fly, common cold, garlic

How Garlic Boosts Your Immune System

It’s time to bring out the garlic – seriously. Not only is garlic an amazing flavor booster but it also helps to give your body a major boost to your immune system as well. For those that skip on getting the flu vaccine (and even for those that do get it), you should really think about making garlic a big part of your diet if you’re looking to prevent the flu, common cold, or if you’re trying to stay away from becoming infected in general.

Boosting Your Immune System With Garlic

I love garlic. Not only do I love its flavor but it seriously has quite the plethora of health benefits. One of my favorite things about garlic is that garlic really vamps up your immune system. Working in the emergency room during the winter months exposes me to hundreds of people who are infected with the invluenza virus or some other sort of respiratory infection. I don’t get the flu vaccine (even though in my field it’s heavily recommended) so staying as healthy as possible is a necessity for me. One of my favorite ways to make sure my immune system is functioning is by frequently including garlic as a part of my diet.

So, How Does Garlic Boost The Immune System?

One of the active components is garlic is a compound called alliin. When garlic is crushed or chopped it releases an enzyme called alliinase. Alliinase turns the alliin inside the garlic into something called allicin. This allicin is a highly unstable compound that breaks down to form sulfur containing compounds which are responsible for having a drastic effect on the immune system (2).

Garlic Reduces Inflammation

Let’s be honest here, most of our bodies probably have some degree of inflammation going on, whether it’s from stress caused by lack of sleep, stress at work, too much sugar in the diet, or what have you. The point is, inflammation and stress in the body triggers an immune response. If our immune system is constantly overworked, what happens when a virus or bacteria comes along to make a home inside our bodies with a weakened immune response? We get sick. Symptoms are even more severe or last even longer with a weakened immune system. Several studies on garlic has shown that the organosulfur compounds have found to inhibit the activity of inflammatory enzymes inside the body. In addition to that, the compounds in garlic can help inhibit our white blood cells (responsible for working against infections) from releasing inflammatory signaling molecules (3,8).

Garlic For Flu Prevention?

Most research on garlic takes a look at the overall effect that garlic has on the immune system. One study took a look at garlic and how it relates to flu and common cold prevention. Over a twelve week period from the months of November to February, volunteers took a placebo pill or an allicin-containing garlic pill. Those who took the “garlic” pill had significantly fewer cold like symptoms and when they did get cold like infections, they had a shorter duration of symptoms than those who didn’t take the garlic pill. Just in case you’re curious, the supplement in question was developed by a company that claims to have developed stabilized allicin called AllicinMax (6).

In addition to the AllicinMax study, garlic was specifically looked at against certain types of virus strains. Garlic was shown to have anti-viral activity against influenza-B (although I’m not sure against what strains) and para-influenza virus type 3 (7). Para-influenza viruses are a breed of viruses responsible for respiratory infections that produce flu like symptoms.

Other Ways Garlic Boosts The Immune System

In one study of people who had inoperable cancers (which already puts a strain on your immune system), people took a garlic extract for six months. Those with colorectal, liver, or pancreatic cancer showed an increase in immune function (11). Garlic has also shown to stimulate the type of cells in the body that are responsible for immunity (interleukin-2), enhance your body’s natural killer cells, and killer cell activity (9,10). Not bad, eh? Who doesn’t need an immune system boost from garlic?

Another interesting study came out involving garlic in mice. A group of mice had their thymus glands removed shortly after birth. In humans, the thymus gland is responsible for making all of the body’s T-cell’s which help in your immune response. Naturally, without a thymus, your immune function would become severely impaired. In this study, the mice without the thymus gland were fed a diet that contained 2% aged garlic extract and what was found is that the mice had a significantly increased immune system, even without the thymus gland. Without having a thymus gland to make T-cells, the aged garlic extract prevented a reduction of antibody production (12).

Get The Most From Your Garlic

Raw garlic is the best way to get a boost to your immune system. Actually, in order to get any benefit from Allicin in garlic, the garlic cells need to be damaged…or crushed. The crushed garlic releases allicin and allicin is highly unstable and quickly converts to its sulfur containing compounds that have the health benefit. Cooking garlic for even as little of sixty seconds of microwave heating or cooking garlic in the oven can damage the allicin (1,3). The same goes for boiling.

The Key: Let your garlic stand for ten minutes after it has been crushed before you eat it. Also, the longer garlic sits after it has been crushed (hours, days, etc.), the more it loses its immune boosting effects.

How Much Garlic Do You Need To Boost Your Immune System?

Approximately one clove of garlic is about four grams and is about 1% alliin. One to two cloves of garlic a day should be fine (13). The World Health Organization recommends 2-5 grams of fresh garlic (about one clove), 0.4-1.2 grams of dried powder, 2-5 milligrams of oil, 300-1000 milligrams of extract, or other formulations containing 2-5 milligrams allicin (2). However, see my thoughts on garlic supplemention, below.

Garlic Supplementation

I wouldn’t recommend it. The allicin containing compound in garlic is really unstable. The chances of garlic extract pills still being stable after being exposed to long periods of light and temperature differences are likely to inactivate the compounds and make your garlic supplements completely useless. Depending on the heating and processing involved with making the supplements, there might be different levels of the compounds responsible for the health benefits – or worse yet, none at at all (4,5). If your garlic supplement contains alliin instead of allicin, it needs alliinase to break down the alliin into allicin inside of your stomach. The problem is, alliinase likely won’t be found in your stomach. The environment is too acidic and inactivates alliinase. If you think garlic supplementation is for you, at least try to ensure that your pill is enteric coated. Enteric coating helps to keep the pill from breaking down in your stomach so rapidly. As for me, I will stick with raw garlic.

Summing Up Strengthening Your Immune System From Garlic

As with all foods, there is no ONE food that prevents everything. Including garlic as a part of an overall real food diet can help to strengthen your immune system. For the best effects that garlic has to offer, stick with raw garlic that has been chopped/crushed and has been allowed to sit out for about ten minutes. Skip the garlic supplements that just contain allicin – you’re missing out on all of the other healthy things that garlic has to offer.


1. Camargo, A., Cavagnaro, P., Galmarini, C., Simon, P. “Effect Of Cooking Garlic (Allium Sativum L.) Antiplatelet Activity and Thiosulfinates Content.” Journal of Agricultural and Food Chemistry. 21 February 2007. Web. 27 Oct. 2014.
2. Milner, J., Song, K. “The Influence On Heating The Anticancer Properties Of Garlic.” The Journal Of Nutrition. March 2001. Web. 27 Oct. 2014.
3. N.p. “Garlic.” Natural Standard – The Authority On Integrative Medicine. 2014. Web. 20 October 2014.
4. Higdon, J. “Garlic and Organosulfur Compounds.” Linus Pauling Institute – Oregon State University. 2008. Web. 27 October 2014.
5. N.a. “Garlic.” University of Maryland Medical Center. 26 Jan. 2011. Web. 27 Oct. 2014.
6. Josling, P. “Preventing The Common Cold With A Garlic Supplement: A Double Blind, Placebo-Controlled Study.” Advances In Therapy. July-Aug. 2008. Web. 27 Oct. 2014.
7. Gebreyohannes, G., Gebreyohannes, M. “Medicinal Values Of Garlic: A Review.” International Journal Of Medicine and Medical Sciences. Sep. 2013. Web. 27 Oct. 2014.
8. Auger, J., Dirsch, V., Haffner, T., Hartung, T., Kahane, R., Keiss, H., Trueman, L., Vollmar, A. “Garlic (Allium sativum L.) Modulates Cytokine Expression In Lipopolysachharide-Activated Human Blood Thereby Inhibiting NF-KappaB Activity.” The Journal of Nutrition. July 2003. Web. 27 October 2014.
9. Lamm, D., Riggs, D. “Enhanced Immunocompetence By Garlic: Role In Bladder Cancer and Other Malignancies. March 2001. Web. 27 October 2014.
10. Bergman, M., Bessier, H., Djaldetti, M., Punsky, I., Salman, H. “Effect Of A Garlic Derivative (Alliin) On Peripheral Blood Cell Immune Response.” International of Immunopharmacology. September 2001. Web. 27 Oct. 2014.
11. Fukuda, S., Ishikawa, H., Morimoto, K., Nishino, H., Otani, T., Saeki, T., Shimozuma, K., Suzuki, T. “Aged Garlic Extract Prevents A Decline Of NK Cell Number and Activity In Patients With Advanced Cancer.” The Journal Of Nutrition. March 2006. Web. 27 October 2014.
12. Moriguchi, T., Nishiyama, N., Saito, H., Zhang, Y. “Functional Relationship Between Age-Related Immunodeficiency and Learning Deterioration.” The European Journal Of Neuroscience. December 1998. Web. 27 October 2014.
13. N.a. Garlic. MedlinePlus: A Service Of The U.S. National Library Of Medicine National Institutes Of Health. 21 August 2014. Web. 27 October 2014.

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