5 Immune System-Boosting Foods to Try

Studies have shown that malnutrition is associated with immune system dysfunction. As a result, ensuring you get the right nutrients is essential for building a strong foundation that allows your immune system to function at its best.

Several nutrients are known as critical parts of that equation. According to the Harvard T.H. Chan School of Public Health, those include vitamin C, vitamin D, iron, protein, selenium, and zinc.

There are many foods to choose from that contain important vitamins and nutrients, including these. Choosing the right foods can potentially assist with immunity. Here’s a look at five immune system-boosting foods to try.

Bell Peppers

Bell peppers are an excellent source of nutrients. In fact, bell peppers typically have more vitamin C in them than oranges. Red bell peppers are also excellent sources of beta-carotene. Plus, bell peppers contain less sugar than some citrus fruits, including oranges and grapefruits.

It is critical to keep in mind that the body doesn’t store vitamin C. As a result, it’s wise to consume  foods containing vitamin C every day. This will help you to meet the recommended minimums, which are 90 mg for men and 75 mg for women.

Some of the most popular and widely available citrus fruits include:

• Clementines
• Grapefruits
• Lemons
• Limes
• Oranges
• Tangerines

Garlic

Garlic has anti-inflammatory properties, and it benefits the immune system. Studies have shown that it stimulates specific cell types that are critical for immunity, and it may assist with the treatment or prevention of a variety of medical conditions.

Generally, there aren’t any daily consumption recommendations for garlic. However, if you use it to flavor foods, make sure to avoid heating it above 140°F. Temperatures above that can damage the allicin, the component in garlic associated with health benefits. Additionally, keep the quantities a bit limited, as too much garlic may cause stomach discomfort or other side effects.

Green Tea

Green tea contains polyphenols, which are components that play a role in disease prevention. Studies show that these components can positively impact immune system function. Plus, research indicates it may assist with a wide array of conditions, including improving cardiovascular health and supporting weight loss.

Another nutrient in green tea is L-theanine, an amino acid. Research has shown that L-theanine enhances immune function, and it may also assist with cognitive function and reduce stress-related symptoms in the body.

Turmeric

Inflammation in the body isn’t ideal for maintaining a capable immune system. Some studies show that a component of turmeric, called curcumin, can reduce inflammation based on its antioxidant activity. Research also indicates that turmeric modulates the activation of a variety of cells, which could have immune system benefits, too. Turmeric is a spice you can add to a number of dishes that may provide some health benefits.

Medical content reviewed by Brittany Stopa, MD MPH.

Further Reading

• Bourke CD, Berkley JA, Prendergast AJ. Immune Dysfunction as a Cause and Consequence of Malnutrition. Trends Immunol. 2016;37(6):386-398. doi:10.1016/j.it.2016.04.003
• Harvard T.H. Chan School of Public Health. “Nutrition and Immunity.” Accessed 31 May 2023. https://www.hsph.harvard.edu/nutritionsource/nutrition-and-immunity/
• National Institutes of Health Office of Dietary Supplements. “Vitamin C.” Last updated 22 Mar 2021. https://ods.od.nih.gov/factsheets/VitaminC-Consumer/
• Arreola R, Quintero-Fabián S, López-Roa RI, et al. Immunomodulation and anti-inflammatory effects of garlic compounds. J Immunol Res. 2015;2015:401630. doi:10.1155/2015/401630
• Cleveland Clinic. “The health benefits of garlic.” Published 02 Mar 2022. https://health.clevelandclinic.org/6-surprising-ways-garlic-boosts-your-health/
• Wang S, Li Z, Ma Y, et al. Immunomodulatory Effects of Green Tea Polyphenols. Molecules. 2021;26(12):3755. Published 2021 Jun 20. doi:10.3390/molecules26123755
• Nance CL, Mata M, McMullen A, McMaster S, Shearer WT. Regulation of innate immune recognition of viral infection by epigallocatechin gallate. The Journal of Allergy and Clinical Immunology. 2014;133(2):AB246. doi: 10.1016/j.jaci.2013.12.876
• Nagle DG, Ferreira D, Zhou YD. Epigallocatechin-3-gallate(EGCG): chemical and biomedical perspectives. Phytochemistry. 2006;67(17):1849-1855. doi:10.1016/j.phytochem.2006.06.020
• Bukowski JF, Morita CT, Brenner MB. Human gamma delta T cells recognize alkylamines derived from microbes, edible plants, and tea: implications for innate immunity. Immunity. 1999;11(1):57-65. doi:10.1016/s1074-7613(00)80081-3
• Hidese S, Ogawa S, Ota M, Ishida I, Yasukawa Z, Ozeki M, Kunugi H. Effects of L-theanine administration on stress-related symptoms and cognitive functions in healthy adults: a randomized controlled trial. Nutriets. 2019;11(10):2362. doi:10.3390/nu11102362
• Peng Y, Ao M, Dong B, Jiang Y, Yu L, Chen Z, Hu C, Xu R. Anti-inflammatory effects of curcumin in the inflammatory diseases: status, limitations and countermeasures. Drug Des Devel Ther. 2021;15:4503-4525. doi:10.2147/DDDT.S327378
• Jagetia GC, Aggarwal BB. “Spicing up” of the immune system by curcumin. J Clin Immunol. 2007;27(1):19-35. doi:10.1007/s10875-006-9066-7
• Brown ME. “Turmeric Benefits.” Johns Hopkins Medicine. Accessed: 16 Jun 2023. https://www.hopkinsmedicine.org/health/wellness-and-prevention/turmeric-benefits