Three powerful Immune Boosters that aren’t Vitamin C

in Blog

Until recently, immune health was something we only thought about during the winter months with the fear of getting a cold or worse the flu from a coworker or more likely your child after it is passes through their entire classroom. I think it is safe to say that since the spread of COVID-19 a.k.a Coronavirus, most of us have had immune health on our minds going into this summer and will likely continue to for the near future. While vitamin C and even vitamin D are the classic go-to moves to improve immune health, they are not the only game in town. Below we are going to look at three other ingredients you should consider adding to your routine that have shown clinical evidence in improving immune health.

Fresh Vegetables in bowls on wood table


You have probably heard a lot of talk about probiotics, which are the live microorganisms that when consumed provide health benefits by improving or restoring your natural gut microflora. Probiotics are great and there are a lot of research suggesting their ability to improve everything from your immune system to cognition, though today we are going to look at the benefits of “PRE”biotics. Prebiotics are the compounds or “food” for your natural gut microflora / the probiotics that you take in. They are non-living, non-digestible ingredients that fuel the good probiotic microorganisms inside of us. A good way of looking at it, is that your gut microflora (or probiotics) are factories, prebiotics are the fuel for the factories. Since prebiotics are not digestible (by you) you do not have to worry about them being destroyed by your stomach acid etc., preventing them from getting to their final destination in a functional state. This is not the case for probiotics (which are alive) in which you have to worry about them being broken down / digested as they pass through the harsh environment of your Stomach and Duodenum (Beginning of small intestine) on their way to their home in your lower gut.

Most of the identified prebiotics consisted of plant derived carbohydrates such as fructans and inulins as well as other dietary fibers such as resistant starch and pectin (1,2,3,4).  Prebiotics have been researched extensively over the past decade with data suggesting its ability to improve and stimulate the growth of beneficial gut bacteria and enhance mineral absorption (5) and the immune system. The results of many of these studies suggest the use of prebiotics can improve the adaptive immune system, (6) and reduce the number of instances in which the use of antibiotics was necessary (7).

While there are many great prebiotic supplements on the market you can find prebiotics in many everyday foods such as onions, leeks, asparagus, wheat bran, bananas, mushrooms and Garlic (we will discuss next) and Garlic (8).

Garlic cloves in white bowl next to heads of garlic on wood table



Garlic a.k.a “Russian Penicillin”, “The Plant Talisman” (9), “rustics theriac” (cure-all) or if you grew up with an Italian mother like me, “Italian Gold”. Garlic has many names and a long history as a homeopathic remedy for everything from influenza to snake and insect bites (10). Ancient Indian healers used garlic for skin disease, cough and rheumatism; the ancient Israelis use the bulb as a parasite killer and to reduce blood pressure; it was even used in Northern Europe to help fight the plague, cholera and typhoid Fever. Wow! Is there anything garlic wasn’t used for back then?  The effectiveness of garlic for treating all those conditions is widely debated but the abundance of its use speaks volumes about its potential health benefits.

I was always told, “you can’t live in the past”, so let’s take a look at what more recent research says about garlic. In 2001, a 12-week study compared two groups of subjects during the cold/flu season in which one group took a placebo (good old sugar pill) and the other an allicin capsule. Allicin is the sulfur-containing compound in garlic that causes the smell of garlic and is suspected to provide many of its positive health effects. The group taking the allicin capsules reported significantly less cases of a cold (24 compared to 65 for placebo) as well as reduced length of cold symptoms (1.52 days for allicin compared to 5 for placebo) (11). An even more recent study in 2012 compared the use of a placebo to aged garlic during cold and flu season to determine garlics ability to reduce the chances of becoming sick. By aging garlic it loses some of its pungent smell which is why most garlic supplements on the market are aged garlic. Between the two groups, there were no significant difference in the number of incidences of becoming sick, but there was a 61% reduction in the duration of being sick and a 21% reduction in the number of symptom in the group receiving the aged garlic (12).

The use of garlic to boost your immune system seems very promising and I highly encourage its use, both from a health standpoint as well as its use as a seasoning (because it is delicious and can be added to just about any dish). While showing amazing health and immune benefits the World Health Organization recently noted that there is no evidence that garlic can fight the coronavirus as it simply has never been investigated. So add some garlic to your life but don’t expect it to cure all your issues and please don’t test the idea of using garlic to help with a snake bite!

White button mushrooms in white bowl on wood table



The last immune boosting ingredient that we are going to look at today are mushrooms. The name “Mushroom” is usually used for most fungi that have a stem and cap structure. While most mushrooms are edible and provide some great health benefits and nutrients (vitamin D, Ergothioneine, etc.), don’t just go around and sauté any mushroom you find in your backyard. Some can be highly toxic, even deadly while others contain Psilocybin which has psychedelic properties “totally groovy man!”

For the time being we are going to going to look at the white button mushroom which is a type of mushrooms you can find at your local grocery store or farmers market. As previously mentioned, mushrooms are a great source of Vitamin D which is important for immune health and part of the reason Mushrooms are on this list (13).

Consuming white button mushrooms daily has been observed to make the immune system more alert through the increase in production of immune cells (14) as well as secretory immunoglobin A (sIgA), which is a type of nonspecific antibody (15). It is suggested that this increase in immune system alertness is a “gut immunostimulatory effect” provided by the prebiotic b-D-glucans found in white button mushrooms (14, 15).  Other studies suggest that mushrooms may increase the immune response once activated (16). This was tested out further to see if the consumption of white button mushrooms can improve the effectiveness of a vaccine. Lo and behold, the test group that receive both the vaccine and mushrooms had a significantly better immune response when exposed to the pathogen compared to the group that received the vaccine alone (17). These results may suggest that consuming mushrooms will not only reduce your chances of being sick and length of the sickness, but also improve your ability to fight the same sickness if you encounter it again. Yummy delicious and immune boosting!


Closing Thoughts

As you can see there is a connection to all three of these ingredients in the aspect of having some prebiotic effect which only stresses the importance of a healthy diet and a healthy gut. At some point we will take a deeper look into gut health, its importance and what is really going on. In the meantime, it cannot hurt to start adding more garlic and mushrooms to your diet, especially during the winter months. Also, while we discussed button mushrooms specifically, the health benefits of mushrooms do not end with them. As a reminder if you are afraid of garlic breath you can buy aged garlic .



  1. Gibson G, Hutkins R, Sanders M, Prescott S, Reimer R, Salminen S, Scott K, Stanton C, Swanson K, Cani P, Verbeke K, Reid G. 2017. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nature Reviews Gastroenterology & Hepatology. 14:491-502.
  2. Slavin J. 2013. Fiber and Prebiotics: Mechanisms and Health Benefits. Nutrients. 5(4):1417-1435
  3. Zaman S, Sarbini S. 2015. The potential of resistant starch as a prebiotic. Critical Reviews in Biotechnology. 36(3):578-584.
  4. Gómez B, Gullón B, Remoroza C, Schols H, Parajó J, Alonso J. 2014. Purification, Characterization, and Prebiotic Properties of Pectic Oligosaccharides from Orange Peel Wastes. Journal of Agricultural and Food Chemistry. 62(40):9769-9782.
  5. Scholz-Ahrens K, Schrezenmeir J. 2007. Inulin and Oligofructose and Mineral Metabolism: The Evidence from Animal Trials. The Journal of Nutrition. 137(11):2513S-2523S.
  6. Lomax A, Calder P. 2009. Prebiotics, Immune Function, Infection and Inflammation: A Review of the Evidence. British Journal of Nutrition. 101(5):633-658.
  7. Lohner S, Küllenberg D, Antes G, Decsi T, Meerpohl J. 2014. Prebiotics in healthy infants and children for prevention of acute infectious diseases: a systematic review and meta-analysis. Nutrition Reviews. 72(8):523-531.
  8. Moshfegh A. Friday J. Goldman J. Chug Ahuja J. 1999. Presence of Inulin and Oligofructose in the Diets of Americans. The Journal of Nutrition. 129(7):1407S-1411S.
  9. Petrovska BB and Cekovska S. “Extracts from the history and medical properties of garlic.” Pharmacogn Rev. 2010 Jan-Jun;4(7):106–110.
  10. Bayan, L; Koulivand, PH; Gorji, A (January 2014). "Garlic: A Review of Potential Therapeutic Effects". Avicenna Journal of Phytomedicine. 4(1): 1–14. PMC 4103721PMID 25050296.
  11. Peter J. 2001. Preventing the common cold with a garlic supplement: A double-blind, placebo-controlled survey. Advances in Therapy. 18:189-193.
  12. Nantz M, Rowe C, Muller C, Creasy R, Stanilka J, Percival S. 2012. Supplmentation With Aged Garlic Extract Improves Both NK and γδ-T Cell Function and Reduces the Severity of Cold and Flu Symptoms: A Randomized, Double-Blind, Placebo-Controlled Nutrition Intervention. Clinical Nutrition 31(3):337-344.
  13. Kalaras M, Beelman R. Elias R. 2012. Effect of Postharvest Pulsed UV light Treatment of White Button Mushrooms (Agaricus bisporus) on Vitamin D2 Content and Quality Attributes. Journal of Agricultural and Food Chemistry. 60(1):220-225.
  14. Ren Z, Guo Z, Meydani S, Wu D. 2008. White Button Mushroom Enhances Maturation of Bone Marrow-Derived Dendritic Cells and Their Antigen Presenting Function in Mice. The Journal of Nutrition. 138(3):544-550.
  15. Jeong S, Koyyalamundi S, Pang G. 2012. Dietary intake of Agaricus bisporus white button mushroom accelerates salivary immunoglobin A secretion in healthy volunteers. Applied Nutritional Investigation. 28(5):527-531.
  16. Yu S, Weaver V, Martin K, Cantorna M. 2009. The effects of whole mushrooms during inflammation. BMC Immunology. 10 (12).
  17. Wang J. Niu X. Du Z. Smith D. Meydani S. Wu D. 2014. 2014. Dietary Supplementation with White Button Mushrooms Augments the Protective Immune Response to Salmonella Vaccine in Mice. The Journal of Nutrition. 144(1):98-105.