INL Articles - The Immune System and Nutrition
An introduction to the different components of the immune system and how nutrition can help
The immune system and the “strengthening” of its various components have never been more scrutinized in 2020. With autoimmunity steadily on the rise and most common treatments palliative or suppressive in nature, our understanding of the immune system and where and how to best to intervene needs to evolve.
Before looking further into this and a new level of semantics we can use to describe how natural medicine can be best administered let’s revisit some of the key areas of the immune system and how they work together to protect us from ever-changing environment.
The interaction between Innate and Adaptive Immunity
The easiest way to frame these two important components of the immune system is via general and specific immunity or first and second line of defence.
Innate immunity is akin to “first responders” made to act quickly but more generally either through physical barriers, epithelial defensins, phagocytic activity and the recognition of foreign invaders ready for the more specific adaptive immune system to act with targeted antibodies.
The innate immune system predominantly refers to neutrophils, monocytes, dendritic cells and macrophages. The innate immune system does not mount a response against a particular antigen but does activate the thymic lymphocytes or T cells and also the B cells found in the bone marrow. Both are key parts of the adaptive immune system, activated by antigen presentation mediated especially via dendritic cells and neutrophils.
Neutrophils also create some rapid-acting peptides called cathelicidins and defensins that express anti-viral, anti-bacterial and anti-microbial properties. (1) Other key proteins from the innate immune system are more well-known such as calprotectin and lactoferrin. (2)
High neutrophils in a blood count can indicate active innate immunity such as acute viral or bacterial infection or may result from chronic inflammation. Note that acute physical stress can also activate the neutrophil count. (3)
An indication of stress can be gained by the ratio of Neutrophils to Lymphocytes. It’s called the Neutrophil-Lymphocyte Ratio (NLR), and it increases when stressed. (4) The NLR is simply the number of neutrophils divided by the number of lymphocytes.
Under physiologic stress, the number of neutrophils increases, while the number of lymphocytes decreases. The needs to be < 5, optimally 2-3 for these lymphocytes to be at correct levels. Less lymphocytes means less of the thymic T cells and NK cells are to be found, that is the Th1 system is weak. Neutrophils may be induced by excess exercise, physical stress (e.g., postsurgical, febrile seizures), emotional stress (e.g., panic attacks), smoking and the chronic inflammatory pain conditions such as RA and IBD.
Lactoferrin and Vitamin D3 for the regulation of the innate immune system
Lactoferrin as a supplement is potent at upregulating the innate immunity as is vitamin D3. Lactoferrin particularly helps activity of dendritic cells, often slow in elderly patients, which can affect their dendritic cell activation of Th1 and B Cells into antibody production. Lactoferrin is also known to exert changes on leukocytes of the innate immune system, through increasing natural killer (NK) cell activity, promoting function of neutrophils by enhancing phagocytic activity and modifying production of reactive oxygen species, and activating macrophages through increasing NO production all which together limits intracellular pathogen proliferation. (5)
As shown above, the innate immune response also utilizes Toll-like receptors (TLRs), a subgroup of pathogen recognition receptors (PRRs) that are present in all the innate immune cells i.e. macrophages, neutrophils, eosinophils, basophils, monocytes, dendritic and epithelial cells. The recognition of invading microbes by TLRs on Dendritic Cells for example induces proinflammatory cytokine production and enhanced antigen presentation to naive T cells, and finally activates antigen-specific adaptive immune responses. The sequential activation of innate and subsequent adaptive immunity are crucial steps to eradicate invading pathogens.
TLRs recognize molecules related to the pathogen; for example, the lipopolysaccharides of bacteria or viral nucleic acids and proteins. Such activated TLRs, such as TLR4 release cytokines which induce reactive oxygen species (ROS) and antimicrobial peptides (AMPs) from the macrophages, increasing their antibacterial activity, so also enhance the innate responses. TLR4 is upregulated in these innate system activities with vitamin D3. (6)
Vitamin C plays a key role in the innate system by stimulating neutrophil migration
It’s worthwhile adding here that vitamin C is concentrated by the innate macrophages and neutrophils. Vitamin C stimulates neutrophil migration to the site of infection, enhances macrophage and neutrophil phagocytosis and oxidant generation, and thus microbial killing. At the same time, Vitamin C protects host tissue from excessive damage by enhancing neutrophil apoptosis and clearance by macrophages and decreasing neutrophil necrosis and NETosis (which is DNA ejection from neutrophils, leading to WBC apoptosis, a catastrophic means of inviting more cytokine and thrombotic activity). (7)
For this reason vitamin C demands rise rapidly during the early stage of innate responses e.g. during febrile infections, so that much higher levels, 5,000-10,000mg, can be absorbed during infections, without causing the usual diarrhoea. In this sense vitamin C is effective support for the innate immunity, but mostly needed when in the early stage of infection, it barely helps to prevent infections, unlike vitamin D3. Vitamin C has little influence on the adaptive antibody system.
Vitamin A & Zinc play an important role in antibody production
Once the antigen presenting cells (mainly dendritic cells and monocytes) bring antigens to the lymphocytes, the adaptive system can go into production of antibodies via T-lymphocytes (cell-mediated immunity) and B-lymphocytes (via humoral immunity) to mount the more targeted response.
For this, Vitamin A and zinc are the more effective and necessary nutrients for antibody production. While vitamin A also supports the innate system in producing healthy epithelial barriers, and a crucial role in the mucus layer of both the respiratory tract and the intestine, it is also crucial for Thymic CD8+ and assists the formation of antibodies following the viral infections and viral related vaccines such as MMR. Vitamin A has been shown to reduce measles related morbidity and mortality. (8)
So much more on this subject to come but for now we hope you enjoyed part one of this introduction to the different elements of the immune system. In the next INL education newsletter we look more towards cytokines and systemic immunity.
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Vitamin A is an important nutrient for vision, immune system function, bone and cartilage development, and the maintenance and repair of epithelial tissue. This formulation combines two forms of vitamin A—palmitate and betacarotene—that have been micellized into extremely small droplets that are easily absorbed into the bloodstream. Potassium sorbate provides a safe, well-tolerated, and hypoallergenic stabilizing agent for the liquid Micellized Vitamin A preparation. Each drop supplies 1,507 mcg RAE of vitamin A.
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