Our body has an incredibly strong first barrier against pathogens, bacteria and viruses, this is what we call the immune system. The human immune system is comprised of numerous forms of white blood cells used to fight foreign bodies.
The Human Immune System
The human immune system is made up of white blood cells that are used in the innate or adaptive immune response. The adaptive immune system is used in secondary or slow response immune health.
The innate or non-specific immune system is made up of cells called natural killer cells (NKs), macrophages. phagocytes, neutrophils, basophils, eosinophils and mast cells. These typically respond within 0-96 hours of pathogen detection. Other portions of the innate immune system include the skin, hair (eyelashes), mucous, saliva, sweat, gastric acid. One of the main actions of the phagocyte is a process called phagocytosis. If phagocyte sees a ‘foreign cell’ or pathogen it will begin the process of phagocytosis whereby it consumes and destroys the foreign cell within its own cell. Whereas macrophages circulate the body and release cytokines which are warning signals to other cells to flock to that area and attach the foreign cells.
The adaptive or specific immune response is made up of T and B lymphocytes. This reacts over 96hours or much faster upon second exposure of the same pathogen. B cells are made in the bone marrow. On the surface of these B-cells there are membrane-bound antibodies. Once the antibody fits an antigen like a lock in a key, the B cell rapidly generates and specialises into a memory or effector cell. Effector or plasma cells are then able to produce and release antibodies that are not membrane-bound. Therefore, they are able to travel and circulate. The T-cells are made in the thymus.T cells, unlike B cells are unable to detect pathogens unless they are attached to a MHC complex which presents the pathogen to the T cell. Like the B cells, T cells differentiate and specialise into helper, cytotoxic or regulatory T cells. These are known as memory cells. Which means that they remember specific antigens of pathogens and have a ‘plan of action once the body is exposed to the pathogen again.
Nutrition for Immune Health
Vitamin A carries a European food safety authority (EFSA) approved health claim that it supports the normal function of the immune system. Vitamin A has vital roles in the immune system as well as reducing inflammation.One of the roles of Vitamin A is to encourage the production of mucosa which is a primary defence mechanism against pathogens. Animal studies show that vitamin A deficiency can lead to decreased efficacy of the T cell-mediated and antibody-dependent immune responses.
Numerous B-Vitamins carry the EFSA approved health claim for the maintenance of the immune system including Vitamin B6, B12 and Folate (B9). Studies have shown that Vitamin B9 deficiency can lead to a reduction in CD8+ T cells and natural killer cells and this can lead to an increased chance of infection.
Much like the vitamins mentioned above. Vitamin D also carries an approved health claim for improved immune function. Vitamin D can be metabolised to 1,25-dihydroxyvitamin D [1,25(OH)2D]. A deficiency of Vitamin D has lead to a deficiency of this metabolite which has been linked to increased inflammation in the body.
Zinc is needed for white cell maturation, differentiation and correct immune cell functioning. According to EFSA, zinc contributes to the normal function of the immune system. One study even called it the ‘gatekeeper to the immune system’. Whereas another study concluded the following ‘In humans, clinical manifestations of zinc deficiency include weight loss, growth retardation, atrophy, and immune dysfunction, as well as increased oxidative stress and a boosted inflammatory immune response’.
Selenium is a trace element it carries the approved heath of helping to maintain the human immune system. Selenium is used by the body to create glutathione peroxidases (GPx). There a number of GPx labelled 1-8. GPx 1 and 4 are the most prevalent selenium-containing proteins in several immune cells and tissues. Human studies have shown that selenium supplementation may enhance humoral and cell-mediated immunity.
Healthy Lifestyle Techniques to Reduce Immune Risk
● Try to catch coughs and sneezes in a tissue or the crook of your elbow.
● If you sneeze or cough into a tissue, dispose of the tissue straight away.
● Wash your hands regularly.
● Wash your hands for at least 20 seconds.
● Wash your hands after touching common areas touched by others, for example, handrails, door handles and surfaces.
● Carry hand-sanitiser with you whilst in public spaces.
● Avoid physical touching if possible, i.e shaking hands.
● Try to stay away from those vulnerable to an immune threat such as the elderly, pregnant, young children or the immune-suppressed.
To help to maintain a healthy immune system I would recommend the following supplements:
● Vitamin A
● Vitamin D
● B Vitamin Complex
● Vitamin C
● Zinc and Selenium
● Greens - spirulina and chlorella
WRITTEN BY HARRIET HUNTER, ANUTR. NUTRITIONIST
● https://www.healio.com/hematology-oncology/learn-immuno-oncology/the-immune-syste m/the-innate-vs-adaptive-immune-response
● https://www.khanacademy.org/test-prep/mcat/organ-systems/the-immune-system/a/innat e-immunity
● https://oncologypro.esmo.org/education-library/essentials-for-clinicians/lymphomas/chapt er-1-the-immune-system