Immune System

The immune system is the body’s defense mechanism that recognizes and responds to substances (antigens) that are different from its own tissues, aiming to eliminate them. Immunity, the ability of the body to protect itself against foreign substances, is the term used to describe this process. The science that studies the mechanisms within the immune system is called immunology.

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Immunity, also known as immunization, refers to the body’s ability to recognize and respond to substances (antigens) that are different from its own tissues in order to eliminate them. Immunology is the scientific study of the mechanisms within the immune system.

The immune response consists of two main components: the specific response and the non-specific increase in the effectiveness of this response. Upon encountering a specific antigen for the second time, the immune response in individuals is much more effective and rapid. This mechanism is fundamental in preventing the recurrence of certain infections or providing protection through vaccination.

The immune response can be divided into cellular and humoral types. Cellular immunity involves lymphocytes, monocytes, macrophages, natural killer cells, antigen-presenting cells, while humoral immunity involves immunoglobulins (secretory immunity). Both mechanisms work together to form the immune response.

Immunodeficiencies, which can occur in cellular, humoral, or both types of immunity, are investigated, and their locations are determined for appropriate treatment. Detecting and treating these deficiencies is within the scope of the science of immunology.

When the immune system is compromised, certain indications may provide clues to potential issues, such as:

– More than 8 infections in one year
– More than 2 serious sinus infections in one year
– More than 2 pneumonias in one year
– Growth and developmental delays
– Recurrent soft tissue or deep tissue (organ) abscesses
– Fungal infection in the mouth or on the skin in children over one year old
– Need for intravenous (IV) antibiotics to correct infections
– Prolonged ineffective use of antibiotics for more than two months
– Family history of primary immunodeficiency

In addition, when examining these children for immunodeficiency syndromes, specific signs related to that condition are sought. The causes of immunodeficiency diseases can include genetic predisposition, environmental factors, chromosomal abnormalities, malnutrition and vitamin deficiencies, or infections.

It’s important to note that allergic diseases should not be confused with immune deficiencies when discussing the immune system. Allergy is defined as an exaggerated immune response, while atopy is the genetic predisposition to develop allergic responses. Allergic reactions occur as a result of the immune system’s response to environmental antigens (dust, pollen, grass, etc.) that it should normally tolerate. Allergic diseases are prevalent in today’s society, and when investigating the causes of these diseases, genetic predispositions and environmental factors are often blamed. The increasing prevalence of allergic diseases in developed societies is attributed to factors such as strict hygiene practices, small family structures, sterile food consumption, and improved health services. It is suggested that these factors disrupt the natural balance and negatively impact human health.

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The immune system is not only limited to responding to external factors but can also create autoimmune diseases where self-tolerance is disrupted against its own tissues. These include systemic lupus, rheumatoid arthritis, atopic dermatitis, asthma, and various types of cancer. These diseases, which can be prevented with substances supported by scientific studies that can turn the immune response in favor of the body and limit exaggerated inflammatory responses, are now very popular and referred to as immune nutrition. Among these substances are probiotics, prebiotics, synbiotics, trace elements (zinc, selenium, iron, copper), omega-3 and omega-6 fatty acids, nucleotides (arginine, glutamine, branched-chain amino acids), and vitamins.

There is a very close relationship between the immune system and nutrition. In recent years, the goal of proper nutrition has shifted beyond meeting protein and energy requirements to enhancing disease resistance with the nutrients consumed, limiting or stopping the response of the body to its own tissues influenced by environmental and genetic tendencies. Omega-3 and 6 fatty acids, which have been emphasized the most, play a crucial role in the development of the human nervous system and the retina layer of the eye. Breast milk is rich in omega-3 and 6 fatty acids, and exclusively breastfeeding infants in the first six months supports the immune system from the early stages of life. Omega-3 and 6 fatty acids regulate the responses of lymphocytes and natural killer cells, which are essential functions in the immune system, and limit inflammation. It is known that immune nutrition can prevent diseases such as coronary heart disease, autoimmune diseases, colon cancer, breast cancer, and hypertension.

Probiotics balance the number of beneficial microorganisms in the intestine when taken with food, positively affecting health. Lactobacilli, bifidobacteria, and yeasts are the most well-known among them. Probiotics are also referred to as live drugs today and are abundant in breast milk. Probiotics contribute to the immune system by enhancing the activity of macrophages, cytokine production, immunoglobulin formation, and natural killer cell activity. Hence, infants fed with breast milk experience fewer episodes of diarrhea. Probiotics are particularly effective in the gastrointestinal system, and they can be used to address conditions such as infectious diarrhea, lactose intolerance, food-related allergic reactions, atopic dermatitis, constipation, hypercholesterolemia, ulcerative colitis, and colon cancer. Probiotics must be live and taken externally. Lactobacillus GG is the most commonly used. These microorganisms produce lactic acid in the intestines, preventing the proliferation of pathogenic microorganisms. They increase secretory IgA (immunoglobulin secreted from the intestinal surface) levels in children, stopping the activities of agents causing diarrhea such as rotavirus. Additionally, they suppress the immune response in favor of the body by preventing the secretion of cytokines (secretory substances) that play a role in food allergies. The intestinal surface is known to be 100 times larger than the outer body surface, and regulating the intestinal flora is crucial for the development of the immune system. In the past, the regulation of the intestinal flora was achieved through the consumption of fermented products (such as yogurt or kefir). However, today, we are consuming one-millionth of the probiotics our ancestors took daily, a situation well explained by the shift in current dietary habits towards refined foods. Prebiotics are non-living and are selective for beneficial microorganisms in the colon, aiding in their proliferation. Fructans (inulin, oligofructose), soybean oligosaccharides, and galactooligosaccharides are among them. Oligofructans are abundant in wheat, garlic, onion, leeks, asparagus, artichoke, banana, and breast milk. Synbiotics are substances taken orally that contain both probiotics and prebiotics. It has been understood that they are more effective than using probiotics or prebiotics alone.

In today’s world, probiotics and prebiotics are used for supportive purposes in:

Individuals who do not consume the desired amounts of vegetables and fruits,
Individuals with suppressed immune systems,
Patients in intensive care units,
Premature and newborn infants,
Treatment of lactose intolerance and diarrhea,
Reducing the symptoms of allergic diseases.

The best clinical response to probiotics has been obtained in cases of food-allergic atopic dermatitis during childhood. However, a positive effect has not yet been demonstrated on asthma and allergic rhinitis. Although very few undesirable side effects have been reported, attention should be paid not to administer food and drugs containing probiotics to individuals with immune deficiencies, especially. Although positive responses to probiotics are expected in children with food allergies and atopic dermatitis, it should not be forgotten that probiotics are not yet included in the current treatment protocols.

Trace elements such as zinc, selenium, and iron, which cannot be produced in the body and need to be taken externally, are cofactors that activate enzymes playing a role in the functioning of the immune system. Selenium is necessary for maintaining the integrity of the cell membrane, and zinc is required for the functionality of enzymes that act as building blocks for structures like DNA and RNA. Zinc deficiency results in impaired cellular immunity, disruption in skin integrity, frequent recurring diarrhea, and growth retardation. Antioxidants neutralize oxidizing substances that cause damage to tissues and organs during the formation of metabolic events in the body. Enzymes playing a role in this neutralization, i.e., inactivation (e.g., glutathione peroxidase), are dependent on selenium, zinc, copper, manganese, vitamins E, C, D, and tocopherol. Antioxidants and vitamins are abundant in fresh fruits and vegetables. Omega-3 fatty acids are found in salmon, tuna, walnuts, hazelnuts, wheat, purslane, spinach, and broccoli. Iron is found in red meat, dark green leafy vegetables, legumes, and dried apricots. Zinc is abundant in meat, fish, cereals, walnuts, and almonds.

Finally, in addition to the natural immune system, it is necessary to mention acquired immunity (secondary immunity) achieved through vaccination. Vaccination is the most important medical practice in the world contributing to the improvement of child health after the use of clean water. The goal of vaccination is to create long-term memory in the immune system. Thus, vaccination prepares the body for frequently encountered agents, reducing the vitality or disease-causing effects of microorganisms and their secreted toxins by creating memory in the immune system, in other words, protecting individuals against these diseases.

In conclusion, to support the immune system of our children:

Breastfeeding for the first six months,
Protecting against preventable diseases through vaccination,
Increasing the consumption of fresh fruits and vegetables and keeping away from refined foods,
Supporting nutrition with pro and prebiotics,
Introducing them to a less sterile environment, exposing them to the outside world more, are simple but very important practices with potential benefits that we can observe.


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İKİNCİOĞULLARI, A. (2010). Allergic Diseases. In: Basic

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