Our body is self-sufficient in terms of guarding us against any potential disease or infection. It is equipped with a robust shield in the form of an immune system. Immune system acts as an effective defense system against potentially harmful foreign bodies and diseases. Major components of the human immune system include organs like bone marrow, thymus, spleen, adenoids, lymph vessels and lymph nodes. Some type of cells like B cells, T cells, dendritic cells, macrophages, natural killer cells, granulocytes also play a key role in the immune system. Healthy immune system identifies a majority of the health threats that come from the invasion of parasites, viruses, or bacteria. Immune system has to differentiate between the types of foreign bodies and then fight against them. Therefore, a strong immune system demands a balanced source of nutrition for optimum functioning.
Nutrition plays an important role in maintaining a strong immune system.For optimum functioning and health, the immune system demands substantial energy and nutrient requirements. Our body fulfills the nutrient requirement through the daily diet.
Proteins Amino acids constitute the basic units of protein. Amino acids like arginine, glutamine, and cysteine are the key players of immunity. They are critical components in pathological and physiological processes. Amino acids are essential in generating an immune response and maintenance of the immune system. These micronutrients produce antibodies, regulate the activation of natural killer cells, macrophages, Tlymphocytes and B-lymphocytes, gene expression, lymphocyte proliferation and cellular redox reaction.
Glutamine Glutamine is a key requisite for optimal lymphocyte proliferation and creation of cytokines by macrophages and lymphocytes. Macrophage mediated phagocytosis is influenced by glutamine availability.
Cysteine It is essential for T cells, as it is a progenitor of tripeptide glutathione.
Arginine Depletion of arginine could suppress the proliferation of T cell and impair T cell functions.
Vitamins Vitamins are essential for performing various functions in our body. One of the essential functions of vitamins is boosting the immune response towards pathogens. They are required in appropriate amounts in our daily diet. However, if these are not consumed in suitable quantities, could deplete its concentration, thereby leading to unwanted health conditions. Most of the vitamins perform cellmediated response by assisting in the secretion of cytokines and Tlymphocytes. Therefore, regular supplementation of dietary vitamins in optimum quantities could support the immune system and enhance the immune response.
Vitamin B6 It is essential for the synthesis of nucleic acid (DNA and RNA) and proteins. Antibodies (proteins which counter attacks the foreign organisms) and cytokines (small proteins important for cell signaling) are constructed from amino acids and require vitamin B6 for their metabolism. Vitamin D - Vitamin D stimulates the production of antimicrobial peptides which are essential for the first line defensive mechanism. Due to its anti-proliferative effect inhibitory effect on lymphocytes and cytokines), it also influences the immune response enhancing the immunity and by limiting the tissue damage.
Vitamin A Retinoic acid, a Metabolic of vitamin, enhances cytotoxicity and T cell proliferation; the latter probably mediated, at least in part, by enhancing IL-2 (cytokine) secretion and signaling in T cells.
Vitamin E vitamin is an immunoregulator. It enhances the immune response as it activates and stops the activity of free radicals.
Trace Elements Trace elements such as iron, selenium, copper, etc. are vital micronutrients that play various roles in physiological processes and are required in minute quantities for the proper functioning of the immune system. They function in immunomodulation and provide antioxidant activity.Certain trace elements inhibit the viral replication, thus possessing antiviral activity.
Iron It is involved in the regulation of cytokine production and mechanism of action, and in the activation of enzymes which are essential for phosphorylation of factors regulating cell proliferation. Moreover, iron is also necessary for the activity of enzymes like myeloperoxidase which are involved in killing process of bacteria by neutrophils.
Zinc It is necessary for coenzymes and essential for replication and transcription. It is also involved in the defense against oxidative stress by cytosolic defense action.
Selenium Selenium in coordination with vitamin E plays an important role in T cell-dependent antibody response. It is also one of the vital players in antioxidant function.
Effects of Malnutrition and Overnutrition on Immunity
Overnutrition is the state of nutrition when more than one constituent of a healthy diet is consumed in excessive amounts. Overnutrition could be general (any or all types of food) or specific related to a single nutrient (vitamin or mineral). Obesity is one the most common consequences of over nutrition.
Obesity Obesity is the most prevalent concern associated with over nutrition. Excessive consumption of macronutrients and micro nutrients adversely affects the immune system. Obesity has detrimental effects on immunity, changes in lymphoid tissue framework and integrity, transfer in leukocyte number and inflammatory phenotypes. Over nutrition also increases the chances of infection. Hormones like adiponectin and leptin, which have a key role in regulation of immune function, are released in obesity. Therefore, it is advisable to moderately consume the nutrients for maintaining optimum immunity.
Malnutrition It is a condition that occurs after consuming a diet that is either deficient in nutrients or excess in nutrients. Decreased nutrient absorption, decreased consumption of food, a spike in metabolic activity or requirements, excessive nutrition loss are some of the causes of malnutrition. Protein malnutrition in children causes thymus atrophy due to loss of small lymphocytes. It affects the development of peripheral lymphoid organs.
Keeping in mind the overall impact of nutrition on immunity, it is imperative to plan a diet that fulfills all the needs of the body. The key is to maintain a well balanced diet for overall well-being, and also to ward off unwanted diseases.
Immunity is the guardian of your body & nutrition helps to keep it stronger.