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All About Your Immune System

What it is, what it does, and why it’s important

Keeping Your Body Healthy Starts with a Healthy Immune System

The immune system plays an important role in helping your body stay healthy. But, what we often overlook is the importance of actually keeping our immune system healthy over the long term, rather than just when it’s stressed – and how to do it. For the immune system to do its job, it needs energy which comes from the foods we eat. A diet rich in nutrients from fruits, vegetables, and whole grains provides a better source of energy for the immune system than a diet lacking these foods. Maintaining a healthy lifestyle – including regular exercise, sleep, and stress management – can also help keep your immune system strong and healthy.

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What is the immune system?

The immune system is a complex system of organs, tissues, and cells that protects the body from external threats. This collection of cells, proteins, secretions, and chemical mediators works together to protect your body. It includes:

  • Physical barriers (skin, mucous, and the cell linings of the digestive tract, veins, and arteries)
  • Cells that send immune signals
  • Cells that defend the body 

Physical barriers keep invaders out, chemical signals attract specific and non-specific attack cells, and memory proteins stand ready to protect against future challenges. The immune system also includes chemicals that promote tissue repair and a return to health. When properly functioning, the immune system is constantly acting to shield your body and protect you when the body is compromised.

Immune System Facts

  1. Sunlight exposure helps increase vitamin D:  a nutrient associated with immune health.
  2. Managing stress in healthy ways can counteract the negative effects of on-going stress on your immune system.
  3. Inflammation can be a healthy part of the immune response, as your body “fights” to keep you healthy.
  4. Healthy sleep habits support a healthy immune response.
  5. Supporting gut health with a healthy diet, probiotics, and prebiotics – as supplements when appropriate – also plays a role in promoting immune health.

Protecting your Body

The body reacts to the environment through the immune system by launching a quick and calculated inflammatory response. This protective response is a healthy, necessary series of events that brings immune cells to the scene that are equipped to deal with the situation at hand. Your immune system has two types of responses: innate and adaptive.

Innate Immune Response 

The innate immune system is a non-specific response and is the first line of defense. Skin and mucous membranes form a physical barrier against environmental threats. Cytokines are messenger proteins of the innate immune response that serve to regulate immunity. Essentially, all immune cells produce cytokines. These messengers relay a variety of communications that direct the innate response, the adaptive response, and the production of blood cells.

Adaptive Immune Response

When the innate immune system is overwhelmed with its standard non-specific response, the adaptive immune response kicks in with a more targeted response. This specific response is composed of specialized white blood cells:

 B lymphocytes, also called B cells, produce specialized proteins called antibodies that activate your innate immune system

T cells are a part of the immune system that focuses on specific foreign particles

Immune System Terminology

Inflammation can be a healthy part of the immune response, as your body “fights” to keep you healthy    

Antibodies are specialized proteins for white blood cells to target

Cytokines are messenger proteins of the innate immune response that serve to regulate immunity

The Immune System’s Function

Your immune system has two types of responses: innate and adaptive. The innate immune system is a non-specific response – your first line of defense. It’s composed of standard white blood cells. But there are some challenges that the innate immune response cannot clear on its own. That’s where the adaptive immune system comes in – a specific response composed of specialized white blood cells, called B cells and T cells, that launch a targeted defense. B cells flag challenges so your innate immune system is activated, while T cells work double-time to eliminate the challenges. Your immune cells do all this work to protect you as a swift and calculated response

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Weak vs. Strong Immune System

When the immune system is weak, we are more vulnerable to a variety of symptoms that can keep us from feeling our best. When the immune system is strong, we are more likely to thrive. When a person has a ‘strong’ immune system, they are more likely to have the following qualities. On the opposite end of the spectrum, a person with a weak immune system would be more likely to have qualities seen on the ‘weak’ list.

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Supporting a Strong Immune System

In every system of the body, cells and tissues need nutrition for energy to support daily activities that keep the body functioning. The immune system is no different. Proper nutrition — including specific minerals, vitamins, and nutrients — is a key part of the equation for strengthening your immune system. The other part of that equation can be lifestyle choices that support a healthy immune system.

Nutrition for Immune Support


When your immune system is strong, you are more likely to thrive and feel healthier. Proper nutrition is one of the most valuable tools you have for supporting a healthy immune system. Supporting gut health with a healthy diet, probiotics and prebiotics – and supplements when appropriate – also plays a role in promoting immune health. While a diet generally rich in nutrients from fruits, vegetables, and whole grains is important, the following pages will outline specific foods, nutrients and herbs that can be particularly beneficial for the immune system. In most cases, supplementing your diet with these vitamins, minerals, and nutrients can also have a positive impact on your immune system’s strength and resilience.

Mushrooms such as shiitake, maitake, turkey tail, reishi, and cordyceps are associated with supporting immune system components. This includes white blood cells – including macrophages, natural killer cells and T cells – antibody production, and cytokine regulation2

Elderberry Research connects elderberry extracts with supporting the immune response3

Whole food fermentate derived from yeast is a novel compound associated with beneficial immune support. Metabolites in whole food fermentate support immune modulation.4,5

Echinacea has long been associated with beneficial immune effects. Research has linked echinacea with supporting dendritic cell maturation, macrophage activation, and natural killer cell activity.6,7

HMO's found most abundantly in human breastmilk, contain important human milk oligosaccharides like 2’-fucosyllactose (2’-FL) that act as prebiotics in the digestive system. To support adults, HMOs are available in a variety of other forms. Prebiotics feed the healthy bacteria of the microbiome, which is linked to whole-body health, especially the immune system. HMOs like 2’-FL support the integrity of the gut barrier in the lower gastrointestinal tract, which includes an immunological barrier important for gut immune health.8

Omega-3 fatty acids are polyunsaturated fatty acids (PUFAs) that play a number of roles in supporting whole-body health. In the immune system, omega-3s are important regulatory players and act as precursors for molecules involved in the resolution phase of inflammatory response.9

Vitamin A often associated with carrots and visual function, is also an important micronutrient when it comes to maintenance of important immune organs like the thymus. Found in a variety of foods like leafy green vegetables, orange and yellow vegetables, fruits, liver and fish oils, vitamin A has been shown to regulate the life cycle and function of innate immune cells10 discussed previously.

Vitamin C ascorbic acid, is a water-soluble vitamin found in many fruits and vegetables such as citrus, bell peppers, berries and kiwi. Research shows that vitamin C stimulates production of white blood cells, such as macrophages, T cells, and B cells. Vitamin C is also supportive of white blood cells through antioxidant activity.

Vitamin D a unique micronutrient, acting as a hormone rather than as a true vitamin. Ultraviolet B rays in sunlight trigger vitamin D production in the body, where it aids the immune system through B cell homeostasis, and support of regulatory T cells in immune tolerance.12,13 It supports both the innate and adaptive immune responses. Many people require vitamin D supplementation as there are limited whole food options and many have inadequate direct access to sunlight.

Zinc a trace mineral that is vital in maintaining the integrity of your skin, and it plays an important, multi-faceted role in immune health. Found in a variety of vegetables, fruits, whole grains and protein foods such as lean meats, poultry and eggs, zinc supports the integrity of physical immune barriers such as the skin, mucus membranes and epithelial lining.14 Zinc is also important for cellular immunity, T cell, and B cell support.15,16,17

Magnesium an essential nutrient that acts as a cofactor for hundreds of vital enzymatic reactions in the body. Its role in immune health may include supporting healthy sleep and helping to support healthy inflammatory response.18 Emerging research indicates magnesium may also play a role in the human immune system response such as through magnesium transporters. A number of magnesium transporters have been identified in immune cells.19

Prebiotics and Probiotics Prebiotics are substances that support the body by stimulating the growth of beneficial bacteria and increasing the functionality of the gut microbiome. They help provide energy to intestinal cells and improve the function of the intestinal barrier.20 

Probiotics also provide important benefits to the body.18 These live microorganisms can influence immune signaling and contribute to the production of antibodies which are critical components of a healthy immune system.18,21 The gut microbiota also affect the immune system beyond the gut, including in the liver, brain, and lung.19

Blog - [Checklist] 6 Foods That Support Your Immune System

Additional Resources

Clinical & Research-Based Recommendations For Supporting Immune System Health

Facing Stress By Supporting Immune System Health

Immune System Supplement Research: Congaplex®, Immuplex®, And Epimune Complex

WholisticMatters Immune Support & Stress Management Education Hub

How to Strengthen Your Immune System

In addition to food, lifestyle habits, nutrients, and supplements can affect the strength of your immune system. Healthy lifestyle habits are key to healthier immune systems.

Regular Exercise

is important for whole body health, and that includes a healthy immune response. Physical activity has been shown to support circulation of immune cells throughout the body, regulation of inflammatory response, and optimizing specific antibody responses22,23,24 when needed. Exercise also has a positive impact on stress management and gut health, which in turn supports a functioning immune response in the gastrointestinal tract.

Healthy Sleep Habits

are supportive of whole-body health, the immune system included. Healthy sleep supports regulation of pro-inflammatory and anti-inflammatory response substances – a balance between the two is important for a healthy, functioning immune system. Of note, magnesium is one of many nutrients that is important for sleep. Research indicates that magnesium supports quality sleep by helping you fall — and stay — asleep.26,27,28 It also helps regulate melatonin production.


whether physical or psychological, triggers a physiological response that can negatively impact your immune system if not addressed and managed. The stress response indicates potential danger to the body, thereby activating the innate immune system with proinflammatory hormones. Cortisol, an anti-inflammatory stress hormone, is also produced to combat its proinflammatory counterparts.29 How stress affects immune health depends on each individual as well as the duration and intensity of the stress response. Learning to manage stress in a healthy way can support your immune system and its ability to provide whole-body protection.30,31

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Immune System Supplements

No matter the time of year, having a protocol to support your immune system support is always a good idea. Standard Process and MediHerb have several supplements that support immune health,* making immune system support supplements a convenient way to protect yourself.

Immune System Health Pack

Convenient everyday immune system support packs that contain Immuplex®, Cataplex® F, Cataplex® C and Calcium Lactate

Immune System Health Pack – Vegetarian

Convenient, everyday vegetarian immune system support packs that contain Epimune Complex, Cataplex® D, and Echinacea-C™

Epimune Complex

Helps balance a healthy immune system response function and delivers an excellent source of vitamin C and zinc*


Daily support for healthy immune system response function and provides ingredients with antioxidant activity


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