Discover the Best Foods for Boosting Your Immune System
No one likes to get sick, and most people know certain foods strengthen immune system health and help prevent and heal chronic diseases and acute infections.
Increasingly, clinical trials and scientific studies validate that some foods deliver more nutrition than others to boost immune function by increasing white blood cells and providing antioxidants that protect us from a wide range of health problems. 
But which foods have the best track record for keeping your immune system functioning at its highest level?
This article from the Havard Universitiy T.H. Chan (School of Public Health) gives you detailed information about the best immune system-boosting foods to keep you healthy or help you overcome existing health problems. In addition, you’ll find numerous links to the scientific research supporting the benefits of these foods, inclusing the NIH (National Institute of Environmental Health Sciences).
Even though there isn’t one food above all the others for its immune-boosting effects, there are two groups of foods that research supports as essential for a healthy immune system. Later in this article, we’ll tell you what they are.
1. The Best Foods for Immune Support
Eating a balanced diet of fruits and vegetables, high-quality protein, healthy fats, and healthy carbs is the optimum way of attaining the nutrition your immune system needs to function at its best. However, some foods provide more of the essential nutrients required by the human immune system than other foods. Also the BBC or the World Health Organization (WHO) analyze how important diet is for a healthy immune system.
Healthy eating habits that help prevent disease include an adequate intake of proteins, healthy fats, and immune-boosting vitamins and minerals, including:
- Linoleic acid
- Folic acid
- Vitamin E
- Vitamin C
- Vitamin D
- Vitamins B6 and B12
These nutrients work as antioxidants and are essential for a robust immune system. 
In addition to diet, if you need to strengthen immunity quickly, nutritional supplements can help overcome deficiencies and give you an extra boost toward more vigorous immune system health. However, there is no replacement for a healthy and varied diet – along with physical activity and other healthy lifestyle practices – for strengthening immune cells and other immune system responses.
The following foods are at the top of the list for having beneficial effects for supporting a resilient immune system and vibrant overall health.
2. Citrus Fruits
Citrus fruits contain high amounts of vitamin C and flavonoids, critical for healthy immune functioning. Vitamin C increases white blood cell count, and flavonoids perform as antioxidants that neutralize harmful intruders in the body. 
Citrus fruits include:
Our bodies cannot store vitamin C, so we need to consume adequate amounts of this vitamin daily through foods or dietary supplements.
3. Fresh Ginger
Ginger root is related to turmeric, another powerful healing herb discussed later in this article. Ginger has a long tradition in Ayurvedic and other traditional healing practices for many health conditions.
Ginger contains a variety of substances called gingerols that give this herb its spicy flavor and provide antioxidant, anti-inflammatory, anti-bacterial, and anti-viral effects that support the immune system’s response to a wide range of illnesses. 
Ginger is a versatile herb you can use in all these ways:
- Stir fry
- Steeped in hot water for tea
- Used in a glaze for chicken or fish
- Added to deserts and hot chocolate
4. Garlic and Onions
Garlic and onion are two of the most popular ingredients found in recipes worldwide, and there is a good reason for this. These two vegetables add aromatic and delicious flavors to many dishes. They also contain compounds that fight infection to help prevent the common cold and reduce illness during the flu season. 
Additionally, garlic and onions are among the most abundant food sources of sulfur compounds that are crucial for the body’s production of certain amino acids. In one research study, participants who took a garlic supplement had half as many incidences of the common cold as those who did not. 
Garlic and onions are also prebiotic foods that nourish healthy bacteria in the digestive system.
5. Sweet Potato, Carrots, Apricots, and Tomatoes
These foods all share the characteristic of having yellow or red-colored flesh, indicating they contain high amounts of vitamin A and beta carotene.
Vitamin A and beta carotene have antioxidant effects crucial for human health, and vitamin A is also essential for healthy eyes and vision. 
Apricots and tomatoes also contain significant amounts of vitamin C, and sweet potato is an excellent source of fiber that aids with elimination.
6. Broccoli, Cabbage, Kale, and Cauliflower
Broccoli, cabbage, cauliflower, and kale are all related to one another in the cruciferous plant family. They are all abundant sources of antioxidants, vitamins C and E, fiber, beta carotene, and sulfur compounds. Vitamins C and E are both essential nutrients for immune system health. 
These vitamins easily degraded when exposed to high heat and are best lightly cooked to maximize these critical nutrients in the dishes you prepare.
Broccoli sprouts are also highly nutritious and provide even more health benefits than fully-grown heads of this vegetable. In addition, broccoli sprouts are fast and easy to grow at home.
7. Pomegranate and Pomegranate Extract
Recent research into the benefits of pomegranate juice and extracts shows that this fruit is loaded with antiviral substances that aid the immune system in resisting viral infections. Pomegranates also contain a hefty dose of vitamin C. 
Other research shows that compounds in pomegranates inhibit the growth of many types of bacteria, including Listeria, Staphylococcus aureus, and E coli.  Pomegranates might also assist immunity as prebiotics that support the growth of beneficial bacteria in the gut. 
8. Nuts and Seeds
Vitamin E is an essential vitamin for optimum immune response, and some of the best sources of this nutrient are nuts and seeds such as
- and sunflower seeds.
Vitamin E is a fat-soluble compound, which means it requires the presence of short-chain fatty acids for proper absorption. Nuts and seeds contain high amounts of these healthy fats, assisting this vitamin in getting into the body where it plays a crucial role in preventing disease.  Avocadoes are another excellent source of vitamin E.
Mushrooms are a delicious and versatile food. They also boost immune response because they contain high levels of vitamin D and selenium, a trace mineral needed by the immune system for optimum functioning. 
Certain types of mushrooms are an excellent source of vitamin D, including shitake, oyster mushrooms, and button mushrooms. Vitamin D is an essential nutrient used by the immune system, and many people have sub-optimum levels of this vitamin. 
You can increase the amount of vitamin D in some types of mushrooms by exposing them to sunlight before eating them. 
10. Oily Fish and Shellfish
Another crucial mineral for immune system health is zinc, and an excellent source is fish and shellfish. Oysters are one of the best dietary sources of zinc, with six medium-sized oysters providing nearly 300 percent of the daily recommended amount of this mineral. 
Oily fish is another good source of zinc, along with healthy omega-3 fats and high-quality protein. Oily fish include:
Poultry, red meat, and beans also contain modest amounts of zinc.
Turmeric is a spice widely used in Indian cuisine, such as curry, giving this dish its characteristic yellow color. Studies of this herb reveal it has powerful anti-inflammatory effects, making it a popular alternative medicine and integrative medicine remedy to fight inflammation associated with arthritis.
The active ingredient responsible for the health benefits of turmeric is curcumin, and animal studies suggest curcumin has a beneficial effect on boosting immunity. You can also take curcumin as a supplement. 
Eggs are an excellent source of easy-to-digest and inexpensive protein that benefits immune response. In addition, eggs contain vitamins D and E, zinc, selenium, and healthy omega-3 fats, and all of these nutrients are crucial for robust and resilient immune health. 
13. Green Tea
Green tea contains substantial amounts of multiple antioxidants, flavonoids, and L-theanine, an amino acid that supports the body’s T cells. T cells are a vital cellular component that fights off invading viruses. 
Black tea contains smaller amounts of these beneficial compounds. However, the fermentation process of making black tea destroys some of the beneficial compounds, making green tea a more effective beverage for supporting immune health. Green tea also has substantially less caffeine than black tea.
The dark red color in berries is associated with a flavonoid called anthocyanin, another potent substance for supporting a resilient immune system. Multiple studies show that flavonoids boost immune functioning and help prevent respiratory tract infections. 
Numerous studies have been done on the healing effects of elderberry, finding that these fruits have a potent positive impact on strengthening the body’s resistance to viral infections. 
However, elderberries should not be eaten raw due to mild toxins that can cause stomach upset. Instead, use elderberry extract or boil dry elderberries for a delicious, immune-function-supporting beverage.
15. Dark Chocolate
Dark chocolate is a delicious treat, and it’s also a food with substantial amounts of beneficial nutrients that support optimum health, including trace minerals like selenium, zinc, iron, copper, and magnesium. 
The most healthful chocolates are those with a high percentage of cocoa because they contain less sugar and more of the beneficial nutrients needed by the immune system.
16. Chicken Soup
Much folklore touts the health benefits of chicken soup for speeding up healing from the common cold and seasonal flu. However, there is no specific scientific research into whether or not this is true.
Nonetheless, a warm bowl of homemade chicken soup may have benefits for the immune system because this dish typically contains many of the immune-healthy foods on this list. These beneficial foods include onion, garlic, carrots, mushrooms, herbs and spices, and, of course, chicken, a source of zinc and vitamin B6, an essential vitamin for immune health. 
In addition, the warm liquid in a bowl of soup helps replace fluids and electrolytes, preventing dehydration and assisting the body in removing toxins when you’re sick.
Chicken soup, or a plant-based version filled with vegetables from this list, is also psychologically beneficial for many people because of its reputation for nurturing and healing. A substantial body of research shows that a positive mental state boosts immune system function. 
17. Probiotic and Prebiotic Foods
While you cannot achieve optimum immune response by eating a single food, research over the last decades repeatedly validates these two food groups are a core component necessary for good immune functioning. 
Probiotics are Beneficial Bacteria
Probiotics are foods that contain active cultures of gut-healthy beneficial bacteria that are the starting point of healthy digestion and getting the most nutrition out of all foods you eat.
Probiotics help the body access the nutrients in all the foods we eat, making these nutrients more available for absorption by the digestive tract.
In addition, healthy probiotic bacteria also appear to boost immune function in multiple ways that we are just beginning to understand. 
Probiotic foods include:
- Live and active culture yogurt and kefir
- Fermented foods like natural sauerkraut and kimchi
- Kombucha tea
- Naturally fermented pickles
Cooking methods matter when it comes to the preparation of probiotic foods. Heat can destroy the good bacteria, so lightly cook or eat these foods without cooking them for the most benefit.
Prebiotics Feed Healthy Bacteria
Prebiotic foods are especially beneficial for feeding probiotic bacteria and helping them to thrive.
Prebiotic foods include:
- Garlic, onions, and leeks
- Leafy greens, especially dandelion greens
- Slightly green bananas
- Jerusalem artichokes
The fiber in these foods nourishes the probiotic bacteria, and cooking prebiotic foods does not decrease their effectiveness. Regularly eating probiotic and prebiotic foods is one important step you can take to optimize your gut health and get the most benefit from all the foods you consume. 
18. Which Immune Boosting Foods are Right for You?
Different individuals have different food preferences, and it’s essential to choose foods to match your tastes and body chemistry. In addition, some people have allergies or other intolerances to particular foods, and otherwise healthy foods can cause adverse reactions for some people.
One way of determining which foods are best for you is using a blood test like the Alcat Test for food intolerance. This blood test can assist you in understanding if certain foods are not suitable for your body chemistry, allowing you to focus on the most appropriate foods to support your health.
How to Improve Immune System Health with Blood Testing
The Alcat Test is a validated method for investigating a person’s immune reaction to foods, food additives, drug ingredients, herbal supplements, molds, and biogenic amines. This test can be helpful for people who want to fight inflammation using reliable information about what foods, supplements, and other substances might be adversely affecting their health.
The Alcat Test has been validated in double-blinded studies for determining specific dietary recommendations relevant to food intolerances that might help prevent disease.
Also the nutrient stats can effectively be checked with a cellular blood test by Cell Science Systems’ Cellular Nutrition Assay. Other blood tests (serum tests) are usually based on the population average. However, may people may fall through the average grid, for example:
- Women – fertility, pregnancy, lactation, perimenopause, menopause, etc.
- Sports nutrition, situations that are long term challenging and create stress.
- Before and after surgical interventions
- Weight management, obesity
- Burnout, fatigue, depression, mood swings, low vitality
- Chronic illness and/or metabolic syndrome (elevated blood pressure and blood sugar, excess body fat, abnormal cholesterol levels)
- Some genetic predisposition, e.g. a genetic detoxification disorder (methylation disorder)
The presence of micro-inflammation or poor gut health can also have an individual impact on micronutrient use. A 2020 study suggests that high food intolerance (determined at the cellular level using the Alcat Test) is associated with higher nutrient deficiency, a stronger oxidative stress response and lower resistance to oxidative stress. 
19. Conclusions about Foods that Strengthen Immune System Health
The best ways to boost your immune function are by eating healthy foods that are right for your body, getting sufficient high-quality sleep, and living a healthy lifestyle. In addition, supplements can fill in the gap if you have health conditions or deficiencies that increase your need for certain nutrients. Alcat blood testing can help determine if certain foods and other substances interfere with your optimum health.
The immune system is a complex network of immune cells such as white blood cells, T cells, organs, tissues, healthy gut bacteria, and metabolic processes. In the last few decades, researchers have begun unraveling how our immune systems work and what foods and healthy lifestyle practices are most central for preventing acute and chronic illness.
So far, scientific research backs-up the idea that some foods benefit immune system health more than others because of the nutrients they contain. In addition, the beneficial role of probiotic and prebiotic foods for getting the most nutrition out of what you eat is now evident.
However, not all foods are suitable for all people, and the Alcat Test can help you understand which foods are the best choices for you to boost your immune system function for optimum health.
German version of this article: Immunssystem stärken mit gesunder Ernährung
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Literature / Sources
 Steele I, Allright D, Deutsch R; A randomized observational analysis examining the correlation between patients’ food sensitivities, micronutrient deficiencies, oxidative stress response and immune redox status. Functional Foods in Health and Disease. 2020; 10(3): 127- 138. DOI: https:/doi.org/10.31989/ffhd.v10i3.695