12 Immune Boosting Foods
Published: May 2020
As a registered dietitian, people often ask me about foods to boost the immune system. In general, fruits, vegetables and herbs are always going to be healthy choices. But some foods in particular stand out as superfoods when it comes to their impact on the function of our immune system. This is due to specific vitamins, minerals and other active compounds called phytonutrients they contain that play a role in how well our immune cells work.
So check out this list of foods to eat more of and start to incorporate them into your weekly shopping list—your immune system will thank you!
Immune Boosting Food List
1. Asparagus
Immune boosting nutrients: Vitamins A, C, E, zinc, protein, selenium, quercetin
The green (and sometimes purple or white) spears of asparagus are packed with a variety of vitamins, minerals, fiber and phytonutrients—including the mineral selenium, which supports the immune system.
Intake of selenium may improve the function of our Natural Killer (NK) cells, part of our body’s innate (first line of defense) immune system responders. Having a selenium deficiency can lead to increased susceptibility to infection, so make sure you’re getting enough.
One cup of asparagus provides around 11 mcg of selenium, and while the RDA of selenium is 55 mcg. Life Extension scientists suggest 200 mcg daily for optimal health.
2. Garlic
Immune boosting nutrients: Allicin, and small amounts of selenium & vitamin C
Garlic appears to enhance the immune system by stimulating immune defenders—macrophages, NK cells and others, while also exerting anti-inflammatory effects. Macrophages engulf and destroy harmful pathogens.
Allicin is a phytonutrient found in garlic that may help protect against viral infection by enhancing both the innate and adaptive immune responses. Our adaptive immune cells are able to recognize and act against previous offenders.
If you need a recipe idea that packs a potent punch of garlic, make pesto!
3. Ginger
Although it doesn’t offer much in the vitamin and mineral department, ginger reduces inflammation, may support respiratory health and helps ward off bacterial and fungal infections. So spice up your life with some ginger tea or a stir-fry!
4. Honey
Similarly, honey has small amounts of nutrients—but big benefits! Its ability to fight against bacteria is what makes this sweet substance stick the list. Plus, honey’s soothing properties come second to none when paired with some tea.
5. Kefir
Immune boosting nutrients: Probiotics, protein, vitamins A & D
Certain yogurts and other fermented foods contain probiotics. Kefir is a drinkable yogurt-like beverage that tends to have high amounts of probiotics. Just be sure to check the label first—you want to make sure there’s enough of that good bacteria in there. Probiotics are living microorganisms that can influence the functioning of our immune system when ingested in sufficient amounts. If you need a dairy-free source of probiotics, opt for kimchi!
Clinically studied strains that may prevent infections include Lactobacillus rhamnosus LR05 and Lactobacillus plantarum LP01. You likely won’t find these strains in foods, but other bacterial strains present in fermented foods may be beneficial as well!
6. Shiitake Mushrooms
Immune boosting nutrients: Zinc, vitamin D, selenium, beta-glucans
Animal and marine sourced proteins such as beef and oysters are high in zinc. While most of us get plenty of animal-based foods in our diet, upping our plant game with shiitake mushrooms, pumpkin seeds, garbanzo beans, oats, asparagus, spinach and lentils can serve as plant-based options for meeting our zinc needs.
Shiitake mushrooms are considered an excellent source of selenium because a ½ cup serving offers 19 mcg of selenium. Mushrooms are also some of the only plant-based sources of vitamin D, aside from algae.
With 1 mg of zinc per serving, they help nudge us toward our goal of at least 11 mg per day for men and 8 mg for women. Higher doses of zinc, upwards of 25-50 mg a day, are suggested for certain health goals, including immune system strengthening. And one mushroom extract called AHCC may also help fight viral infections.
7. Oats
Immune boosting nutrients: Zinc, protein, beta-glucans
If oatmeal is part of your daily breakfast rotation, you’re in a good place. Oats contain beta-glucans which are non-digestible fiber that may improve innate immune response. Plus, certain types of fibers in oats may act as a prebiotic to help beneficial gut bacteria flourish.
8. Oranges
Immune boosting nutrients: Vitamin C, flavonoids, quercetin
When we think of getting our vitamin C, oranges and their juice are likely the first things to come to mind. This common citrus fruit is recognized for its vitamin C content but also has other important immune supporting nutrients, such as quercetin.
A review of clinical studies with different flavonoids, including quercetin, indicated that flavonoids may reduce the incidence of upper respiratory infections. Plus, quercetin appears to have some antiviral and anti-inflammatory effects.
Vitamin C is very well-known for its immune boosting effects and may shorten the duration of the common cold.
9. Pineapple
Immune boosting nutrients: Vitamin C, bromelain
Looking for more vitamin C foods? How about some pineapple? A 1 cup serving will offer you 79 mg of vitamin C, making it an excellent source. While the RDA ranges from 75–90 mg for women and men, Life Extension scientists suggest at least 500 mg of vitamin C daily for optimal health.
Aside from its vitamin C content, pineapple makes our list because it has an enzyme known as bromelain. Bromelain has a variety of useful functions but its ability to beneficially regulate factors related to our immune system is what makes it relevant here. Bromelain supports respiratory health, may reduce inflammation and helps prevent & clear infections.
10. Salmon
Immune boosting nutrients: Vitamin D, selenium, protein, omega-3 fatty acids
The omega-3 essential fatty acids in fatty fish such as salmon impact the function of our immune cells and have been shown to have antimicrobial effects. Salmon is also a good source of protein and has some vitamins and minerals.
A 4 oz serving of salmon provides over 500 IU of vitamin D. While this amount gets us well on our way to meet the 600 IU RDA, many health experts agree that the RDA once again falls short when it comes to vitamin D intake in supporting optimal health. Life Extension generally suggests 5000 IU of vitamin D daily for most adults in order to support optimal blood levels.
Having healthy vitamin D blood levels is essential for proper functioning of both our innate and adaptive immune system. Deficiency or insufficiency is strongly linked to more infections, and if we do get sick, worse outcomes—such as a more severe course of illness.
Vitamin D intake may reduce the incidence of respiratory infections by effectively raising our blood levels and may truly be our best bet for supporting optimal blood levels, since it is difficult to obtain enough vitamin D from food and sunlight alone.
11. Spinach
Immune boosting nutrients: Vitamin A, E, C, zinc, protein, selenium, chlorophyll
Spinach is jam-packed with nutrients! We often think of orange foods like carrots or sweet potatoes when we think of vitamin A, but spinach is actually an excellent source of this vitamin, too. This is important, because a vitamin A deficiency hampers our antibody responses, and if we do get sick, adequate vitamin A helps repair mucosal barriers damaged by infection.
Spinach is also rich in vitamin E, which acts as an antioxidant and may reduce infection incidence. Similarly, a deficiency impairs immune function.
12. Whey protein powder
Immune boosting nutrients: Immunoglobulins, sulfur-containing amino acids
Adequate protein intake is necessary to repair tissue and fight off infections. Whey is an excellent source of protein and is especially convenient for a quick smoothie after a workout or as a meal replacement.
A quality whey protein powder will also contain immunoglobulins and sulfur-containing amino acids. These nutrients may support a healthy immune response and antioxidant defense through intracellular conversion to glutathione.
Nutrition from food and supplements
So there you have it—some of the best foods to boost your immune system! Don’t feel bad if you can’t find enough room in your diet to fit all of these in, though; it can be especially difficult to get enough vitamin D, omega-3 fatty acids EPA and DHA, and probiotics from food alone. Supplementing a healthy diet with these nutrients can help you fill in the gaps.
References
- Burgess L. 15 foods to boost the immune system. Medicalnewstoday.com. Published July 10, 2018. Accessed May 4, 2021. https://www.medicalnewstoday.com/articles/322412
- Avery JC, Hoffmann PR. Selenium, selenoproteins, and immunity. Nutrients. 2018;10(9):1203.
- Arreola R, Quintero-Fabián S, López-Roa RI, et al. Immunomodulation and anti-inflammatory effects of garlic compounds. J Immunol Res. 2015;2015:401630.
- Schend J. 15 foods that boost the immune system. Healthline.com. Published April 30, 2020. Accessed May 4, 2021. https://www.healthline.com/health/food-nutrition/foods-that-boost-the-immune-system
- Chen O, Mah E, Dioum E, et al. The role of oat nutrients in the immune system: A narrative review. Nutrients. 2021;13(4):1048.
- Somerville VS, Braakhuis AJ, Hopkins WG. Effect of flavonoids on upper respiratory tract infections and immune function: A systematic review and meta-analysis. Adv Nutr. 2016;7(3):488-497.
- Müller S, März R, Schmolz M, Drewelow B, Eschmann K, Meiser P. Placebo-controlled randomized clinical trial on the immunomodulating activities of low- and high-dose bromelain after oral administration - new evidence on the antiinflammatory mode of action of bromelain: Immunomodulating activities of bromelain. Phytother Res. 2013;27(2):199-204.
- Harvard Health Publishing. How to boost your immune system. Harvard.edu. Accessed May 4, 2021. https://www.health.harvard.edu/staying-healthy/how-to-boost-your-immune-system
