Cholesterol is a vital structural component of every cell in the human body and plays a key role in functions such as hormone production. Over the years, however, there is a price to pay for high cholesterol. Atherosclerosis is the build-up of fatty plaque inside the arteries, which can increase the risk of serious conditions such as a heart attack or stroke. Prof. Steinhagen-Thiessen, M.D., senior professor at the Department of Endocrinology and Metabolic Medicine at the Charité Universitätsmedizin Berlin, explains what cholesterol is and why high levels can be dangerous.
The Role of Cholesterol
Cholesterol is a fatty substance found in the blood that is vital to us humans. Our body needs it for the production of bile acids, cell membrane building, hormone and vitamin D production, and many other important processes in human tissue. It is produced mostly in the liver and can be found in every cell in the human body.
Roughly 70% of the body’s existing cholesterol is synthesized by the body itself, with the remaining 30% coming from food. As important as cholesterol is, there are various circumstances that can lead to too much of it in the blood, which can have negative health consequences.
If too much cholesterol is permanently present in the blood stream, it can stick to the inner walls of blood vessels. This leads to fatty deposits – called plaques – that may cause blood vessels (such as arteries) to become narrower over the years. This reduces blood flow and can subsequently cause myocardial infarction (heart attack), stroke, and bleeding disorders.
The Two Types of Cholesterol
There are two types of cholesterol: HDL cholesterol and LDL cholesterol. HDL cholesterol (High-Density Lipoprotein cholesterol) is commonly referred to as “good” cholesterol. High HDL levels are a good sign and they should usually be at least 40 mg/dL.
HDL cholesterol transports bad cholesterol from blood vessels back to the liver, helping reduce the risk of heart disease.
The “bad” LDL cholesterol (Low-Density Lipoprotein cholesterol) creates the plaques on the walls of the arteries, a process known as atherosclerosis. The LDL cholesterol levels should therefore be as low as possible. In healthy people who do not have a risk factor for cardiovascular disease, the LDL cholesterol level should be below 115 mg/dL.
In those who have a history of cardiovascular conditions, such as a heart attack or stroke, levels should not exceed 70 mg/dL. In this case, it is particularly important that you know your LDL cholesterol levels.
The 3 causes of high cholesterol
There are three main causes for high cholesterol levels. These include age, nutrition and, above all, family disposition – high cholesterol can therefore be hereditary.
1. Familial hypercholesterolemia
Very high LDL cholesterol levels, which in some cases lead to the development of arteriosclerosis at a young age, are usually due to a familial disposition. Mutations in the DNA that leads to this hereditary fat shedding disorder are usually responsible. In familial hypercholesterolemia (high cholesterol), there are no or few receptors for the cholesterol molecule on the cell surface that can receive LDL cholesterol from the blood into the cells. As a result, more LDL cholesterol deposits in the vessel walls and causes the vessels to constrict.
It is important to know that the disease is always passed on and no generation is left out. This means that for a family of four children and one parent with the associated genetic cholesterol disorder, statistically, two out of four children will also have high cholesterol levels. This is also called heterozygous form.
In particularly severe, so-called homozygous cases, the child inherits the gene mutation from both parents, whereby the cholesterol level can be extremely high. In this case, LDL cholesterol may range between 400 mg/dL and 1,000 mg/dL - two to ten times higher than normal. These extreme values can lead to a heart attack in adolescence. If the disease is known to the parents, it is therefore essential to check the level of cholesterol in children as early as possible in order for effective treatment to be provided.
The level of LDL cholesterol can vary greatly from individual to individual. In most cases, there is a genetic predisposition. Often, an unhealthy lifestyle (diet, smoking, lack of exercise etc.) is added to genetically-induced elevated cholesterol levels, further adversely affecting the level of LDL cholesterol. In addition, the overall risk of cardiovascular disease is increased by additional risk factors, such as high blood pressure, a sugar disease, obesity or similar.
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2. High LDL-Cholesterol Diet
Although food is only responsible for 30% of total cholesterol in our body, diet is an important factor in high cholesterol. It is estimated that in 40% of cases of high cholesterol, lifestyle alone is responsible. An unhealthy diet consisting of lots of fat and too little healthy food like vegetables, fruits, and fiber causes LDL cholesterol to rise.
Certain foods have a particularly negative effect on cholesterol levels. These include animal fats, red meat, sausages and many packaged meals. Overconsumption of such food leads to so-called downregulation of LDL cholesterol receptors. This means that the number of LDL cholesterol receptors on the surface of the cells decreases, allowing less LDL cholesterol to be bound and removed from the bloodstream. The excess cholesterol remains in the bloodstream, circulates there, is oxidized and deposits on the vessel walls.
As you get older, the risk of LDL cholesterol increases as well. As you age LDL receptors are increasingly lost, which in turn means that the LDL cholesterol is no longer taken up from the blood and processed, but deposited in the vascular walls.
It has been observed that LDL cholesterol increases equally in age in women and men, with the decisive difference that, in women, LDL cholesterol levels until menopause are significantly lower than in men of the same age. However, the moment that women enter menopause and the estrogenic effect on LDL cholesterol diminishes, the cholesterol level rises abruptly. This is also the reason why, statistically, coronary heart disease and heart attacks occur seven to ten years later in women than men.
Since high cholesterol does not initially trigger any symptoms, it is strongly recommended that cholesterol levels are checked regularly at so that appropriate measures can be taken early on if necessary. By switching lifestyle – possibly in combination with medications – the risk of cardiovascular diseases such as heart attack, coronary heart disease, stroke, etc. caused by high cholesterol can be reduced.
High cholesterol and the consequences
A high cholesterol level is considered to be one of the most important risk factors for the development of cardiovascular disease, the number one cause of death worldwide, in addition to smoking, high blood pressure, diabetes, obesity, and physical inactivity.
Without appropriate therapy, high cholesterol can lead to arteriosclerosis. This develops unnoticed over years and decades. Deposits form in the vessel walls – plaques consisting of cholesterol – causing the blood vessels to narrow and lose their elasticity. This can have severe consequences.
If plaques are deposited in the coronary arteries, this impairs blood flow and the heart can no longer be supplied with a sufficient quantity of oxygen and nutrients. The result can be angina pectoris, symptoms of which can include an oppressive tightness in the chest, dull or stinging pain, and shortness of breath.
In addition, if the deposited plaques rupture, a blood clot may form which completely blocks the coronary vessels, resulting in a heart attack. This can also be triggered by a partial closure of a vessel; blood vessels are blocked by more than 75% in only 1 in 6 heart attack cases.
Atherosclerosis in arteries that oxygenate the brain can lead to an ischemic stroke. Another effect of arteriosclerotic vascular calcifications may be circulatory disorders in the legs and pelvis. In peripheral artery disease, severe pain in the leg muscles often occurs during walking.
To prevent the effects of atherosclerosis, you should have your cholesterol level checked regularly, especially LDL cholesterol. If your scores are too high, talk to your doctor about appropriate therapy. With a change in dietary habits, LDL cholesterol can be lowered by about 10-15%. Through regular exercise you can again influence 5-10% of your LDL cholesterol. If necessary, the benefits of lifestyle changes can be supplemented by additional medication to help achieve the right level of LDL cholesterol.
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