Hypercholesterolaemia: a lipid metabolism disorder
Martina Stuppy Pure hypercholesterolemia means that the LDL cholesterol levels in the blood are too high. Find out everything you need to know here!
In pure hypercholesterolemia, the harmful LDL cholesterol in the blood is elevated, while the useful HDL cholesterol is at too low a level. The disease is quite widespread and often causes no symptoms for a long time, which is why it is only discovered late. Read more here about why excess cholesterol can be so dangerous to your health, where the lipid metabolism disorder comes from and what you can do about it.
This happens with pure hypercholesterolemia
Pure hypercholesterolemia is a lipid metabolism disorder, also known in medicine as dyslipidemia.
The disease is characterized by elevated LDL cholesterol levels, which is also reflected in the name: “hyper” comes from the Greek language and means “too much”, “excessive”. The term “emia” also comes from the Greek and means “blood”. In other words, there is too much cholesterol in the bloodstream.
A short-term increase in LDL cholesterol levels is generally harmless, for example after a high-fat meal. However, in hypercholesterolemia, the level is increased over a longer period of time and this can lead to blood vessel constriction and other life-threatening secondary diseases.
As a rule, the total cholesterol level in the blood of an adult should be below 200 mg/dl (milligrams per deciliter) (5.2 mmol/l).
Total cholesterol is usually made up of 70% LDL cholesterol. The ratio between “good cholesterol” (HDL) and “bad cholesterol” (LDL), the so-called LDL/HDL ratio, is also known in medicine as the “arteriosclerosis risk index”. The more “bad LDL cholesterol” and the less “good HDL cholesterol” a person has, the higher the arteriosclerosis risk index and vice versa.
According to the current guideline for lipid metabolism disorders (dyslipidemias) of the European Society of Cardiology (ESC), an LDL cholesterol level above 116 mg/dl carries an increased risk of cardiovascular disease.
Basically, the LDL cholesterol level should be kept as low as possible. However, the guidelines defined by doctors always refer to the personal risk of developing cardiovascular disease. If a person's LDL cholesterol level is below 116 mg/dl, there is a low risk of suffering from cardiovascular disease within the next ten years. People with familial hypercholesterolemia, for example, have an increased risk of disease. Their LDL cholesterol level should be below 70 mg/dl.
Hypercholesterolemia affects both men and women equally. However, the frequency of this lipid metabolism disorder is age-dependent: it increases with advancing age.
The disease is quite widespread in western industrialized countries: approximately every second person over the age of 40 has elevated cholesterol levels.
In the ICD-10, the international classification of diseases, pure hypercholesterolemia can be found in the chapter “Disorders of lipoprotein metabolism and other lipidemias” under the numbers E78.0-E78.9.
What exactly is cholesterol?
Cholesterol is vital for the human body. Specifically, cholesterol is one of the so-called dietary fats (lipids). It is an important component of the cell membrane and is involved in various metabolic processes in the body. The body also uses cholesterol to produce bile acid, hormones such as testosterone and estrogen, and vitamin D. The body can produce most of the cholesterol it needs itself - around 90%. The remaining 10% must be taken in through daily food. If too much cholesterol is taken in through food, the body tries to compensate for this excess by reducing its own production. This prevents excessively high cholesterol levels in the blood (hypercholesterolemia).
Cholesterol needs proteins in the body as a means of transport in order to move through the blood. The combination of cholesterol, protein and other fats is called lipoprotein. The two best-known lipoproteins are HDL and LDL.
LDL (low density lipoprotein) transports cholesterol from the liver to where it is needed in the body. It has a very important job, but is still colloquially referred to as "bad cholesterol". If there is too much LDL in the blood, the body's cells can no longer absorb it. Cholesterol deposits on the blood vessel walls and, as a result, the vessels narrow: this leads to arteriosclerosis. In the worst case, the deposits in the vessels can break open. This can cause blood clots. If such a blood clot blocks an important cardiovascular vessel or a blood vessel in the brain, a heart attack or stroke occurs.
HDL (high density lipoprotein) is the counterpart to LDL. It returns unneeded cholesterol to the liver, where it can be broken down. This cholesterol has a protective effect and is therefore also referred to as "good cholesterol". However, it is also important here that the HDL value is within a normal range, namely around 40 mg/dl.
There is also VLDL (Very Low Density Lipoprotein): It has a very low density and is a precursor to LDL. These lipoproteins transport many neutral fats (triglycerides) and also cholesterol from the liver to the cells in the body.
Only 30% of cholesterol is free in the body. The remaining 70% is associated with fatty acids (cholesterol esters).
Doctors speak of healthy cholesterol levels when HDL levels are too low and LDL cholesterol levels are high. With unhealthy cholesterol levels, it is exactly the opposite.
Your own lifestyle plays a key role when it comes to healthy cholesterol levels and avoiding dangerous secondary diseases. For example, a low-cholesterol diet with only a few animal fats can make a decisive contribution to healthy levels. But quitting smoking, getting enough physical exercise and maintaining a healthy body weight also have a positive effect.
Symptoms
Pure hypercholesterolemia does not cause any noticeable symptoms. In some cases, skin changes can occur: yellowish, sometimes pimple-like fatty deposits (xanthomas) can form on the legs, arms, buttocks or even on the eyelids. Long-term elevated cholesterol levels can lead to vascular deposits and vascular constriction. As a result, symptoms such as a feeling of tightness in the chest, dizziness, shortness of breath or painful legs can occur.
However, increased LDL cholesterol concentrations in the blood can be seen as a sign of other diseases, because high cholesterol levels can be dangerous for your health:
Arteriosclerosis (hardening of the arteries)
LDL cholesterol ensures internal cholesterol distribution in the body. While HDL lipoproteins are reduced in hypercholesterolemia, LDL in the blood is increased, so that the return transport to the liver is impaired. The excess cholesterol is deposited in the blood vessel walls and this sets the arteriosclerosis process in motion. Along with the cholesterol, fats, blood components, fibrous tissue, carbohydrates and calcium also begin to be deposited in the vessel walls. The risk of cardiovascular disease increases!
Coronary heart disease (CHD) and heart attack
The arteriosclerosis also leads to an increasing narrowing of the blood vessels. If this narrowing affects the coronary arteries, doctors speak of coronary heart disease (CHD). Hypercholesterolemia can also promote a heart attack. In some cases, the coronary arteries can be almost completely blocked, meaning that the heart muscle can no longer be supplied with sufficient oxygen. Those affected feel a strong feeling of pressure and chest pain. Sweating, shortness of breath, rapid heartbeat and dizziness can also be signs of a heart attack.
Peripheral occlusive disease (PAD) and stroke
If the leg arteries are damaged by hypercholesterolemia, a condition known as peripheral occlusive disease (PAD) can occur. Those affected suffer from painful circulatory disorders, particularly during physical exertion such as walking.
However, hypercholesterolemia can also lead to a narrowing of the brain or neck arteries, resulting in a lack of oxygen in the brain. This can lead to short-term neurological deficits (transient ischemic attack TIA), such as hemiplegia, but also to a stroke.
Xanthomas – fatty deposits in the tissue
This involves fatty deposits in the tissue, mainly in the skin. Too much cholesterol and too many fats in the blood lead to fat and cholesterol deposits on the trunk or hands. Yellowish-orange skin thickenings, so-called xanthomas, develop.
Larger yellowish-brownish thickenings on the skin of the knees or elbows are called tuberous xanthomas.
Yellowish nodules also typically appear on the buttocks and on the extensor sides of the legs and arms. These skin conditions are known in medicine as eruptive xanthomas.
Hypercholesterolemia in the human eye
Excess cholesterol can also be deposited in the cornea of the eye. This can result in a visible, grey-white ring of opacity at the edge of the cornea. Doctors refer to this as an arcus lipoides corneae. Such a lipid ring is mainly seen in older people and is considered harmless. If it occurs in people under the age of 45, this is a clear indication of hypercholesterolemia.
Course
The progression of hypercholesterolemia depends on the type of lipid metabolism disorder.
If cholesterol levels are elevated due to poor eating habits, then changing your individual eating habits can help normalize your cholesterol levels.
How secondary hypercholesterolemia progresses depends largely on whether the cause of the lipid metabolism disorder can be successfully treated or eliminated. If, for example, an illness is the reason for the increased cholesterol levels, this should be treated appropriately. If medications lead to hypercholesterolemia, they must be replaced or discontinued.
Purely hereditary forms of lipid metabolism disorders, such as familial hypercholesterolemia, progress in very different ways for each individual. Doctors consider hereditary hypercholesterolemia to be more dangerous because dangerous secondary diseases can occur earlier in these forms than in other forms. This is especially true for people who have inherited the causal genetic trait from both parents. In such a case, it is particularly important to treat the lipid metabolism disorder early and to reduce the elevated cholesterol levels. This also reduces the risk of dangerous secondary diseases.
In general, the course of hypercholesterolemia can be influenced positively. A healthy diet, sufficient exercise in everyday life and the elimination of other risk factors can lower cholesterol levels to a healthy normal level.
Causes and risk factors
In most cases, hypercholesterolemia occurs due to the interaction of various factors. Depending on the underlying causes, doctors differentiate between four different forms:
Reactive-physiological hypercholesterolemia
This is caused by poor lifestyle and eating habits. Typical causes of increased cholesterol levels in the blood are a diet that is too high in cholesterol and an increased intake of trans fats and saturated fatty acids. Overall, this leads to an overload of the metabolism. An acute lack of exercise has additional negative effects.
However, not everyone who lives an unhealthy lifestyle and has high cholesterol levels is affected by reactive-physiological hypercholesterolemia. An unhealthy and unbalanced lifestyle can also lead to mixed forms.
Primary hypercholesterolemia
Elevated LDL cholesterol levels can also have a purely genetic cause. In such a case, doctors speak of primary hypercholesterolemia.
The altered genes lead to greatly increased cholesterol levels. It makes no difference whether the affected patients eat a healthy diet, have previous illnesses or are sufficiently active.
Primary hypercholesterolemia includes, for example, familial hypercholesterolemia. This form of the disease is monogenic, which means that the genetic changes only affect a certain part of the gene (hereditary trait).
In the familial form of hypercholesterolemia, the LDL receptor gene is altered. This only has an effect on cholesterol levels - it is therefore pure hypercholesterolemia.
In familial hypercholesterolemia, high cholesterol levels occur as follows:
- LDL degradation usually takes place in the cells of the liver.
- However, in order for the LDL lipoproteins to enter the liver cells, the LDL must dock at a special docking site – so-called receptors.
- However, due to genetic changes, the liver cell receptors for LDL cholesterol are only partially functional or there are no longer any functioning docking sites.
- As a result, the breakdown of “bad” LDL cholesterol in the liver is impaired and excessive amounts of cholesterol accumulate in the blood.
- The risk of cardiovascular disease increases.
- If only the mother or father inherits the genetic change, the child will suffer from what is known as heterozygous familial hypercholesterolemia. Cholesterol levels are usually between 300 and 500 mg/dl. Approximately one in 500 people are affected by this form of hypercholesterolemia.
- However, if both parents pass on the genetic trait, the child develops homozygous familial hypercholesterolemia. In this case, the cholesterol level in the blood is extremely high, at around 500 – 1200 mg/dl (12.9-30.9 mmol/l).
This form of hypercholesterolemia is very rare and affects only 1 in 1,000,000 people.
Primary hypercholesterolemia can also occur as part of a so-called combined lipid metabolism disorder: In this case, due to the hereditary predisposition, not only the cholesterol level is significantly increased, but also the blood lipid levels. An example of such a combined lipid metabolism disorder is “familial combined hyperlipidemia”.
Secondary hypercholesterolemia
Secondary hypercholesterolemia occurs when other risk factors, behaviors or underlying diseases are the cause of the high cholesterol level.
These possible underlying diseases include:
- Acute intermittent porphyria
This causes neurological symptoms and colicky abdominal pain. Porphyria is a group of rare metabolic diseases that result in a deficiency of enzymes involved in the formation of the red blood pigment heme. Heme is an important component of various important proteins in the body.
- Anorexia
- Diabetes mellitus (diabetes)
- Cholestasis (bile stasis): This is when bile backs up within the bile ducts. The bile cannot flow into the intestine.
- Liver carcinoma (liver cancer)
- Underactive thyroid (hypothyroidism).
Certain medications can also cause secondary hypercholesterolemia. These include androgens, gestagens, thiazides, amiodarone, glucocorticoids, chlorpromazine or beta-blockers.
Behaviors such as an unhealthy diet in everyday life or a lack of exercise can also be responsible for this form of hypercholesterolemia. In addition, this form can also arise as a result of menopause or during pregnancy.
Mixed forms of hypercholesterolemia
In most cases, there are several causes behind elevated cholesterol levels. Such mixed forms can therefore have reactive-physiological, primary or secondary causes at the same time.
The most significant mixed form is the so-called polygenic hypercholesterolemia. Several small changes in different genes are responsible for the high cholesterol levels (which is why they are also called "polygenic"). In addition, other risk factors can often cause such polygenic hypercholesterolemia even without a genetic influence.
The genetic changes are very typical for the polygenic form of hypercholesterolemia, but they are generally not sufficient to cause greatly increased levels. For this reason, in most cases, another trigger is needed for this mixed form to occur. Only then can the LDL cholesterol level in the blood be significantly increased.
Possible triggers for polygenic hypercholesterolemia include, for example, excessive body weight, diabetes mellitus, a very high-calorie and high-fat diet, thyroid dysfunction or certain medications.
therapy
The main goal of hypercholesterolemia is to reduce the high LDL cholesterol level in the blood. This is of key importance in order to minimize the long-term risk of secondary diseases such as arteriosclerosis.
The aim is usually to achieve a cholesterol target value of less than 160 mg/dl. If a patient has two or more risk factors for cardiovascular disease, the cholesterol level should even be less than 130 mg/dl. If a vascular disease such as a heart attack, coronary heart disease (CHD) or peripheral arterial disease (PAD) has already occurred, or if the patient suffers from diabetes, the aim is to achieve a cholesterol level of less than 100 mg/dl. If both diabetes mellitus and vascular disease are present, the LDL cholesterol level in the blood should be less than 70 mg/dl.
The treatment of hypercholesterolemia is therefore based on various pillars:
- Firstly, the individual lifestyle must be improved. This includes sufficient physical exercise, but also a diet low in fat and cholesterol.
- Another pillar of treatment is the elimination of underlying causes: If hypercholesterolemia is caused by a specific medication or disease, for example, the trigger must be specifically treated or eliminated.
- On the other hand, therapy is about eliminating risk factors: for example, high blood pressure must be reduced! In the case of diabetes, blood sugar must be well regulated. Stopping smoking is just as important as abstaining from alcohol. Excessive body weight should also be reduced.
Healthy and “cholesterol-friendly” diet
Daily diet plays a key role in hypercholesterolemia. In some cases, the values improve significantly when those affected change their eating habits. It is important to ensure that you do not consume more calories than your body needs every day, as this can help prevent obesity. The calories contained in fats should make up a maximum of 30% of your total calorie needs.
Also try to cook with low fat and avoid animal fats as much as possible. Animal fats contain high amounts of cholesterol, while vegetable fats are rich in polyunsaturated fats. Cholesterol is therefore only found in animal foods and not in vegetable foods! Foods that are particularly high in cholesterol include offal, chicken egg yolks, fatty pork (for example sausages or bacon), butter, lard, mayonnaise, shellfish and crustaceans, squid and sardines in oil.
If you don't want to switch to a vegetarian diet, you can choose lean and low-cholesterol meats such as game, veal or beef. Trout, cod, pollock and pikeperch are also low in cholesterol.
The focus should therefore always be on a low-cholesterol diet, which means that a maximum amount of cholesterol of 300 mg per day is allowed.
Medical therapy
If all therapeutic measures still do not produce the desired result after several months and cholesterol levels remain significantly elevated, cholesterol-lowering medications must be used.
Various medicinal cholesterol-lowering drugs have different effects:
- Statins (CSE inhibitors)
They are considered the most effective treatment for hypercholesterolemia because they block cholesterol production in the liver. These drugs partially normalize the liver's LDL receptor function. This can lower the LDL level. In the case of familial hypercholesterolemia, it may be necessary to take these CSE inhibitors as early as childhood.
In cases of severe hypercholesterolemia or in cases where treatment with CSE inhibitors (statins) at the required dosage causes too many side effects, other medications may be used. The combination of medications can often reduce cholesterol levels more than the individual active ingredients alone.
These agents include bile acid binders: they bind bile acids in the intestine so that they can then be excreted from the body. This not only removes bile acids, but also the cholesterol they contain.
Bile acid binders alone can reduce cholesterol levels by around 25%. In combination with statins, the treatment success is even greater!
Cholesterol absorption inhibitors (such as the active ingredient ezetimibe) can also be used as additional medication. These medications are intended to prevent the body from absorbing cholesterol in the intestines into the bloodstream.
Cholesterol-lowering procedures of an “extracorporeal nature”
"Extracorporeal" means "outside the body". In particular, the classic treatment consisting of a low-cholesterol diet and cholesterol-lowering medication is not effective against familial hypercholesterolemia, which is inherited from both parents. Therefore, other methods may be considered.
This includes, for example, regular blood washing, a so-called LDL apheresis: This removes the excess LDL from the blood. A special machine to which the affected patient is connected separates unwanted blood components from the excess LDL cholesterol. The "purified" blood is then returned to the body.
Such a treatment procedure takes place at regular intervals, generally every two weeks.
What you can do yourself
A key focus for lowering high cholesterol levels is on changing your personal lifestyle.
Here you can contribute a lot yourself:
- Reduce excess kilos and ensure a healthy body weight.
- Don't eat too much butter! Instead, opt for valuable vegetable oils or diet margarine.
- Be careful of hidden fats in your daily diet. These are often found in some types of cheese, ready meals, sausages or sauces. Fast food is also very high in fat.
- Cook with as little fat as possible. Grilling and steaming are ideal ways to prepare meals and help prevent hypercholesterolemia.
- Eat fresh vegetables and vitamin-rich fruit every day.
- Reduce the amount of cholesterol-rich foods in your daily diet.
- Make sure you have enough fiber and protein. Plant protein in particular can reduce high cholesterol levels. Fiber ensures a long-lasting satiety effect and thus prevents excessive food intake. According to experts, psyllium, oat bran and pectin even have a direct influence on hypercholesterolemia.
However, fiber can weaken or even cancel out the effect of some cholesterol-lowering medications: so be sure to talk to your doctor!
- Avoid alcohol and cigarettes!
- Radical diets are harmful to your body and especially to your metabolism. It is better to change your diet slowly and not suddenly give up all foods. According to experts, frequent and unsuccessful diet attempts can even increase the risk of cardiovascular disease.
- Make sure you get enough sport and activity in your everyday life. You don't have to become a competitive athlete, but moderate exercise in everyday life is the basis for healthy cholesterol levels and a normal body weight.
