Cholesterol is a type of fat that performs numerous extremely important functions in the organism: it is a constituent of cell membranes, to which it gives the right degree of flexibility and permeability, it represents the basic substance for the synthesis of steroid hormones (aldosterone, cortisone , testosterone, estradiol), vitamin D and bile, a liquid substance produced by the liver, essential for making dietary fats assimilable by the intestine.
Most of the cholesterol necessary for these functions is produced by the organism itself (endogenous production, about 80%), largely by the liver although all the cells of the body are capable of producing cholesterol. A small part, the the remaining 20%, on the other hand, is introduced through foods that contain cholesterol.
Cholesterol, like all fats, is transported in the "organism" inside the blood, in aggregates formed not only by it but also by proteins and other types of fats, such as phospholipids, triglycerides and fatty acids. These aggregates are classified, according to their density, in LDL (from the English low density lipoproteins, low-density lipoprotein) and HDL (from English high density lipoproteins, high-density lipoprotein).
LDLs contain cholesterol that is transported from the liver to the tissues, while HDLs intercept excess cholesterol in the blood, returning it to the liver and thus perform the function of "scavengers", regulating excess cholesterol.
LDLs are dangerous due to their tendency to stick to blood vessel walls and form fatty deposits (plaques). Over time, the plaques can increase in size, closing the blood vessel or partially obstructing it, or they can break off and form blood clots that clog smaller blood vessels.
It is necessary to keep the LDL concentration low and the HDL concentration increase in order to keep the cholesterol level in the blood under control, because high cholesterol levels increase the risk of heart disease and stroke.
Blood cholesterol and diet
A regular, healthy diet accompanied by exercise can help lower cholesterol levels and prevent them from rising.
To lower the level of cholesterol in the blood it is necessary to reduce the intake of saturated fats in the diet by reducing the consumption of:
- foods of animal origin rich in fats, such as fatty meats and offal
- animal seasonings (butter, lard, lard)
Instead, it is advisable:
- eat plenty of fruit and vegetables
- get more fiber, foods of plant origin (vegetables, legumes, fruit, cereals, seed and olive oils) do not contain cholesterol and therefore do not contribute to the "increase in blood cholesterol
If a person has high cholesterol (hypercholesterolemia) he should first adjust his diet and eat healthier. If, despite these precautions, cholesterol levels remain high, the doctor will probably prescribe specific drugs.
Above-normal values may depend on the internal mechanisms of cholesterol production.
Some foods naturally contain cholesterol, known as dietary cholesterol. Foods such as kidneys, eggs and shrimp have a higher cholesterol content than other foods. However, blood cholesterol levels are affected more by the amount of saturated fat in the food than by the cholesterol contained in the food.
If your doctor determines that you need to change your diet to reduce blood cholesterol, the most helpful thing to do is to reduce saturated fat and increase your intake of fruits, vegetables and fiber.
Fiber and cholesterol
Eating fiber helps reduce the risk of cardiovascular disease, and certain fiber-rich foods can help lower cholesterol. Adults should consume at least 30 grams of fiber per day, from various food sources.
Good sources of fiber are:
- wholemeal bread, bran and whole grains
- oats and barley
- fruits and vegetables
- peeled potatoes
- legumes such as beans, peas and lentils
- nuts and seeds
For a good supply of fiber, as well as other essential micronutrients, you should eat at least 5 portions of different fruit and vegetables a day.
Saturated and unsaturated fats
Foods high in saturated fat include:
- fatty meat
- butter, lard and lard
- aged cheeses
- cakes and cookies
- foods containing coconut oil or palm oil
Eating foods that contain unsaturated fat instead of saturated fat can actually help lower cholesterol levels. It is therefore important to replace foods containing saturated fat with small amounts of foods high in unsaturated fat, such as:
- fatty fish, such as mackerel and salmon
- walnuts, almonds and cashews
- seeds, such as sunflower and pumpkin seeds
- vegetable oils, such as olive oil, sunflower oil, corn oil
Trans fats can also raise cholesterol levels. Trans fats can occur naturally in small amounts in some foods, such as those of animal origin, including meat, milk and dairy products.
The trans fats produced by industrial transformations are found in higher concentrations in those foods that have undergone a process of hydrogenation of the fats contained in them to be transformed from unsaturated and liquid, such as vegetable oils, to saturated fats and, therefore, solids, such as margarine.
Trans fats can be contained in some foods which include:
Cooking methods such as frying or roasting also result in an increase in the trans fat content of foods.
Total fat reduction
In addition to consuming a reduced amount of total fat in the diet and replacing saturated fats with unsaturated ones, you can choose lean cuts of meat and low-fat varieties of milk, cheese and derivatives.
The way you cook can also help reduce the risk of consuming excessive amounts of saturated fat. Instead of roasting or frying, other cooking methods can be used:
- steam cooking
- cook in white
- boil and boil
- use the pressure cooker
- cook in the microwave
"Moderate and regular physical activity can help reduce cholesterol levels; physical activity in particular appears to be the most effective method for raising the amount of" good "HDL cholesterol. Physical activity can range from walking to going to bike until you do more vigorous exercises such as running and dancing vigorously.150 minutes of moderate activity each week can improve cholesterol levels.Therefore, moderate long-lasting physical activity (aerobic) would be sufficient to cause an increase in heart rate without causing excessive fatigue.
Products for lowering cholesterol
There are foods that have been suitably modified to make them capable of lowering blood cholesterol. They are mainly derivatives of milk and yogurt in which plant components called sterols and stanols.
The role of these ingredients in helping to lower blood cholesterol has been proven. It depends on their ability to bind to transporters responsible for the absorption of cholesterol from food and its transfer to the blood. However, there is insufficient evidence that they are effective in reducing the risk of heart attack or stroke.
These products may be suitable for people who already have high blood cholesterol (hypercholesterolemia) but do not seem necessary to control optimal cholesterol levels. For this purpose, interventions on diet and physical activity are more effective, as well as less expensive. For some groups of people, including children and pregnant or lactating women, these foods are not suitable. Furthermore, they must be consumed. every day in the right quantity, because taking in excess could be harmful.It is good to remember, however, that they cannot in any way replace a healthy and balanced diet.
There are drugs, statins, that can help lower cholesterol. Some low-dose statins can be purchased at a pharmacy without a prescription. However, if you have high cholesterol levels, you must always contact the treating doctor, the only one capable of deciding the appropriate therapeutic path and monitoring the results obtained over time.
NHS. How to eat less satured fat (English)