HDL CHOLESTEROL, LDL CHOLESTEROL AND TRIGLYCERIDES

HDL CHOLESTEROL, LDL CHOLESTEROL AND TRIGLYCERIDES

There is good cholesterol and there is bad cholesterol. Find out why it’s good to have high HDL, but LDL should be low.

Cholesterol is a subject that a lot of people have heard of, but few of them are really enlightened on the subject. Who has never heard of the terms: good cholesterol, bad cholesterol, high cholesterol, low cholesterol, HDL, LDL, VLDL and triglycerides?

We are bombarded daily with information of all kinds about cholesterol. Acronyms that do not make sense and values ​​are often thrown on the patients, without it receiving the least guidance to be able to take advantage of so much information available.

The purpose of this text is exactly to complicate the cholesterol issue. Let’s explain in a simple yet complete way the key information you must have to finally understand what cholesterol and atherosclerosis is.

In this text, we will address the following points:

What is cholesterol?

What is atherosclerosis?

What is dyslipidemia?

What types of cholesterol are there?

What is good cholesterol?

What is bad cholesterol?

What are the consequences of high cholesterol?

What are the symptoms of high cholesterol?

Is high HDL cholesterol harmful to your health?

What is the best treatment for high cholesterol?

What is cholesterol?

Much is heard talking about good and bad cholesterol, but little is explained about its real meaning.

Cholesterol is a fatty substance found in every cell in our body. It is essential for the formation of the membranes of our cells, for the synthesis of hormones, such as testosterone, estrogen, cortisol and others, for the production of bile, for the digestion of fatty foods, for the formation of myelin (a sheath covering Nerves), to metabolize some vitamins (A, D, E and K), etc.

The cholesterol in our body has two origins:

A) Endogenous – cholesterol is produced by our own body, mainly by the liver.

B) exogenous – cholesterol can also be is acquired through food.

Types of Cholesterol

As it is a fatty substance, cholesterol does not dissolve in the blood, just as oil drops do not dissolve in water. Therefore, to travel through the bloodstream and reach the peripheral tissues, cholesterol needs a carrier. This function belongs to the lipoproteins that are produced in the liver. The main ones are:

  • VLDL (Very low-density lipoprotein)
  • LDL (Low-density lipoprotein)
  • HDL (High-density lipoprotein)

LDL carries cholesterol and some triglycerides from the blood to the tissues. VLDL carries triglycerides and a little cholesterol. HDL is a different carrier, it makes the reverse path, strips cholesterol from the tissues and returns it to the liver that will excrete it in the intestines.

While LDL and VLDL carry cholesterol to the cells and facilitate the deposition of fat in the vessels, HDL does the reverse, promotes the removal of excess cholesterol, including arterial plaques. Therefore, we call HDL as good cholesterol and VLDL and LDL as bad cholesterol.

The production of lipoproteins is regulated by cholesterol levels. Cholesterol derived from saturated fats and trans fats favor LDL production, while consumption of unsaturated fats found in olive oil, fish and almonds, for example, promotes the production of HDL.

Therefore, by dosing the values ​​of the LDL, VLDL and HDL carrier lipoproteins, we have an indirect evaluation of the quantity and quality of cholesterol circulating in our blood. Therefore, the lipidogram, the test used to measure lipoproteins, is used to evaluate blood cholesterol levels.

What is IDL Cholesterol?

IDL (Intermediatelow-density lipoprotein) is a type of LDL-like cholesterol. As it has similar effects, it is not normally dosed individually, but together with LDL. So when we get the value of LDL, we are usually talking about the value of LDL + IDL.

What is atherosclerosis?

Elevated concentrations of VLDL and LDL are associated with deposition of fat in the wall of blood vessels, leading to the formation of cholesterol plaques. When our body has more cholesterol than it needs, the LDL molecules are circulating in the blood in search of some tissue that is in need of cholesterol for its functioning. If this cholesterol is not delivered to any tissue, the LDL molecule ends up depositing inside the wall of the blood vessels, accumulating fat in them. This process is called atherosclerosis

Atherosclerosis See the illustration on the side as these fat plates occupy space and decrease the diameter of the light of the vessels (we call light the hollow part of the vessels through which the blood passes). Atherosclerosis also causes direct damage to the wall, decreasing the elasticity of the arteries, making them harder.

Fat deposition and vessel wall damage favor obstruction of blood flow and reduction of oxygen and nutrient supply to tissues. When the vessels affected by the cholesterol plaques are the coronary arteries (arteries of the heart), the end result may be cardiac infarction When cerebral vessels are involved, the patient may develop a stroke .

Dyslipidemia

The increase in cholesterol levels is called dyslipidemia. For a long time physicians have assessed the degree of dyslipidemia through total cholesterol values, which is nothing more than the sum of blood levels of HDL + LDL + VLDL. However, as we have just explained, there is bad cholesterol and good cholesterol, which makes it difficult to jointly evaluate them. Currently, total cholesterol is less valued than individual levels of HDL and LDL.

See these examples:

Patient 1 – LDL 150, HDL 20 and VLDL 20 = total cholesterol of 190

Patient 2 – LDL 100, HDL 65 and VLDL 25 = total cholesterol of 190

From what has been explained so far, there is no doubt that patient 1 presents more risks of atherosclerosis than patient 2, despite having the same total cholesterol level. The above example explains why total cholesterol is not the best parameter for assessing dyslipidemia.

HDL Cholesterol and LDL Cholesterol

As dyslipidemia is one of the major risk factors for cardiovascular disease, medicine has been trying to establish through studies what are the optimal levels of HDL and LDL cholesterol. We currently classify cholesterol as follows:

LDL

Less than 100 mg / dL – Great

Between 101 and 130 mg / dL – Normal

Between 131 and 160 mg / dL – Normal / high

Between 161 and 190 mg / dL – High

Greater than 190 mg / dL – Very high

HDL

Less than 40 mg / dL – Low (bad)

Between 41 and 60 mg / dL – Normal

Greater than 60 mg / dL – High (optimum)

What to do when your cholesterol is high?

A diet rich in unsaturated fats and low in saturated fats is indicated for all people, regardless of the value of their cholesterol. But if you have dyslipidemia, following this diet is even more important.

However, not alone solves the problem of high cholesterol, because the increase in LDL cholesterol is related to genetic and food factors. 75% of our cholesterol is of endogenous origin (produced by the liver) and only 25% comes from food. So, if LDL values are too high, only the diet will not be enough to normalize bad cholesterol values.

Physical exercise helps elevate HDL and lower LDL, and is another option for controlling dyslipidemia. However, just as in the diet, the reduction is also not great. Diet and exercise are sufficient for those patients with LDL up to 160 mg / dl. This is the group that can achieve good results without having to resort to medicines.

The decision as to when to start the medication depends not only on the LDL and HDL values, but also on the presence of other risk factors for cardiovascular disease, namely:

  • Smoking
  • Hypertension
  • Diabetes
  • Chronic renal failure
  • Obesity and Metabolic Syndrome
  • Age greater than 45 years.

The more risk factors you have, the lower your cholesterol should be. Roughly speaking, we can summarize the targets as follows:

Patient with only one risk factor – LDL cholesterol should be less than 160 mg / dL.

Patient with two or more risk factors – LDL cholesterol should be less than 130 mg / dL.

Patients with a high cardiovascular risk, especially if they have had a heart attack or stroke – LDL cholesterol should be less than 100 mg / dL.

Since 2013, however, there are new consensus on the treatment of high cholesterol, which no longer give as much relevance to LDL values. Instead of focusing on a target LDL value, treatment is indicated in patients at high cardiovascular risk, even if LDL levels are not very high. We explain in detail the new way of treating dyslipidemia in the following article: Do I Need to Take Medicines to Lower Cholesterol?

Is high HDL harmful?

No, on the contrary. Some people, usually women, have very high HDL, sometimes above 100 mg / dL. This does not indicate any disease. In fact, they are fortunate people because they have a low risk of heart disease, especially if LDL is low.

So having high HDL is good as this is a form of cholesterol that protects us against atherosclerosis.

What is non-HDL cholesterol?

Non-HDL cholesterol is the sum of all types of cholesterol considered bad: IDL + LDL + VLDL. Non-HDL cholesterol is thought to be a more sensitive marker of risk of atherosclerosis than LDL alone.

Values ​​of non-HDL cholesterol:

Less than 130 mg / dL – Great

Between 131 and 160 mg / dL – Normal

Between 161 and 190 mg / dL – Normal / High

Between 191 and 220 mg / dL – High

Greater than 220 mg / dL – Very high

What are the symptoms of high cholesterol?

None! High cholesterol does not cause symptoms.

Attention: high cholesterol does not give tiredness, headache, shortness of breath, prostration or any other symptom. Dyslipidemia is a silent disease. The only way to know cholesterol levels is through lipidogram.

Triglycerides

Hypertriglyceridemia, a name given to increased triglycerides in the blood, is also a risk factor for atherosclerosis, especially if associated with low levels of HDL.

Triglycerides are closely linked to VLDL and their value is usually 5x higher. For example, an individual with VLDL of 30 mg / dL will have triglyceride levels around 150 mg / dL.

Normal triglyceride values ​​are:

Up to 150 mg / dL = normal

Between 150 and 199 mg / dL = borderline

Between 200 and 500 mg / dL = high

Greater than 500 mg / dL = very high

Elevated cholesterol and, especially, triglycerides, are associated with a higher incidence of fatty accumulation in the liver, called hepatic steatosis.

Medicines used to treat high cholesterol (dyslipidemia)

Any patient with high cholesterol and / or triglyceride should undergo diet, exercise regularly, and if you are overweight, lose weight.

The drugs of choice for lowering LDL and increasing HDL are statins, also called inhibitors of the enzyme HMG-coA reductase (the liver enzyme responsible for cholesterol production). Statins also act to lower triglycerides.

The most prescribed statins are:

  • Simvastatin.
  • Atorvastatin.
  • Fluvastatin.
  • Pravastatin.
  • Rosuvastatin.
  • Lovastatin.

Rosuvastatin and atorvastatin are the strongest and can achieve lower cholesterol reductions. However, these two are expensive and often the patient is able to control their cholesterol with the cheapest statins, and it is not necessary to use the most potent drugs.

The main side effects of these medications are muscle pain and cramps. In some cases muscle damage can be serious and indicate discontinuation of treatment. Medicated hepatitis may also occur

Although statins act on triglyceride levels, fibrates are a class with more intense action for this purpose. Fibrates reduce triglycerides, but practically do not interfere with LDL cholesterol.

The most commonly used fibrates are:

  • Fenofibrate
  • Benzafibrato
  • Genfibrozil
  • Clofibrate
  • Ciprofibrate

The association between fibrates and statins should be made with caution, since there is an increased risk of muscle injury with the concomitant use of these drugs.

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