The immune system is our defense system, it fights viruses, fights bacteria, fungi and kills parasites and tumor cells. You can watch over your immune system and help it, thanks to a few simple gestures and habits to be in top shape.
- 1 The immune system in general
- 2 organs of the immune system
- 3 The stages of the immune response
- 4 The non-specific immune response
- 5 Inflammation is protection
- 6 The specific immune response
- 7 The importance of lifestyle
- 8 Factors that decrease the effectiveness of the immune system
The immune system in general
The immune system is essential to our survival. It is made up of several organs, and ensures its presence everywhere in the body, at any time of the day and night. What is it made of? How does it work?
organs of the immune system
The immune system is made up of complex interactions involving many different organs, cells and substances. The majority of cells are not found in the blood, but rather in a collection of organs called lymphoid organs.
Bone marrow and thymus. These organs make immune cells (lymphocytes).
Spleen, lymph nodes, tonsils and clusters of lymphoid cells located on the mucous membranes of the digestive, respiratory, genital and urinary tracts. It is usually in these peripheral organs that the cells are called upon to react to an attack.
The speed of action of the immune defenses is extremely important. This is based, among other things, on the effectiveness of communication between the various actors involved. The blood system is the main passageway that connects the lymphoid organs.
Although we cannot yet explain all the mechanisms, we now know that there are important interactions between the immune system, the nervous system and the endocrine system. Certain secretions of immune cells are comparable to hormones secreted by the endocrine glands, and the lymphoid organs have receptors for nervous and hormonal messages.
The stages of the immune response
There are two main types of immune response:
On the one hand, the non-specific response, which constitutes “innate immunity” (so named because it is present from birth), acts without taking into account the nature of the microorganism that it fights. ;
The second, the specific response which involves recognizing the agent to be attacked and storing this event in memory: this is “acquired immunity”.
The non-specific immune response
The first line of defense
The skin and mucous membranes are the first natural barriers against attackers. The skin is the largest organ in the body and offers very effective protection against infections. It offers a hostile environment for microbes: its surface is slightly acidic and rather dry, and it is covered with “good” bacteria. This explains why excessive hygiene is not necessarily a good thing for your health.
The mouth, eyes, ears, nose, urinary and genital tracts still provide passageways for germs. These routes also have their protection system. For example, cough and sneeze reflexes expel microorganisms from the airways.
Inflammation is protection
Inflammation is the first barrier encountered by pathogenic microorganisms that cross our body envelope. Like the skin and mucous membranes, this type of immune response acts without knowing the nature of the agent it is fighting. The purpose of inflammation is to inactivate the aggressors and to initiate tissue repair (in the event of damage). Here are the main stages of inflammation.
The vasodilation and greater permeability of the capillaries in the affected area have the effect of increasing the blood flow (responsible for the redness) and allowing the arrival of the actors of the inflammation.
Destruction of pathogens by phagocytes: a type of white blood cell that is capable of engulfing pathogenic microorganisms or other diseased cells and destroying them. There are several types: monocytes, neutrophils, macrophages and natural killer cells (NK cells).
The specific immune response
This is where lymphocytes come in, a type of white blood cell which can be divided into two classes: B lymphocytes and T lymphocytes.
B cells account for about 10% of the lymphocytes circulating in the blood. When the immune system encounters a foreign agent, the B lymphocytes are stimulated, multiply and begin to produce antibodies, this is the starting point for the destruction of the pathogen.
T cells represent more than 80% of circulating lymphocytes. There are two types of T cells: cytotoxic T cells, which when activated directly destroy virus-infected cells and tumor cells, and facilitative T cells, which control other aspects of the immune response.
The specific immune response creates acquired immunity, which develops over the years as a result of encounters our body has with specific foreign molecules. Thus, our immune system keeps in memory the particular bacteria and viruses that it has already encountered in order to make the second reaction much more effective and rapid. It is estimated that an adult has in memory 109 to 1011 different foreign proteins.
The importance of lifestyle
A person who shows signs of immune weakness, or who wishes to better defend himself against common ailments, should first and foremost look into his lifestyle. Indeed, epidemiological data indicate that diet, smoking, sleep, physical activity, stress level, quality of social relationships and the environment are all elements that influence the immune system.
Factors that decrease the effectiveness of the immune system
Major malnutrition with calorie and protein deficit is the most important cause of immune deficiency. Adequate calorie and protein intake depends on sex, age, height and energy expenditure. In developed countries, another type of nutritional deficiency is increasingly observed: micronutrient deficiency, which means vitamin and mineral deficiency. The popularity of “junk” type foods partly explains this phenomenon. Micronutrient deficiency is, moreover, common in the elderly, who often have a poor appetite and less varied diet, as well as in people with diabetes, due to their disease and the medications they must take to treat it. . Animal studies show that a deficiency in just one of the following micronutrients could affect immune function: zinc, selenium, iron, copper, calcium, folic acid or vitamins A, B6, C and E2.3.
– Regular consumption of foods low in vitamins and minerals.
– Abuse of foods high in sugar (it seems that 50 g of sugar per day is a reasonable maximum, and this includes sugar from fruit).
– Consumption of foods that cause allergies.
– Abuse of foods high in saturated fat.
– Considerable alcohol abuse (the effect of moderate consumption is not known).
In addition, there are also:
Aging. Age is a factor in the weakening of the immune system. Although some people age healthy, studies show that infections, inflammatory diseases and cancer are more common in people over the age of 65.
Physical inactivity, and conversely, overtraining of athletes.
Lack of sleep.
The stress. Under stress, the adrenal glands secrete cortisol and the sympathetic system, norepinephrine – two substances that weaken the immune system.
Exposure to toxins, including the use of chemical household cleaners and herbicides on lawns, and the consumption of fruits and vegetables sprayed with insecticides.
Exposure to outdoor air pollutants as well as those that spread inside homes (mold, bacteria, tobacco and combustion gases).
Presumably obesity. Obese people are more susceptible to infections, but the cause cannot be explained.
positive behaviors to strengthen the immune system
Here are some of the lifestyle habits that provide the best chance of maintaining a strong immune system.
Eating habits favorable to immunity
– Adequate calorie and protein intake.
– Five to eight glasses of water a day.
– Sufficient consumption of fruits and vegetables as fresh as possible, whole grains, legumes and good fats.
Interestingly, the results of epidemiological and clinical studies indicate that the regular consumption of alliums (garlic, onion, leek, shallot, chives) reduces infections and the incidence of different types of cancer.
Moderate physical activity
We know the multiple health benefits of regular physical activity: better cardiovascular fitness, good maintenance of muscle mass, normalization of blood pressure, weight control and reduction of several associated risk factors. to chronic diseases. In addition to supporting immunity by promoting overall good health, exercise may also have a direct effect on immunity. First, by improving blood circulation, it is believed that cells and other substances of the immune system can flow through the body more easily.
Without a doubt, stress has a detrimental effect on health. Researchers interested in the link between stress and immunity do not dwell on one-off, short-term stresses, but rather on frequent and constant stresses (for example, juggling the demands of work and family life or caring for a sick relative). Chronic stress causes the release of stress hormones, such as cortisol. There are many relaxation tools that help get through a more stressful episode in life. These include meditation, somatic education and oriental disciplines (Qi Gong, tai chi, yoga).