“I have high bad cholesterol, but my good cholesterol is good, so I’m not that bad, right?”
"Total cholesterol is the sum of the good and the bad"
“They told me to raise my good cholesterol… but I don’t know how to do that.”
“I thought all cholesterol was bad, what do you mean there’s good cholesterol?”
“The doctor explained to me that good cholesterol protects me, but he still prescribed me a diet…”
“My bad cholesterol is borderline, but with exercise I’m sure I can lower it.”
Surely throughout your life you've heard thousands of phrases like these or very similar ones, talking about, comparing, or evaluating clinical tests of people with positive or negative results regarding two super important parameters: good cholesterol and bad cholesterol.
Today we'll uncover the truth about these values, why they're called that, and the medical and scientific truth behind them. But before going into in-depth explanations, let's discuss the current situation.
What is cholesterol and why is it so important?
Cholesterol is a fatty molecule, a sterol-type lipid. It is essential for life , as it is present in all our cells. It is part of the cell membrane, providing strength but also flexibility to the cell wall, preventing it from breaking and controlling what enters the cell through the membrane.
In addition to its structural function, it is also a key molecule for the production of:
- Vitamin D: As we explained in the article "debunking myths" about vitamin D
- Sex hormones: Progesterone, estrogens and testosterone.
- Cortisol (stress hormone) and Aldosterone (key hormone in the sodium-potassium pump)
- Bile salts necessary for digestion in the intestine.
- Lipid rafts for cell signaling and molecule transport
Although we often associate it with something negative, the truth is that we couldn't live without cholesterol.
There is only one type of cholesterol , and although we get some of it from food, the majority of our cholesterol is produced in our liver, and from there it travels throughout our body.
What is called good cholesterol and what is called bad cholesterol?
To begin with, what is called good and bad cholesterol is not cholesterol itself, since, as we mentioned, there is only one type.
Cholesterol is produced primarily in the liver and travels throughout the body on particles called lipoproteins, which carry it to the cells that need it. When there's an excess, other lipoproteins collect it and carry it back to the liver for elimination or reuse.
Cholesterol cannot move through the body alone, so it associates with these lipoproteins.
- The lipoproteins that transport cholesterol from the liver to the blood are LDL and are popularly known as " bad cholesterol ."
- The lipoproteins that transport excess cholesterol in the blood back to the liver are HDL and are popularly known as " good cholesterol ."
Therefore, what is known as good and bad cholesterol does not refer to cholesterol itself, but to the amount of cholesterol that travels through the blood in LDL lipoproteins and the amount of cholesterol that travels through the blood in HDL lipoproteins.
Why is this nomenclature incorrect?
For several reasons:
Firstly , because the analyses do not measure free cholesterol, but rather the amount of cholesterol associated with the lipoproteins that carry cholesterol to the blood and the lipoproteins that return cholesterol to the liver.
Secondly , because they are neither good nor bad, rather both are good, but they must maintain a proportion of quantities between both for the human body to function properly.
Thirdly , because another key lipoprotein, VLDL, is being left out.
Explanation of HDL, LDL and VLDL
HDL (High-Density Lipoprotein)
- Popularly known as "good cholesterol"
- It collects excess cholesterol from the tissues and carries it to the liver for elimination.
- Helps clean arteries.
- High levels are usually protective for the heart.
LDL (Low-Density Lipoprotein)
- Popularly known as "bad cholesterol"
- Transports cholesterol from the liver to the cells.
- If there is too much, it can accumulate in the arteries and form atheromatous plaques.
- High levels increase cardiovascular risk
VLDL (Very Low-Density Lipoprotein)
- Triglycerides in motion
- Transports triglycerides (another fat) from the liver to the tissues.
- When transformed, it gives rise to LDL.
- It can also contribute to the formation of plaque in the arteries.
What's the truth about cholesterol?
- When the ratio of LDL to HDL is incorrect, there is an excess of LDL in the blood, as there is not enough HDL to collect the excess LDL. This excess cholesterol associated with LDL builds up in the arteries, generating atheromas (fatty deposits) that reduce blood flow through them and can cause them to collapse, leading to serious problems such as heart attacks , strokes , and peripheral vascular disease .
- The incorrect ratio of LDL, HDL, and VLDL in the blood is known as dyslipidemia and is commonly referred to as "having high cholesterol" or "having high bad cholesterol."
- For proper cardiovascular health, it's important to have both the correct LDL/HDL ratio and the sum of the two within the limits. It's no use having the correct total if this is due to having a very low HDL.
- LDL levels rise due to poor nutrition, but they can also rise due to a sedentary lifestyle, smoking, hypothyroidism, or genetic factors.
- High HDL is achieved almost exclusively through physical exercise, although a diet high in healthy fats also helps.
- High VLDL is caused by the same negative factors as LDL, but also by excessive alcohol consumption, type 2 diabetes, or metabolic syndrome.
- VLDL is not measured directly in most tests, but is estimated from triglyceride levels.
What are the correct values for lipoproteins and how is cardiovascular risk calculated?
Values may vary slightly by country or by the patient's medical condition, but in general, the recommended values are as follows:
| Type | Optimal value | Description |
| HDL + LDL + VLDL | < 200 mg/dL | Total blood cholesterol level. |
| LDL |
< 100 mg/dL (normal conditions) <70 mg/dL (if there is cardiovascular risk) |
High values are associated with atheromas and cardiovascular diseases. |
| HDL |
> 40 mg/dL in men > 50 mg/dL in women |
The higher the better, as it protects the arteries and the heart. |
| VLDL | 5-40 mg/dL (approximate) | It is calculated by dividing the triglyceride value by 5. |
| Triglycerides | < 150 mg/dL | High levels increase the risk of heart disease. |
Cardiovascular risk is calculated using risk calculators such as SCORE2 (Europe), Framingham (USA), REGICOR (Spain) or QRISK (UK).
These tools take into account factors such as age, sex, smoking, blood pressure, cholesterol and HDL, diabetes, BMI, and family history.
Most calculators provide a percentage risk of suffering a cardiovascular event (such as a heart attack or stroke) in the next 10 years.
For example:
- Low risk: < 5%
- Moderate risk: 5–10%
- High risk: > 10%
Depending on the results, a decision is made as to whether lifestyle changes, medication, or further testing are necessary.