What is hypercholesterolemia?
Cholesterol is a very important substance for the correct functioning of our organism: it contributes to the metabolism of fats, to the formation of steroidal hormones and it favors the production of vitamin D which is fundamental for the absorption of calcium.
Cholesterol is transported in the bloodstream by lipoproteins, a particular type of proteins which can be classified based on their "density": low density lipoproteins (LDL) which are bad for our health because they transport the cholesterol synthesized by the liver to the other cells in our body and high density lipoproteins (HDL) which remove the excess cholesterol from the various tissues in our body and transport it back to the liver which in turn expels it.
When the total levels of cholesterol (LDL + HDL) are higher than 200mg/dl, we are witnessing a case of hypercholesterolemia: the excess cholesterol tends to build up inside the arteries forming atherosclerotic plaques which can, in time, obstruct the veins and block the blood flow to the heart causing heart attacks and other cardiovascular pathologies.
What causes hypercholesterolemia?
In most cases, hypercholesterolemia is caused by a dietary regime which is too rich in fats and condiments: these foods are particularly rich in cholesterol. Hypercholesterolemia may also be linked to certain physiological conditions such as pregnancies and menopause and it may also be linked to certain hepatic pathologies, chronic renal deficiency and hyperthyroidism. Obesity, diabetes and sedentary lifestyles are also known as risk factors which may induce the insurgence of hypercholesterolemia. There is also an important genetic and hereditary component.
Can we prevent hypercholesterolemia?
Patients with hypercholesterolemia often are unaware of it because this alteration does not have direct symptoms. Because of this, cholesterol must constantly be monitored by means of a simple blood test.
Prevention is the main strategy in order for us to keep our cholesterol at normal levels and this starts with focus on our eating habits. Adopting a diet based on a limited intake of animal fats (such as fatty meats, dairy products, eggs) and on the intake of vegetables and olive oil is a good idea. Other preventive measures include adopting a healthy lifestyle which means exercising (because it increases the levels of HDL), avoiding smoke (because it lowers the levels of HDL) and limiting the intake of alcoholic beverages.
What is cholesterol?
Cholesterol is a fat substance which is necessary for the correct functioning of the organism: it takes part in the synthesis of certain hormones and of vitamin D and it constitutes cellular membranes. It is produced by the liver and it may also be introduced into the organism through our diet: it is contained in foods rich in animal fats (meat, butter, cold cuts, cheese, egg yolk, liver). It is not contained in fruits, vegetables and cereals. Cholesterol is transported in the bloodstream by a specific type of particles: lipoproteins. There are 4 types of lipoproteins and these are classified based on their density which is in directly opposite proportion to the present quantity of cholesterol. The most important lipoproteins for cardiovascular prevention are:
- LDL (low density lipoproteins): they transport synthesized cholesterol from the liver to the organism’s cells,
- HDL (high density lipoproteins): they remove the excess cholesterol from the organism’s tissues and transport it back to the liver which then eliminates it.
Hypercholesterolemia and its consequences on the patient’s health
LDLs (low density lipoproteins) are known as "bad cholesterol": when there are too many in the organism, they tend to build up on the arterial walls, causing their progressive thickening and hardening. This process, known as atherosclerosis, may cause the formation of plaques (atheroms) which are an obstacle to the correct flow of blood and which may completely stop the blood folw. When the heart does not receive enough blood rich in oxygen, angina pectoris may occur. This condition is characterized by chest pain, pain in the upper limbs and in the jaw. Angina pectoris usually occurs in cases of excessive physical efforts or in cases of excessive stress. The plaques may also detach from the arterial walls and form clots which may cause a sudden blockage in the blood flow. Based on where the clot is situated, the obstruction of a blood vessel may cause a myocardial infarction, a cerebral ictus or claudicatio intermittens in the lower limbs.
Hypercholesterolemia occurs when the total cholesterol (LDL + HDL) is too high.
The ideal values of cholesterol are as follows:
- total cholesterol: up to 200 mg/dl 100-190,
- LDL cholesterol: up to 100 mg/dl <150,
- HDL cholesterol: higher than 50 mg/dl. >35.
Symptoms and diagnosis
Elevated levels of cholesterol do not produce direct symptoms: many people are unaware of the fact that they have hypercholesterolemia. Nonetheless, cholesterol may be easily measured with a simple blood test and it needs to be constantly monitored.
Genetic inheritance and risk factors
Many risk factors may contribute to hypercholesterolemia. Among these are our dietary habits, obesity and excess weight, lack of physical activity, metabolic diseases (such as diabetes). Smoking can also damage the blood vessels and accelerate the hardening of the arteries. Moreover, the LDL level increases with age, especially in women.
Certain individuals are genetically prone to developing hypercholesterolemia and they may subsequently develop atherosclerosis and cardiac problems even as young adults. This condition is known as hereditary hypercholesterolemia and it is connected to a series of mutations in the receptive gene of LDLs which is situated in chromosome 19. This disease is characterized by elevated levels of total cholesterol and of LDL cholesterol (but not of triglycerides) with a variable level of severity based on the number of mutations. In its homozygote form, this disease appears to be significantly severe since birth: plaques (xanthomas) develop in the inner elbows, on the knees and buttocks, cholesterol deposits appear on the skin, tendons and around the cornea. Moreover, the levels of total cholesterol are in a range between 600 and 1200 mg/dL. Heterozygote individuals show milder symptoms which may be hard to find during the first years of patients’ lives. The problems affecting the cardiovascular system start to show around 35-40 years of age in men and around 45-55 years of age in women.
Nowadays a pharmacological therapy exists and it is able to cure hereditary hypercholesterolemia and its long term cardiovascular consequences. Individuating and diagnosing this disease as soon as possible become significantly important. The presence of elevated levels of total cholesterol is a fundamental condition for the correct diagnosis of this disease but other individual and environmental factors need to be taken into consideration. In fact, other forms of hypercholesterolemia exist and we must also consider the fact that an increase in the levels of cholesterol may also be the consequence of other diseases and pathologies. It is therefore important to proceed with a genetic and molecular diagnosis of the disease because this procedure offers an accurate and early stage diagnosis of the pathology even before the individual is born.
Prevention and treatment
Prevention is the best strategy an individual can adopt in order to keep his/her cholesterolemia within the suggested levels. The recommended lifestyles and habits are:
- a healthy diet with a reduced intake of fats (especially saturated fats) and alcohol,
- monitored body weight,
- regular physical activity,
- no smoking.
Sometimes, changing a lifestyle habit is not sufficient and a pharmacological therapy may be a better option. There are several categories of cholesterol-reducing therapies:
- statins: they slow down the production of LDL cholesterol and increase the liver’s ability to eliminate the LDL cholesterol which is already present in the organism. They are selective inhibitors of the 3-hydroxy-3-methylglutaryl-coenziam A HMG-CoA-reductase, an enzyme which catalyses the initial stage in the bio-synthesis of intracellular cholesterol. A reduction of intracellular cholesterol through an up-regulation mechanism increases the expression of LDL receptors and allows the LDL to be eliminated;
- acid bile reducers: they are bonded with the cholesterol contained in the acid bile in the intestines and are eliminated with the feces. This way they lower the level of LDL cholesterol;
- niacin (nicotinic acid): it lowers the levels of total cholesterol and of LDL cholesterol (including triglycerides) and helps increase the level of HDL cholesterol;
- fibrates: they are generally used to lower the levels of triglycerides and, in certain cases, to increase the levels of HDL cholesterol.
These prescription drugs may have side effects and must be prescribed and monitored by a physician.
These prescription drugs are provided by the Italian National Healthcare System if the patient fits into one of the categories indicated in Note 13; only patients affected by one of the following conditions may benefit from these prescription drugs as provided by the national healthcare system:
- hereditary dyslipidemia;
- hypercholesterolemia (cases that cannot be cured by means of a specific diet) in patients with an elevated risk of cardiovascular events (10 year risk > 20% based on the Charts or on the Progetto Cuore Risk Algorithm elaborated by the Italian National Health Institute) (primary prevention) and in patients with documented coronary diseases or with previous ictus conditions or with peripheral obliterating coronary disease or infarctions or diabetes (secondary prevention);
- previous cases of myocardial infarction;
- hyperlipidemia (cases which cannot be cured by means of a specific diet) induced by prescription drugs (immunosuppressants, antiretrovirals, aromatase inhibitors) or in patients with chronic kidney failures.
Fermented red rice
Prescriptions drugs aren’t always necessary for the treatment of cholesterol, especially when there are no other cardiovascular risk factors. Often the use of food supplements in combination with a correct diet and physical activities is enough to reduce the levels of cholesterol. For example, fermented red rice is one of the most commonly used natural substances in the treatment of hypercholesterolemia. It is obtained from the fermentation of common rice (Oryza sativa), by a specific yeast (Monascus purpureus – red yeast). This rice owes its name to its characteristic red coloring and it is a traditional substance used in Chinese phytotherapy. It is also known in Western civilizations for its lipo-reducing qualities. During the fermentation, the red yeast is enriched by a group of substances (monacolins) with a specific cholesterol-reducing activity. Among these, monacolin K is the most important one.
The integration of fermented red rice in the patient’s diet has proven to be important for the normalization of the levels of total cholesterol and of triglycerides.
Another characteristic of fermented red rice is its ability to reduce cardiovascular risks thanks to other anti-atherosclerotic actions (anti-inflammatory, vasodilatating, lipoprotein A reducing). Moreover, as opposed to synthesis statins, fermented red rice poses no side effects such as: muscular problems (ranging from muscular fatigue to cramps and mialgia), proteinuria, hepatho-toxicity, dyspepsia and, more rarely, nausea, migraines.