Immune functions have been shown to be impaired by malnutrition and starvation, aging, physical and mental stress, and exposure to harmful environmental factors.


Nutrition is the basis for good health. It is not the only, but it is an extremely important factor in maintaining the body's immune system. Nutrition affects the immune system in two ways:

  • The activities of the immune system can cause impaired nutritional status as a result of increased nutritional needs for protein, minerals and vitamins;
  • Changes in dietary intake affect the intensity of the various activities of the immune system.



If we have knowledge of how to eat and follow the recommendations of dieticians, we can significantly reduce the risk of viral and bacterial diseases in winter. As banal as it sounds, the main thing is to follow the principles of a healthy balanced diet. Although most people are familiar with the rules of healthy eating, the recommendations of experts are often ignored.


The classic principles of nutrition are the basis of modern healthy eating. One should eat in moderation, but with a wide variety of foods.

 

There is no food or group of foods that can supply all the nutrients our body needs.


We should eat cereals, fruits and vegetables, protein-rich foods - meat, eggs, fish or their plant alternatives - legumes (beans, lentils, soy). Milk and dairy products should not be restricted, and it is advisable to emphasize low-fat products.


It is advisable to limit the amounts of fats of animal origin, as well as sugar-rich foods and beverages.


Adherence to the principles of healthy eating is necessary in every season, but it is especially important in winter, as it creates the basis for maintaining good immunity. A balanced diet reduces the risk of nutritional deficiencies in the body, which create a prerequisite for lowering immunity.


Some foods have a special relationship with our immune system. Such are protein foods and those rich in vitamins and minerals. Vitamin C, B vitamins, some minerals such as zinc and magnesium are involved in the functioning of the immune system.


Strict and restrictive diets should not be followed, especially during the winter season, when the risk of viral infections is increased. Of course, a healthy weight is the basis for good immunity. Both underweight and overweight and obesity impair immunity. Obese people are more likely to suffer from respiratory diseases and show a higher risk of infections during surgery. Obesity has been found to reduce the response of both T and B lymphocytes.


Measures should be taken when a person is overweight but severely restrictive diets are not appropriate. Protein-energy deficiency disrupts most of the defense mechanisms, even when it is moderate. It has a special effect on T lymphocytes, which leads to a decrease in their number.


More fruits and vegetables should be consumed. In winter, citrus fruits rich in vitamin C are available. It is best to eat seasonal fruits and vegetables that have a stored vitamin content. When a fruit or vegetable is plucked green and has not reached its maturity, or is grown in a greenhouse, it has a reduced amount of vitamins. If the fruits are picked in the fall, such as apples, for example, during storage, the level of vitamin C is constantly decreasing. Currently, seasonal vegetables that are extremely useful are cabbage, beets, carrots.


It has been shown that the immune system is affected by energy intake from food and fat levels. High energy intake disrupts the response of lymphocytes - important protective cells of the immune system. On the other hand, the high fat content of food suppresses the functions of other major immune cells - T cells and natural "killer" cells. It has been found that the capacity of killer immune cells is increased when fat intake is reduced from 32% of the energy value of food to 22%. What matters is not only the amount but also the type of fat. The n-6 polyunsaturated fatty acids contained in sunflower oil stimulate the production of cytokines - substances that are released by macrophages and other immune cells in response to viral or bacterial infection. Although, that cytokines are important for the normal functioning of the immune system, they play a major damaging role in inflammatory processes when formed in large quantities. However, fish oil is rich in long-chain omega-3 fatty acids, which suppress the release of cytokines and reduce their inflammatory action.