the blood cholesterol test doesn’t actually measure LDL (the thing they call ‘bad cholesterol’ – which is not even cholesterol – it’s a Low Density Lipoprotein) – they guess it. See point iv here. You should also be aware that even the total cholesterol, which they do try to measure, is known to be out by as much as 19%.
If you actually have high cholesterol (e.g. 10 mmol/l = 387 mg/dl or above) OR your cholesterol is high for you (i.e. relative to what you know yours normally is – your normal – not the made up normal), remember that your body makes cholesterol for good reason and consider the following: are you injured? stressed? pregnant? recovering from an operation? illness? Any of these will encourage your body to make more cholesterol.
Have you had a cholesterol test taken at the end of winter? in the heart of winter? Vitamin D is made by sunlight synthesizing cholesterol on the skin when you expose your skin to sunlight. Your cholesterol may simply be ‘high’ right now because you haven’t turned it into vitamin D (it’s the low vitamin D that will harm you – not the ‘high’ cholesterol – the high cholesterol can be a sign that you’re lacking vitamin D). Have another test at the end of the summer and make sure you give your body the chance to make some vitamin D with healthy sun exposure (not too much, not burning).
It is considered important to keep cholesterol levels, especially LDL-C within certain limits. If you have other risk factors for heart disease, such as high blood pressure, diabetes, or if you smoke, keeping LDL-C low becomes even more important.
Here you can see how LDL-C levels are looked at in terms of risk:
- above 190 mg/dL (4.9 mmol/L) is considered very high
- 160 – 189 mg/dL (4.1 – 4.9 mmol/L) is considered high
- 130 – 159 mg/dL (3.4 – 4.1 mmol/L) is considered borderline high
- 100 – 129 mg/dL (2.6 – 3.3 mmol/L) is considered near ideal
- below 100 mg/dL (below 2.6 mmol/L) is considered ideal for people at risk of heart disease
- below 70 mg/dL (below 1.8 mmol/L) is considered ideal for people at very high risk of heart disease
How Can You Influence Your LDL Cholesterol?
If your LDL-C is high, your doctor will probably suggest lifestyle changes. Quitting smoking will be helpful and so may eating whole grain, oatmeal, olive oil, beans, fruit, and vegetables. Most doctors will recommend eating less fat from meat and dairy products.
Regular exercise is desirable. Losing weight may be helpful.
Some studies show that low-carbohydrate diets may positively affect LDL particle size and number.
If lifestyle changes don’t help, your doctor may suggest medications that lower cholesterol. So-called statins are the most commonly used drugs for lowering cholesterol.
Studies have shown that statins improve prognosis among patients with coronary artery disease. Their role for treatment of raised LDL-C in healthy people (primary prevention) is less clear. The decision to give statins in primary prevention is usually based on other risk factors as well as the LDL-C value itself.
A new type of blood test may help physicians identify which patients with and without evidence of coronary blockages are at risk for heart attacks and strokes. Even individuals with normal levels of low-density lipoprotein (LDL), known as the so-called "bad" cholesterol, but still at risk, seem to be identified, according to Mayo Clinic research being presented at the American College of Cardiology's 66th Annual Scientific Session.
The test, released commercially by Mayo Medical Laboratories in August 2016, measures blood concentrations of plasma ceramides, a class of lipids that are highly linked to cardiovascular disease processes. The study found that individuals with the highest levels of blood ceramides were found to have a 3- to 4-times greater risk of having a cardiovascular event compared with those with the lowest ceramide score, regardless of their LDL cholesterol level or the presence of a blockage in the heart's arteries.
"Our research suggests that evaluating ceramide levels in patients who are not at immediate risk for coronary artery disease events may help cardiologists decide who could benefit from proactive and preventive treatment, such as statins, or lifestyle changes to prevent a serious cardiac event down the road," says Jeff Meeusen, Ph.D., a clinical chemist, co-director of Cardiovascular Laboratory Medicine at Mayo Clinic and the study's lead author.
According to Dr. Meeusen, ceramides are different than cholesterol, which gathers and causes a clog in the arteries. Ceramides are more active, attracting inflammatory cells and promoting clotting.
In the study, 499 Mayo Clinic patients who were referred for coronary angiography to check for possible artery blockages were included and followed prospectively for approximately eight years. Patients were similar in age and with regard to blood pressure, smoking status and high-density lipoprotein (HDL), the "good" cholesterol; excluded were those who had diabetes or a previous heart attack, stroke or procedure to open narrowed coronary arteries. Researchers measured four different types of ceramides in the blood at baseline and combined the values into a 12-point scale. Patients were grouped into four risk categories according to their ceramide levels: low (0-2), intermediate (3-6), moderate (7-9) and high (10-12).
Over the eight years, researchers recorded occurrences of heart attack, stroke, revascularization and death. Overall, 5.1 percent of patients had a major cardiovascular event each year. But the risk of having an event became higher as ceramide level increased; for each 1-point increase in the ceramide risk score, the risk rose by 9 percent. The rate of events was double among people with the highest ceramide score compared with those with the lowest (8.1 vs. 4.1 percent, respectively).
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