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Our immune system is designed to keep us from getting sick and is critical for survival.

The immune system is a network of organs, special tissues, cells, and proteins that communicate and work together to provide an immune response to protect our bodies.

It is designed to keep out unhealthy invaders like pathogenic bacteria, viruses, fungi, and worms as well as environmental threats like chemical pollution and environmental toxins.

A healthy immune system can differentiate between foreign invaders and our own tissue.

Gut health is foundational to a healthy immune system. Supporting the gut microbiome and restoring the gut lining is one of the first things I address when supporting immune health.

A healthy immune system reacts with an appropriate response — identifying and addressing true foreign threats, and then calming down when the threat no longer exists.

An underactive immune system (immunodeficiency) may result in recurring infections. As we age, our immune systems weaken and it’s easier for us to get infectious diseases.

A hyperactive immune system overreacts to foreign materials or organisms, (allergens or antigens); it may result in the development of allergies, asthma or eczema.

A hyperactive immune system may also mistakenly identify tissue in one’s own body as foreign and attack it. This can lead to development of an autoimmune disease.

The Immune System – An Oversimplified View

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The Skin

Physical barriers like the skin are the first line of defense, keeping unwanted organisms or toxins from entering the body. Breaks in this barrier (cuts, burns) make us more vulnerable.

Foreign material can bypass the first line of defense by entering other ways, like through nail beds, vaginal and urinary tract, nose, eyes and mouth. Every time we eat food, we are exposed to toxins, foreign antigens and microbes.

The Gut

The GI tract is an absolutely essential part of our immune system.

Stomach acid creates a hostile environment for pathogens — they usually cannot survive in such an acidic environment. Continual use of antacids interferes with this protection. There is a decrease in the acidity of the stomach with aging.

A large proportion of the immune cells are located in the gut (referred to as gut-associated lymphoid tissue or GALT); these immune cells serve to attack and remove many foreign invaders before they penetrate further into our bodies.

Protease enzymes break down many pathogens in the gut.

Mucus in the GI tract lining is like a second skin. It helps repel foreign invaders and helps keep them from getting across the gut barrier and into the blood, lymph, and ultimately, interior cells.

Imbalance and overgrowth of intestinal flora and toxins they produce (e.g., yeast) can inflame and compromise the mucosal lining; if pathogenic organisms get past this mucosal barrier they can establish themselves on the deeper surface lining of the GI tract. Once established a foothold, gut junctions can become less tight/the gut abnormally permeable. Foreign invaders (pathogenic microbes and toxins) and larger than normal macromolecules can leak through, hence the name, “leaky gut syndrome.” These out-of-place substances can initiate an immune response having an adverse effect on overall health.

Food may inflame the gut if you have intolerance or sensitivity. Chronic inflammation may further compromise the mucosal barrier and contribute to “leaky gut.”

There are millions of neurons in the gut (enteric nervous system) which produce neurohormones that communicate with the brain. Stress affects GI tract health and consequently your immune function.

Respiratory System

After the GI tract, the respiratory tract has the body’s second-largest mucosal surface area.

The lining of the respiratory tract — nasopharynx, sinuses, lungs and bronchi, is a barrier to germs, viruses and other harmful invaders. Many viruses use the host’s mucosal surfaces as their initial portal of infection.

Coughing and sneezing are mechanisms with which we eliminate foreign material.

The Innate Immune System

If pathogens make it through our first lines of defense and get into cells, the innate immune system, a non-specific generic immune response “kicks in.” The injured cells produce chemicals (cytokines) some of which produce an inflammatory response and others which “recruit” white blood cells to the injured site.

Enzymes which break down proteins (proteases) work with antibodies to attack the foreign cells. Many types of white blood cells go into action to eliminate the pathogens, often by engulfing them and killing them. There are also natural killer cells that destroy our own cells that have been damaged by the pathogens.

The innate immune system does not retain a memory of its experience (it does not confer immunity). This system does not result in better protection the next time the same pathogen invades the body.

The Adaptive Immune System

If the pathogens are not thwarted by the innate immune system, then the adaptive immune system goes into action. It is targeted toward that particular pathogen and even retains a “memory” of the pathogen, ready and stronger for it in case it comes back. (Vaccines work with the adaptive immune system.)

The adaptive immune system works through antibody formation.

What Can You Do to Support Your Immune System?

  • Eat a healthy diet — high in fruits, vegetables, whole grains, foods high in fiber and those with probiotics. Fruits and vegetables are rich in antioxidants like flavonoids which are concentrated in their pigments. Think “rainbow” colors. Look for purples, blues, reds, oranges and yellows. Foods that are eaten raw or lightly cooked will retain more of the antioxidants. These foods are also rich in enzymes. Incorporate recipes with cooked mushrooms into your diet. Edible mushrooms have potent compounds like beta glucans, glycoproteins and natural antibiotics that provide immune support.
  • Follow practices that reduce the risk of exposure to pathogens and toxins – cook meats and poultry thorougly, don’t eat raw dairy products like raw cheeses, wash fresh fruits and vegetables thoroughly, and use a separate cutting board for cutting up raw chicken, meat or fish.
  • Stay hydrated – drink lots of water throughout the day.
  • Exercise – maintain a regular exercise regimen and maintain a healthy weight.
  • Get adequate sleep – preferably 8-9 hours a night. Sleep is a restorative process.
  • Limit psychological and emotional stress – easier said than done but it’s widely accepted that there’s a close relationship between body and mind. It’s thought that stress may affect the immune system by disrupting the chemical messages sent between the nervous, endocrine and immune systems. Stress hormones (cortisol and other glucocorticoids secreted by the adrenal glands) are released when under stress. These stress hormones have numerous effects on the immune system.
  • Limit environmental stressors – don’t smoke, drink in moderation if you drink alcohol.
  • Avoid infection as much as possible – wash hands regularly especially if you are interacting with people who are sick.
  • Take dietary supplements that maintain or restore the gut lining, support a healthy microbial ecosystem and have anti-microbial properties.

Nutrition Supplements and Immune Health

SHOP IMMUNE HEALTH

Probiotics and Gut Mucosa Building Blocks – a good probiotic formula helps suppress unhealthy bacteria, promote growth of healthy commensal bacteria. Restoring the balance of a healthy intestinal microflora supports the maintenance of a healthy gut lining.  When the gut lining is “leaky,” the body can even perceive certain foods as foreign, triggering an immune response.

Read more: Probiotics and Immune Health


N-acetylcysteine – activates immune cells as well as regulates the immune system so that it’s less likely to contribute to an auto-immune process. NAC is a procursor to glutathione, the body’s master antioxidant.


Botanicals and Mushrooms –  boswellia works by modulating inflammation of the gut and respiratory linings.

Curcumin (key component of turmeric) is an immunomodulator and anti-inflammatory compound.

Medicinal mushrooms or medicinal yeast primes immune system to be ready to respond (but not overreact) when infectious agents come along.

Other botanicals like elderberry, echinacea, quercetin, andrographis and astragalus directly fight pathogens or have compounds that can modulate the immune system.

Read more: Mushrooms Are Good for  Immune Health

Read more: Boswellia and Immune and Respiratory Health


Therapeutic Enzymes – certain proteolytic enzymes (proteases) are capable of digesting the protein coating of pathogens (viruses, yeast, fungi, bacteria, parasites) in the blood. This makes the organism more vulnerable and exposes them to degradation. The proteases also promote cellular repair and recovery.

Read more: Enzymes and Immune Health


L-lysine – an essential amino acid that exhibits antiviral properties and may reduce severity or frequency of outbreaks of cold sores and Herpes simplex.


Vitamins —Vitamin D3 can modulate the innate and adaptive immune responses. Having adequate levels of Vitamin D imay lessen the impact of infection and autoimmunity on health; low levels of vitamin D may be associated with increased risk for respiratory illness. Aging and sunscreen reduce the body’s ability of the body to produce Vitamin D. Have your doctor check your vitamin D levels.

Other vitamins that play important roles in a healthy immune system include Vitamin C and Vitamin A.

Immune Health Definitions

Lymphoid Organs – organs that store leukocytes, a type of white blood cell (thymus, spleen, bone marrow, and lymph nodes).

Lymphatic System – like a secondary circulatory system. Lymphatic vessels transport lymph fluid back from the tissues to the circulatory system. Part of the immune system, it works in concert with white blood cells in lymph nodes to protect the body from cancer cells, fungi, viruses or bacteria.

Leukocytes – white blood cells. They are involved in phagocytosis which engulfs and kills invading organisms and in releasing chemical mediators and antibodies.

Antibodies – specific proteins that lock onto specific antigens and destroy or neutralize them.

Antigens – foreign substances that invade the body.

Innate Immunity – natural non-specific immunity with which people are born. It includes the physical barriers like the skin and mucous membranes.

Adaptive Immunity – an active specific immunity. This changes throughout our lives based on exposure to specific germs or vaccinations.