7 March 2019 Author: Daniel Beirão Under physiological conditions, cholesterol is present in our body. However, when it reaches high levels, it becomes a risk factor, especially for cardiovascular diseases. So it must be monitored. The determination of the level of cholesterol in the blood, or cholesterolemia, is one of the blood test most requested by doctors in the blood chemistry group. What is cholesterol? Cholesterol is a natural substance, produced by the liver and derived also from the food we eat. In the body, cholesterol has essential and irreplaceable functions, for example: The cell membranes; Certain hormones and vitamins. Therefore, under normal conditions, cholesterol circulates in the blood and is present in all of the body cells. What are “good” cholesterol, “bad” cholesterol and total cholesterol? Cholesterol is not dissolved when it circulates in the blood - it is transported by proteins, which form lipoproteins ; that is, compounds made up of proteins and lipids. The two types of lipoproteins that transport cholesterol are: Low-density lipoproteins (or LDL); High-density lipoproteins (or HDL). LDL and HDL are classified according to the proportion of protein and fat they contain: LDL - about 50% of its weight is cholesterol and 25% is protein; HDL - about 20% of its weight is cholesterol and 50% is protein. Another important difference between LDL and HDL is that the proteins they are made up of are different and have different functions : LDL proteins transport cholesterol to the cells; HDL proteins transport cholesterol to the liver to be broken down and then eliminated. LDL or “bad” cholesterol LDL cholesterol is commonly known as “bad” cholesterol, because high levels in the blood levels are more likely to lead to an increased risk of developing cardiovascular disease. This is because by transporting cholesterol to the cells, LDL contributes to the formation of fat deposits on the walls and inside the arteries. This leads to a reduction in their size and their flexibility - a disease known as atherosclerosis. When the atherosclerosis plaques rupture, a blood clot can form in the inside of the arteries. This clot can completely block the blood flow through the arteries and lead to a myocardial infarction or a stroke (CVA). In a healthy adult, LDL cholesterol should be less than 115 mg/mL . HDL or “good” cholesterol HDL cholesterol , on the other hand, is usually known as “good” cholesterol, because increased levels in the blood are not associated with an increased risk of developing cardiovascular diseases. HDL helps remove cholesterol from the arteries and take it to the liver , where it is broken down and then eliminated. The recommended value for “good” cholesterol depends on gender: More than 40 mg / mL in men; More than 45 mg / mL in women. Total cholesterol Total cholesterol is the sum of LDL cholesterol, HDL cholesterol and 1/5 of the blood triglyceride level. Total blood cholesterol should be less than 190 mg/dL . Triglycerides are also a normal constituent of the body, but high levels of these compounds also appear to be associated with an increased risk of developing cardiovascular disease . Blood triglycerides should be less than 150 mg/dL . What are the problems associated with a high level of cholesterol in the blood? A high level of cholesterol in the blood (i.e. above the limit considered normal) is one of the factors that can increase the risk of certain diseases, including: Myocardial infarction; CVA (stroke). There are other factors that can increase this risk , however, such as: Smoking High blood pressure; Gender (the risk is higher for men); Age (risk increases with age); Family history (the occurrence of these diseases in direct family members at a young age). How can blood cholesterol levels be minimised? The most important cause for excess cholesterol in the blood is food. Sedentary lifestyle, smoking and some hereditary factors also have some contribution. Thus, to control the level of cholesterol in the blood, introduce lifestyle changes, both in terms of food and exercise. The main dietary recommendations are to reduce the intake of red meats, butter, fatty cheeses, cold cuts and precooked foods. Fried foods should also be avoided; Physical activity must be practiced regularly, about 30 to 60 minutes, four to seven days a week; Not smoking and maintaining an adequate and healthy body weight are also goals that should be actively promoted. However, in cases where medical advice and lifestyle changes are not enough, there are drugs that help fight excess cholesterol. Always consult your doctor , who will help you decide which strategy is best to adopt. And remember that prevention is always the best form of treatment . More about the general and family medicine team at Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
