Garlic (Allium sativum L.)

Garlic (Allium sativum L.)

Garlic is a bulbous plant that can grow up to 1.2 meters high. It is a member of the Lillaceae family like onions, chives, and shallots. It is easy to grow and does well in mild climates.

History

The medicinal properties of garlic have been studied and used since 3000 BC. Ancient civilizations including Phoenicians, Greek, Roman, and Viking used garlic to treat conditions like arthritis, heart conditions, skin disease, respiratory infections, diarrhea, insect bites, and tumors. Ancient Chinese societies believed consuming garlic would increase lifespan, and ancient Egyptians consumed garlic to obtain strength and stamina. In North America Native Americans used garlic in a tea to reduce flu like symptoms. Garlic was used to treat wounds in soldiers in the middle ages, and was used on the battlefield as recently as World War II to clean wounds.

Storage Suggestions:

Garlic will stay fresh for months if it is stored properly. The best way to store it is to keep the bulb intact. Once cloves have been broken off of the bulb, it is likely that it will only keep for another week. Store garlic in a dry, dark location. Light and moisture can cause mold to grow. If possible, store the garlic at room temperature in a dark place with air circulation, like a wire basket. Lastly, be sure to keep the garlic away from cold environments like the fridge. Within a couple days of being in the fridge it is likely that the garlic will sprout. Sprouted garlic is still edible, however it will be more bitter tasting.

Bioactive Compounds

Allicin (diallyl-thiosulfinate), is the most biologically active compound in garlic. Allicin is not present in raw garlic, however, it is rapidly produced by the enzyme alliinase acting on the compound alliin. Alliinase is activated by cutting or crushing garlic cloves, and then rapidly breaks down into a variety of organosulfur compounds that have been shown to be beneficial for health.2 Other bioactive compounds present in garlic are 1-propenyl allyl thiosulfonate, and allyl methyl thiosulfonate.

Effects of Cooking

Allinase can be inactivated by heat. In fact, heating an unpeeled clove of garlic in a microwave will destroy all alliinase enzyme activity. One study found that heating uncrushed garlic in the microwave for 60 seconds, or heating for 45 minutes in a convection oven destroyed the protective effects of garlic. However, crushing the garlic and allowing the garlic to stand for 10 minutes before heating preserved some of the protective effects. It is recommended that you let your garlic sit for 10 minutes before cooking with it to allow alliinase enzyme activity to happen.

Health Benefits

Antimicrobial Properties:

Garlic is known to have many health benefits, likely because of its antifungal and antimicrobial activity. Allicin is known to play a major role in garlics antimicrobial and antifungal affects. A study on rats noted that after feeding rats raw garlic extract for 4 weeks there was a decrease in Streptococci, coliforms, and Lactobacilli bacteria in the intestine. It is hypothesized that the reason garlic has such strong antimicrobial properties is due to allicin disrupting important physiological processes in microorganisms like RNA synthesis. One nutrition intervention study in humans noted that supplementation with aged garlic seemed to reduce the severity of cold and flu symptoms.

Antioxidant Activity:

Garlics bioactive compounds exhibit antioxidant activities. This likely contributes to why garlic is associated with anticancer and cardioprotective properties. Allicin has been proven to lower reactive oxygen species concentration in endothelial cells and increase glutathione concentration. Allicin also upregulates glutamate-cyctesine ligase, an enzyme essential to glutathione synthesis. Glutathione is an essential intracellular antioxidant responsible for preventing oxidative damage in the body. Allicin has also been found to scavenge hyrdroxyl radicals and inhibit superoxide production in the body.

Cardioprotective Properties:

As stated above, allicins antioxidant properties contribute to garlics cardioprotective properties. However, garlic has also been shown to protecting the cardiovascular system in other ways. Organosulfur compounds derived from garlic have been shown to inhibit platelet aggregation and reduce risk for thrombotic events. Organosulfur compounds inhibit mediators of the inflammatory response. While this processes is incredibly valuable in the prevention of many different chronic diseases, it is especially protective in individuals at risk for atherosclerosis and other cardiovascular disease.

Garlicky Harissa Recipe:

Recipe by Samin Nosrat

Ingredients:

·       8 dried guajillo chiles, seeds removed

·       ¼ teaspoon crushed red pepper flakes

·       1 teaspoon cumin seeds

·       2 garlic cloves, finely grated

·       1 cup olive oil

·       2 tablespoons sherry vinegar or red wine vinegar

·       Kosher salt

Directions:

Place guajillo chiles in a large heatproof bowl and pour in boiling water to cover. Let soak until softened, 40–45 minutes; drain.

Toast cumin seeds in a dry small skillet over medium heat until fragrant, about 2 minutes. Then finely grind with a spice mill or with mortar and pestle.

Drain chiles; transfer to a blender and purée, adding hot water one tablespoon at a time as needed until smooth. Strain chile mixture through a fine-mesh sieve; discard solids. Mix in ground cumin, crushed red pepper, garlic, oil, and vinegar. Season with salt and let sit 15 minutes before serving.

Sources:

1.           Bayan L, Koulivand PH, Gorji A. Garlic: a review of potential therapeutic effects. Avicenna J Phytomedicine. 2014;4(1):1-14.

2.           Rahman MS. Allicin and Other Functional Active Components in Garlic: Health Benefits and Bioavailability. Int J Food Prop. 2007;10(2):245-268. doi:10.1080/10942910601113327

3.           Rivlin RS. Historical Perspective on the Use of Garlic. J Nutr. 2001;131(3):951S-954S. doi:10.1093/jn/131.3.951S

4.           The Kitchn’s Guide to Storing Garlic. Kitchn. https://www.thekitchn.com/the-kitchns-guide-to-storing-garlic-231411. Accessed June 12, 2019.

5.           Song K, Milner JA. The influence of heating on the anticancer properties of garlic. J Nutr. 2001;131(3s):1054S-7S. doi:10.1093/jn/131.3.1054S

6.           Nantz MP, Rowe CA, Muller CE, Creasy RA, Stanilka JM, Percival SS. Supplementation 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. Clin Nutr Edinb Scotl. 2012;31(3):337-344. doi:10.1016/j.clnu.2011.11.019

7.           Garlic. Linus Pauling Institute. https://lpi.oregonstate.edu/mic/food-beverages/garlic. Published April 28, 2014. Accessed June 12, 2019.

8.           Appetit B. Garlicky Harissa Recipe. Bon Appetit. https://www.bonappetit.com/recipe/garlicky-harissa. Accessed June 12, 2019.