Top 20 Immune Boosting Foods

Fighting the cold war, or its somatic equivalent, is not just for politicians—it’s for ordinary people, struggling to fend off the upheaval viruses can wreak. Your body’s immune system is a remarkable machine designed to protect you from harmful threats that may arise from outside or inside your own body. Overall, the immune system generates an ‘inflammatory response’ that can be specific to a certain area (think infection) or a generalized area (think fever). (1)

While our immune system always strives to rid us of foreign invaders, what makes people sick is a combination of bad luck—exposure to viruses or other pathogens—and the level of our resilience. Although you can’t control exposure, you can make dietary choices that give your disease-fighting cells some serious support.

Top 20 foods for immune health

Many people don’t realize just how significantly our diet can influence our immunity. The following 20 science-backed foods provide valuable ammunition for your own private cold war.

1. Elderberries

The berries and flowers of elderberry are fully loaded with immune-bolstering antioxidants and vitamins. Elderberry, a strong antiviral, is particularly effective at fighting upper respiratory infections.

In one study of adults with flu-like symptoms, those who took 15 ml of the elderberry syrup four times daily had their symptoms clear up roughly four days earlier than those who took a placebo syrup. (2)

dark chocolate

Dark chocolate contains high levels of flavonoids, antioxidants that protect our cells from damage and inflammation.

2. Chocolate

Not all chocolate is equally healthy. Milk and white chocolate, for example, have relatively few, if any immunity perks. The darker the chocolate, the greater the health benefits. Dark chocolate contains much higher levels of flavonoids, antioxidants that protect our cells from damage and inflammation.

Did you know?
A recent pilot study found that among participants who ate one dark chocolate bar every day for a week, the chocolate boosted immune-supportive white blood cells and reduced the genes involved in inflammation. (3)

3. Turmeric

This golden yellow, bitter spice plays a key role in curry dishes and has been used for centuries in Ayurvedic medicine to treat a range of inflammatory conditions, such as allergies, diabetes, and ulcers. Curcumin, the active compound in turmeric, is responsible for the bulk of its benefits because of its capacity to stimulate circulation.

For inflammation, studies have shown that curcumin changes immune system responses and blocks enzymes that can cause arthritis inflammation. (4)

4. Fatty fish

The star component of fatty fish—omega-3 fatty acids— has long been appreciated for lowering the risk of heart attacks, strokes, and death from heart disease. But a new spate of research investigates its potentially beneficial effect on the immune system as well. Wild salmon or smaller fish such as anchovies, herring, and sardines are high in omega-3s, while flaxseed oil is an alternative, plant-based source of omega-3s.

One study found that a high DHA fish oil concentrate can support healthy immune response in middle-aged obese adults. (5)

person adding ginger to tea

Ginger has strong anti-inflammatory and antioxidant effects that are crucial for a healthy immune system.

5. Ginger

Ginger is widely consumed worldwide; it has been used for thousands of years in folk medicine, Traditional Chinese Medicine and Ayurveda. A pungent spice for both savory and sweet dishes, ginger boasts strong anti-inflammatory and antioxidant effects, the cornerstones of a healthy immune system.

One study examined the effects of ginger extract on the immune system cells and antibodies, thyroid hormones, and bloodwork in smokers compared to non-smokers. While both groups benefited from the ginger in different ways, non-smokers had enhanced amounts of antibodies in their blood, indicative of a fiercer response to infections. (6)

6. Garlic

Garlic is the edible bulb from a plant in the lily family, traditionally used for health reasons by people the world over. Garlic’s immune-boosting properties come from a heavy concentration of sulfur-containing compounds, such as allicin, found to significantly reduce inflammation.

A study that had some participants take garlic extract for 90 days found that the garlic group experienced reduced cold and flu severity, with a reduction in the number of symptoms, and less work/school days missed due to sickness. (7)

broccoli soup

Kale, spinach, and broccoli are top choices for fighting off colds and the flu.

7. Spinach/broccoli/kale

Greens such as kale, spinach and broccoli are more abundant sources of beta carotene than carrots or sweet potatoes, which makes them a top choice for fighting off colds and the flu. In the body, the liver converts beta carotene into vitamin A, which amps up the immune system by increasing the production of white blood cells. These excel at destroying foreign bacteria and viruses. Vitamin A also helps maintain the lining of the respiratory and digestive tracts, the body’s first lines of defense against pathogens.

A hearty body of research shows that eating these vegetables regularly stimulates the immune system and reduces oxidative stress. (8)

8. Matcha green tea

Matcha, produced when young green tea leaves are steamed and then ground into a fine bright-green powder, has a lush, almost sweet, vegetal flavor. Whereas both green and black teas are packed with antioxidants called flavonoids, matcha provides sky-high levels of a class of antioxidants called catechins, which studies suggest can amplify the immune function.

A study at the University of Colorado at Colorado Springs shows that catchetin concentration available from drinking matcha is 137 times greater than the amount of catchetin available from China Green Tips green tea and roughly three times higher than most green teas. (9)

9. Kefir/yogurt

Probiotics, found in foods like yogurt and kefir, are friendly bacteria thought to play a direct role in immune cell function (don’t forget you need to have some every day to get the benefit). These beneficial microbes take up residence in the belly’s microbiome, where they alter the pH of the intestinal environment to a level capable of warding off harmful bacteria.

A plethora of studies suggests regular consumption of kefir can help with fighting gut-disruptive bacteria. The most potent, probiotic-dense types of yogurt have “live and active cultures” printed on the label. Plain, unsweetened yogurt is a better choice than the pre-flavored varieties (you can sweeten it yourself if necessary), which come loaded with sugar.

A 2014 study published in the journal Nutrition found that for patients with rheumatoid arthritis, taking probiotic supplements significantly decreased disease activity and inflammation. (10)

10. Jalapeño peppers

Jalapeño peppers get their fiery spice from a compound called capsaicin, a burgeoning all-star of the functional foods world. When you eat a pepper, capsaicin causes the burning, warming sensation in the mouth. Capsaicin acts as an anti-inflammatory agent, and similar to probiotics, may ease arthritis symptoms and exert a disease-protective effect.

A 2015 study found that eating chilies and chili-containing foods regularly was associated with a decreased risk of premature death. Although more research on peppers is needed, the results of this large observational study suggest that participants who ate spicy foods almost every day had a relative 14 percent lower risk of death compared to those who consumed spicy foods less than once a week. (11)

11. Apples

Apple skin contains the flavonoid quercetin, a pigment that can help regulate the immune system and regulate allergic reactions. Quercetin, also found in grapes and wine as well as other produce, is known to kick the immune system into high gear, decreasing inflammation and stimulating anti-allergic activity.

A 2015 study proves the maxim: people who eat an apple a day use fewer prescription medications. (12) In another study that examined the food consumption of children living on the island of Crete, researchers found that children who ate apples, along with other fresh produce, as part of their core diet had greater protection against both allergies and asthma. (13)

father and daughter making fresh orange juice in kitchen

Citrus fruits like oranges and grapefruits increase the production of white blood cells, fortifying your immune system to help fight infections.

12. Citrus fruits

Most people instinctively turn to citrus fruits if they feel a cold coming on, whether it’s hot lemon and water, orange juice, or slices of fresh grapefruit. Considered a natural cold remedy, vitamin C-packed citrus increases the production of white blood cells, fortifying your immune system to fight infections like a champ. Citrus is also high in compounds called bioflavonoids, which attack cancer-causing free radicals.

Studies show that regular supplementation of a minimum of 1 to 2 grams/day of vitamin C per day can reduce how long cold symptoms last by an average of 8% in adults and 14% in children. This translates to roughly one less day of illness. (14)

13. Cranberries

Cranberries, a seasonal superfood, are crammed with nutrients linked to a lower risk of urinary tract infections, prevention of certain types of cancer, improved immune function, and decreased blood pressure. Traditionally eaten at Thanksgiving, it’s worth expanding your cranberry repertoire to include dishes year-round. Dried, unsweetened cranberries can be added to salads, oatmeal, muffins, and trail mix.

Cranberries contain high levels of antioxidant proanthocyanidins (PACs), which effectively prevent certain kinds of bacteria from adhering to the urinary tract walls and causing infections. One study found that people who took cranberry capsules twice daily for a year had a lower risk of getting a UTI. (15)

14. Fennel

A licorice-tasting culinary herb and medicinal plant, fennel is a lesser-known immune-boosting herb but very much worth adding to your stable of home remedies. Although rich in a wide variety of antioxidants, fennel boasts particularly high amounts of selenium, a mineral that stimulates our body’s response to infection.

One study found that among people between the ages of 57-84, supplementing with selenium enhanced the immune function and increased the production of killer T-cells, the white blood cells that attack infections and cancers. (16)

15. Sage

Many people are familiar with sage as an herb tied into bundles and used for smudging to create sacred space. But sage, which can also be made into tea, has been used for centuries as a traditional herbal remedy for sore throats, coughs, and colds.

Did you know?
Compounds in sage are particularly adept at breaking up mucus formation. Sage contains thujone, a terpene that functions as a potent antibiotic, stimulating your immune system and helping you recover faster from viruses.

A Swiss study found that using a sage/echinacea spray provided effective relief for acute throat irritation. (17) Another study found that drinking sage tea twice a day for four weeks improved participants’ lipid profile (the blood levels of cholesterol and fats in the blood) and antioxidant reserves, both key markers of a robust immune system. (18)

16. Shiitake mushrooms

Shiitake, one of the most popular mushrooms, contain polysaccharides, vigorous antiviral compounds equipped with substantial immune-boosting prowess. Shiitakes add a rich, earthy, savory taste that complements stir-fry, soups and stews.

In one study, participants who consumed either 5 or 10 g of mushrooms daily for a month had improved immune markers and less inflammation. (19)

17. Nuts

Nuts are stocked with vitamin E, a vitamin critical for a healthy immune system. Vitamin E, involved with nearly 200 biochemical reactions in your body, acts as an antioxidant, warding off cellular damage and invasive bacteria. (20) A one-fourth cup serving of almonds (two ounces), which is about 46 whole, shelled almonds, provides nearly 100 percent of the recommended daily amount of vitamin E.

According to the findings from the Nurses’ Health Study and the Physicians’ Health Study, which included nearly 120,000 participants, eating nuts was associated with increased longevity. While some people are concerned that nuts, because of their high fat content, can lead to weight gain, the high protein and fiber levels in nuts delay absorption and decrease hunger. (21)

oats in a wooden bowl

Oats are a great source of selenium and zinc, two key ingredients for a hardy immune system.

18. Oats

Whole oats contain beta-glucan, a compound that galvanizes our infection-fighting blood cells to take immediate action. Oats are also a great source of selenium and zinc, two key ingredients for a hardy immune system. To glean the most benefit from oats, choose steel-cut or old-fashioned rolled oats rather than the over-sugared instant varieties.

Several studies show that beta-glucan enhances the immune system’s ability to ward off a wide range of challenges such as bacteria, viruses, fungi, and parasites. (22)

19. Olive oil

This tasty oil, a core component of the Mediterranean diet, comes with many perks, not least of which is oleocanthal, an organic chemical that has comparable inflammation-busting properties to ibuprofen. For the immune system, two or three tablespoons of extra-virgin olive oil each day, drizzled on salads, vegetables, or grains, does wonders for immune health. When possible, choose extra-virgin olive oil, which has the highest concentration of antioxidants.

A study that compared the effects of daily consumption of olive oil to soybean, corn, and butter mixture found a significant increase in virus-busting white blood cells amongst participants who consumed olive oil. (23)

20. Beans

Beans, the staple protein in many parts of the world, is high in soluble fiber. This kind of fiber steps up the body’s anti-inflammation response into high gear. Beans also have an abundance of folate, a B vitamin required for the production of new immune cells.

Recent studies on mice have shown a variety of beans, especially black beans, contribute to gut health by improving the colon barrier function and increasing the ranks of healthy bacteria, a key factor in preventing gut-associated diseases. (24)

The bottom line

A wide variety of diverse foods, especially fruits and vegetables, can have a huge impact on your immune system’s resilience.

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