The body’s immune system is in charge of battling foreign substances such as viruses, parasites, and bacteria. Without a healthy immune system a person is susceptible to colds, infections, slow healing wounds, stress, fatigue, diseases, and more.
It’s possible to get all of the vitamins, minerals, and other nutrients that support the immune system from foods. But realistically, that’s not always easily accomplished. Depending on where you live, some or many of the foods that are rich in some particular nutrients may not be readily available. Additionally, if you want to get a good share of all of the nutrients that are beneficial to the immune system, you’d have to eat a lot of food. That’s why this article includes food sources of these nutrient and good supplements for the same nutrients.
- All About the Immune System
- Nutrients That Support a Healthy Immune System
- Protein and the Immune System
- Omega-3 Fatty Acids and the Immune System
- Fiber and the Immune System
- Vitamins and Minerals and the Immune System
- Spices and the Immune System
All About the Immune System
Your immune system is responsible for fighting foreign substances, both external and internal. Whether germs and foreign invaders are on your skin, in your body tissues or within your bodily fluids, it’s the immune system’s job to fight back. The immune system fights viruses and pathogenic (disease-causing) bacteria, and even kills cells in the body should they become cancerous.
It’s hard to overstate the importance of a healthy immune system. After all, this system is essential to a person’s — and humanity’s — survival. Without an immune system — or even with an immune system in poor health — our bodies would be open and subject to attack from parasites, viruses, bacteria, and more. A weakened or under-active immune system exposes your body to increased susceptibility to disease and infections.
A body’s cells each have a unique surface molecule called an MHC that acts as a self cell marker — it signals to the immune system that it is a “friend” to be tolerated and ignored. An antigen, or foreign molecule, doesn’t have such an MHC marker, causing the immune system to recognize it as non-self that should be treated as a “foe.”
When the immune system is out of balance it fails to protect the body — and it can even attack it. The unhealthy immune system’s ability to recognize MHC markers becomes weakened, resulting in it occasionally mistaking self cells for non-self cells. When the immune system then attacks cells that are normal and natural to the human body, the results can be autoimmune diseases such as rheumatoid arthritis or lupus.
Organs and Tissues of the Immune System
At the micro level the immune system is comprised of specialized proteins and several types of white blood cells (WBCs) that travel through the body inside lymph vessels. At a more macro level are a number of organs and tissues
Skin and mucous membranes in the nose and throat are organs that function as physical barriers and serve as the first line of defense to prevent germs entering from outside your body.
Several other immune system organs are considered lymphoid organs. Bone marrow and the thymus create special immune system cells called lymphocytes. The spleen, lymph nodes, tonsils, and tissue in mucous membrane layers in some organs (such as the bowel) are where the actual work of fighting off germs and foreign substances takes place. How these organs react to foreign challenges to the body is referred to as the body’s immune response.
The Immune System’s Immune Response
The organs and tissues of the immune system respond, or work, in two different ways to make up two lines of defense. These responses work closely together to handle different tasks.
- Innate, or non-specific, immune response
- Adaptive, or specific, immune response
The two responses are also sometimes thought of as subsystems that collectively make up the immune system, so you might see each referred to as a system itself, as in the innate immune system and the adaptive immune system.
|Line of Defense||Timeline||Cells||Antigen Dependency||Examples|
|First||Immediate response (0-96 hours)||Natural killer cells, macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils||Independent||Skin, hair, cough, mucous membranes, phagocytes, granulocytes|
|Second||Long term (>96 hours)||T and B lymphocytes||Dependent||Puss, swelling, redness, pain, T and B lymphocyte response|
The Immune System’s Innate (Non-Specific) Immune Response
The innate response, or non-specific response, is the immune system’s first line of defense against pathogens — virus, bacteria, or other microorganism that cause disease.
The primary purpose of the innate immune response is to quickly stop the movement and spread of pathogens throughout the body. Within minutes or hours of the appearance of an antigen (a foreign substance that causes an immune response) the innate response is to attack the foreign entity.
The innate response is said to be non-specific because its actions are the same regardless of the type of antigen it’s fighting. Its fast action is good in that it can bring about an almost immediate end to an immune system threat. It’s non-specific nature, though, has a downside in that this response has limited power in stopping foreign substances from spreading — its singular approach doesn’t work efficiently against every type of antigen.
The skin and mucous membranes of the nose and throat are a part of the innate response — they form a physical barrier that blocks entry of many pathogens. Internally phagocytes — a type of white blood cell capable of engulfing foreign bodies — prevent antigens that have entered the body from gaining a foothold.
The Immune System’s Adaptive (Specific) Immune Response
The innate, or non-specific, immune response is the immune system’s first line of defense against pathogens. The innate response is a bit crude in that it has a sort of “one size fits” all approach to fighting invaders. It’s a very fast-acting system that’s pretty effective, but it’s far from perfect.
That’s where the second line of defense comes in — the adaptive, or specific, immune response. When the innate response system isn’t able to destroy an invader, the adaptive response system takes over. The adaptive immune response isn’t general — it’s specific to the antigen it encounters.
The main weapon in the adaptive response arsenal is clonal expansion of lymphocytes. A lymphocyte is a particular type of white blood cell (WBC) that is produced in bone marrow and is found in lymph tissue and blood. The two primary types of lymphocytes are B-lymphocytes, which make antibodies, and T-lymphocytes, which kill tumor cells and participate in controlling an immune response. Note that B-lymphocytes and T-lymphocytes are sometimes referred to as simply B-cells and T-cells.
When the adaptive response system recognizes an antigen, clonal expansion begins. This is the proliferation of B-lymphocytes and T-lymphocytes by cloning identical cells. The system begins with as little as a few B-lymphocytes and T-lymphocytes that are specifically designed to attack one particular invader type, and clones them to produce millions of identical B-lymphocytes and T-lymphocytes.
The first line of immune defense — the innate response — is close to immediate. This second line of immune defense — the adaptive response — isn’t. It’s a more complex system that has to work to identify the particular type of invader and then act to massively clone lymphocytes to fight the invader. The complexity of the adaptive response really pays off in the future, as part of the response is T-lymphocyte cell “memory” that makes recognition of a particular pathogen much faster should the same pathogen present itself in the future.
Nutrients That Support a Healthy Immune System
A healthy immune system is imperative to a healthy body. Fortunately, there are a few things anyone can easily do, every day, to support good immune health. These steps include:
- Managing stress
- Practicing good hygiene
- Getting a proper amount of sleep
- Participating in regular exercise
- Consuming adequate levels of key nutrients
The last point may be the most important one. The immune system requires a regular (daily) supply of many kinds of nutrients in order to run smoothly. Whether these nutrients come from diet, nutritional supplements, or, most likely, both isn’t important — as long as the the nutrients are consumed daily.
Protein and the Immune System
Protein is well-known for its crucial role in building and repairing muscle tissue. But protein has important roles in other physiological processes, including keeping hormones in balance, providing structure for skin, nails, hair, and organs, and supporting immune system health.
The digestive system breaks down protein into amino acids that are important in the activation and proliferation of B-lymphocytes and T-lymphocytes, as well as in the production of antibodies. Studies have found that a diet low in protein impairs the immune system, increasing the possibility of weakness, fatigue, infections, and poor immune response.
There are plenty of foods rich in protein. So many, in fact, that aside from a desire to increase body mass (bodybuilders), there’s little reason to purchase protein or amino acid supplements. And while it’s meat, poultry, and seafood that are best known as protein-rich foods, as the below list shows vegetarians and vegans should be able to get all the protein they need from a meatless diet.
- Lean meats: beef, pork, lamb
- Poultry: chicken, turkey, duck
- Dairy: milk, cheese, yogurt
- Soybeans (tofu, tempeh, and edamame)
- Nuts and seeds
- Beans (white, black, navy, pinto, kidney)
- Wild rice
Omega-3 Fatty Acids and the Immune System
Omega-3 fatty acids are a type of polyunsaturated fatty acid (PUFA) associated with several health benefits. Omega-3 can minimize the possibility of developing heart disease, improves skin elasticity and eye health, and limits age-related mental decline. This fatty acid has anti-inflammatory properties that help support the immune system in an interesting way.
When tissues are injured by heat, toxins, trauma, bacteria, or any other cause, the immune system may act with an inflammatory response. Intermittent rounds of inflammation directed at invading pathogens serve to protect the body. However, if inflammation persists for too long — as can occasionally happen — it becomes harmful rather than helpful. As an anti-inflammatory omega-3 supports the immune system by stopping the immune system from doing its work — but only when the immune system is going overboard in its production of inflammation.
While it has been understood for quite a while that omega-3 fatty acids have anti-inflammatory properties, it has only fairly recently been discovered that omega-3 further supports the immune system in another way. Omega-3 positively influences the functioning of B-cells (B-lymphocytes) — the lymphocytes that make antibodies.
Diets that are low in omega-3 fatty acids are often associated with chronic inflammatory conditions and autoimmune diseases such as rheumatoid arthritis, lupus, and Graves’ disease. Several foods contain omega-3 fatty acids, but certain fish are easily the most omega-3 rich foods you can eat.
- Cold-water fish (tuna, salmon, mackerel, and sardines)
- Flax seeds
- Pumpkin seeds
- leafy green vegetables
Cold-water fish are by far the primary source of omega-3 fatty acids. Seafood is also expensive, and perhaps not a food a person wants to eat every day of the week as well. That makes omega-3 a good candidate for a nutritional supplement.
In the past, fish oil has been the omega-3 supplement of choice. It still is considered a good source, but now krill oil, which is processed from the small shrimp-like crustaceans called krill, is thought to be superior. The omega-3s from krill have better bioavailability (have a greater ability to be absorbed and used by the body), and krill oil contains astaxanthin — a very powerful antioxidant not found in fish oil.
Fiber and the Immune System
Bacteria has a bad rap as being, well, bad. But human health relies on trillions of goodgut microbiota.
While the gut microbiota is best known for its important role in maintaining healthy digestive function, there is a strong connection between these friendly bacteria and the immune system. Evidence shows that gut bacteria assists the immune system in a number of ways.
- Degrades toxic compounds
- Defends against harmful microorganisms
- Helps teach the immune system to tell friends from foes
- Helps in the development of T-cells (T-lymphocytes)
Dietary fiber is directly connected to a healthy gut microbiota. Fiber is an important “food” of the friendly bacteria that make up the gut microbiota — bacteria are living organisms, and like any other living organisms, they need “fuel” to survive and carry out their functions.
Fiber isn’t digestible by your digestion system — only the gut bacteria can metabolize and process it. Your body’s friendly bacteria desperately need plenty of fiber, and even a short-term lack of fiber in the diet may significantly alter the effectiveness of your gut microbiome. Because processed foods have become such a prevalent part of the American diet, the average American consumes well under 50 percent of the recommended dietary fiber level. So … make sure you’re eating plenty of the plant-based foods from the following list. In doing so, you won’t need to buy any kind of fiber supplements.
- Whole grains
- Brown rice
- Bran cereal
Vitamins and Minerals and the Immune System
While all vitamins and minerals contribute to supporting the immune system, significant research shows that several play an outsized role: vitamins A, C, E, the B-complex vitamins, and the minerals copper, iron, and zinc.
Vitamin A and the Immune System
Vitamin A is well-known for its positive impact in tissue growth and eye health — but is also plays essential roles in supporting the immune system. Vitamin A is often called the anti-infection vitamin because it assists the body in its fight against bacterial, viral, and parasitic infections.
Recent studies demonstrate that vitamin A is a key part of a tolerant immune system — something critical to good health. Immune tolerance, which is vital for maintaining normal health, comes in two flavors:
- Central tolerance is the primary way in which the immune system learns to determine self cells (“friend” cells)] from non-self cells (“foe” cells).
- Peripheral tolerance is important to keeping the immune system from over-reacting to environmental entities such as allergens and gut bacteria.
Vitamin A deficiency can impair T-cell activity and impair the function of antibodies. You can easily avoid such a deficiency by eating items from this list of foods rich in vitamin A.
- Beef liver
- Sweet potato
B-Complex Vitamins and the Immune System
The eight B vitamins that make up the B group, or B complex, are referred to as the building blocks of the body because collectively they help to keep up energy levels, help produce red blood cells, and help support immune system health. Each of the B vitamins has an important role in maintaining a healthy immune system.
- Vitamin B1 (thiamine): important in normal antibody response
- Vitamin B2 (riboflavin): important in normal antibody response and acts as an anti-inflammatory and antioxidant
- Vitamin B3 (niacin): reduces inflammation and helps the innate (non-specific) immune system conquer antibiotic-resistant staph bacteria (also called superbugs)
- Vitamin B5 (pantothenic acid): decreases stress and helps in the production of antibodies
- Vitamin B6 (pyridoxine): plays a large role in the production of T-cells (T-lymphocytes) and interleukin-2 (a protein that directs white blood cell activity)
- Vitamin B7 (biotin): contributes to white blood cell development
- Vitamin B9 (folate or folic acid): contributes to red blood cell development and supports cell growth and function
- Vitamin B12 (cobalamin): improves nerve cell function and reduces the risk of developing anemia
As an aside, if you’ve ever wondered why there are no vitamins B4, B8, B10 and B11 in a B-complex supplement, it’s because while such substances do exist, they no longer meet the definition of a vitamin. That is, they aren’t essential for normal human growth or functioning.
The B-complex vitamins can be obtained from any diet that includes some of the following foods.
- Lean meats: beef, pork, lamb
- Poultry: chicken, turkey, duck
- Fish: Sardines, salmon, tuna, cod
- White beans
- Green leafy vegetables
All of the B vitamins are essential but unlike several other vitamins, the human body can’t produce or store them. That’s why B-complex supplements are so popular — it’s nice to pop one every day to ensure you’re getting adequate levels of all eight vitamins, daily.
Vitamin C and the Immune System
Vitamin C is helpful in supporting wound healing and healthy tissue growth. From an immune system standpoint, vitamin C is a powerful antioxidant that supports the healing of areas of inflammation. Vitamin C is also important for its ability to stimulate the production of white blood cells and its role in helping phagocytic cells function properly.
Earlier we discussed lymphocytes. Recall that there are different types of T-lymphocytes (T-cells) that are each designed to attack a particular pathogen. Phagocytes are another type of immune system cell. Unlike T-cells, phagocytes can destroy any type of pathogen they encounter.
It’s suggested that iron be taken along with vitamin C to help in its absorption (iron is another nutrient that contributes to immune health, and is covered just ahead a bit). If you enjoy citrus fruit or green vegetables, your diet most likely satisfies your vitamin C requirements.
- Citrus fruit: oranges, grapefruit, lemons
- Beet greens
- Collard greens
- Bok choy
Vitamin E and the Immune System
Vitamin E is a powerful antioxidant that supports a healthy inflammatory response — the inflammation that occurs when tissues are injured by heat, toxins, trauma, or bacteria.
Vitamin E is also important to healthy T-lymphocytes (T-cells) — this vitamin increases T-cell levels by helping these cells to properly multiply, maintains T-cell membrane strength, and helps T-cells communicate with other cells. A recent IUBMB Life published paper reveals that poorly functioning T-cells could be revitalized with vitamin E supplements.
Vitamin E is a fat soluble vitamin, meaning that it gets stored in the liver and fatty tissues. Once stored, it tends to remain until needed. That — combined with the fact that there are many commonly eaten foods that are rich in vitamin E — means vitamin E deficiency is extremely rare. If you eat fairly healthy, or take even a very inexpensive multivitamin, you’re guaranteed to be set with your vitamin E needs.
- Sunflower seeds
- Sweet potatoes
- Green leafy vegetables
Copper and the Immune System
Copper deficiency has been linked to an increased risk of neurodegenerative and cardiovascular diseases, and impaired immune function. The exact mechanisms of how copper benefits the immune system isn’t known, but research confirms that it does indeed provide benefits.
Many cases of patients with increased infections and impaired immune cell development often have one commonality — a copper deficiency. One theory as to copper’s use as an immune system tool is that white blood cells that surround invading pathogens boost the copper levels of these intruder cells in order to break them down and kill them.
It doesn’t take a lot of copper to meet the recommended daily requirement, so if you eat any of the foods in the following list you’re most likely all set.
- Organ meats (such as liver and kidneys)
- Shellfish (such as oysters and lobster)
- Sesame seeds
- Sweet potatoes
- Green leafy vegetables
Iron and the Immune System
It’s well-known that iron is a key part of hemoglobin — the red blood cell component that moves oxygen from the lungs to the rest of the body. That’s why fatigue usually accompanies an iron deficiency — a shortage of iron means not enough oxygen is being delivered to cells of the body.
What’s less-known about iron is that this metal is vital to immune system health. How important is it? One peer-reviewed research paper published in The Journal of Nutrition concludes that almost every organ and cell involved in immune response becomes restricted and impaired by an iron deficiency.
An iron deficiency especially degrades the innate response — the body’s first line of defense that indiscriminately attacks any new pathogen. That makes a person more vulnerable to disease and infection.
From the following list you can see that there are plenty of commonly consumed foods that are rich in iron, so it’s rare for iron deficiency anemia to be caused solely due to dietary factors. A person with this condition most likely has both a low-iron diet and has a contributing condition such as pregnancy, heavy periods, or gastrointestinal tract bleeding from stomach ulcers.
- Red meat and poultry
- Nuts and seeds
- Dark green leafy vegetables
- Beans and peas
- Iron-rich bread and cereal
- Figs, dates, and raisins.
- Tuna, sardines, and haddock
Zinc and the Immune System
Zinc is so important to a healthy immune system that it is sometimes referred to as the gatekeeper of immune function. Several studies show that when zinc is taken at the first signs of a virus or cold, the duration of that sickness is shortened. That’s why you’ll often find zinc as an ingredient in over-the-counter cold or flu medications.
Zinc also plays a significant role in supporting T-cells. T-cells, or T-lymphocytes — the special blood cells that target and attack various kinds of pathogens.
The food of a typical American diet — such as shown below — naturally include sufficient amounts of zinc, so zinc deficiency in the U.S. is rare.
- Red meat
- Shellfish (such as crab and lobster)
- Whole grains
- Sesame seeds
Spices and the Immune System
Spices have been used for thousands of years in traditional medicine systems such as Ayurveda (on the Indian subcontinent) and TCM (traditional Chinese medicine) as remedies and treatments for many different diseases and ailments. While slow to be accepted by modern Western medicine, it’s now acknowledged that several spices are beneficial to immune system health. There are a few reasons for this, but in general, immune-benefiting spices have at least two things going for them:
- Antioxidative: Many spices contain antioxidants that protect immune cells from the harmful effects of free radicals — unstable molecules that can damage cells of all types.
- Anti-inflammatory: Some amount of inflammation is good, as it helps in healing and repairing damaged tissue. But too much inflammation is bad. Some spices have anti-inflammatory properties that can block certain substances in the body that cause excess inflammation.
Cinnamon and the Immune System
Cinnamaldehyde is the compound that gives cinnamon its distinctive flavor and odor. Cinnamaldehyde is also known to have many medicinal properties — its an antibacterial, antifungal, and anti-inflammatory. Cinnamaldehyde, along with the many flavonoids (powerful antioxidants naturally occurring in many spices, fruits, and vegetables) in cinnamon, is effective in lowering inflammation levels should they rise too high.
Over time, many microorganisms (bacteria and viruses) may develop resistance to antibodies — the immune system’s defense system becomes less efficient at killing these invaders. Cinnamon is very interesting in that these microorganisms do not develop a resistance to it, making cinnamon even more powerful than some antibiotics (that microorganisms do develop a resistance to).
Garlic and the Immune System
For thousands of years garlic has been used the world over as a treatment for many health issues. It’s been used to treat tuberculosis, colds, hypertension, bronchitis, and, of course, to ward off vampires!
Garlic has antibiotic and antimicrobial properties that work to limit the growth of bacteria, viruses, and other unwanted organisms. It also contains a compound called allicin. Allicin is unstable, and when consumed it quickly breaks down and converts to other compounds. It turns out this is a good thing, because several of these compounds boost the number of virus-fighting T-cells.
Ginger and the Immune System
Ginger is another spice with a long history of us in traditional medicine. Ginger has been used to help fight the common cold, reduce nausea, aid digestion, and more. The unique flavor and odor of ginger come from its many natural oils.
Medicinally, the most important of the ginger oils is gingerol. Gingerol has powerful antioxidant and anti-inflammatory properties. Gingerol is particularly good at fighting inflammation in joints, bones, and muscles.
Another immune-boosting compound in ginger are chemicals called sesquiterpenes. Sesquiterpenes have calming properties, and they also assist in cellular repair, act as antioxidants to fight free radicals, and provide protection from harmful microbes. Sesquiterpenes also provide another health benefit — they have the ability to cross the blood-brain barrier (a network of closely spaced cells that prevent harmful substances from reaching the brain) to contribute to neurological health.
Turmeric (Curcumin) and the Immune System
Ginger is a spice that’s good for the immune system, so it would make sense that turmeric is as well. That’s because turmeric comes from the root of a plant in the ginger family. Like ginger, turmeric has been used medicinally for thousands of years.
Curcumin is the main active ingredient in turmeric. Curcumin gives turmeric its distinctive orange-yellow color, and, more importantly, is a very potent anti-inflammatory and antioxidant.
Curcumin is known to be a potent immunomodulatory agent — a substance that stimulates or suppresses the immune system. Curcumin can modulate (modify, or control) the activation of T-cells, B-cells, and macrophages (a type of white blood cell that removes dead cells, kills microorganisms, and stimulates other immune system cells).
That’s some pretty powerful stuff, but there’s more. Curcumin increases brain levels of the growth hormone brain-derived neurotrophic factor, or BDNF — an action that can delay, or possibly even reverse, many age-related brain function issues.
Being both an immune system booster and a nootropic (a compound that enhances cognitive functions) makes curcumin a very popular, and powerful, nutritional supplement. Curcumin is extracted from turmeric root, so calling the supplement curcumin is more accurate than calling it turmeric — but you’ll find similar supplements labeled as one or the other (or even both, as in turmeric curcumin). In all cases the ingredients listing will specify the amount of curcumin in the supplement.
Eating a varied diet that includes foods with enough nutrients, and nutrients of the right types, is a requirement for the proper function and health of all cells — including immune cells.
A diet that is limited in variety, and thus lower in nutrients — such as the common Western diet that is high in refined sugar and ultra-processed foods, and low in fruits and vegetables — can result in chronic inflammation of the gut, a proliferation of unhealthy intestinal microorganisms, and a generally suppressed immune system.
A deficiency of even a single important nutrient can negatively affect your body’s immune response. If you become deficient in vitamin A, C, E, or B-complex, or copper, iron, or zinc, that one deficiency can greatly weaken your immune system. If you have a less than ideal diet, or have increased nutrient needs, consider getting in the habit of taking a vitamin or mineral supplement daily.