Garlic: Health Benefits
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Latin Name: Allium sativum
Family: Amaryllidaceae
Garlic is actually a member of the lily family and is used worldwide as both a spice and a medicinal food. Throughout history, garlic has been used to treat a variety of ailments, ranging from headaches to hypertension to cancerous tumors (8). Around the world and across many centuries, garlic has been eaten before battle to protect Roman soldiers, smeared on the bodies of African fishermen to protect them from crocodiles, and used to ward off vampires and evil spirits in Europe (5).
Today, garlic is recognized for its antiviral, antibacterial, anticancer, anti-inflammatory, and immune-enhancing effects (8). Garlic contains many natural sulfur products including alliin, which is released when garlic is crushed or chewed (1). Garlic is for the most part nontoxic and inexpensive, making it a reliable treatment for most people worldwide.
Garlic is an excellent source of vitamin B6, and a good source of manganese, selenium, vitamin C, phosphorus, calcium, potassium, iron, and copper (6).
Health Benefits
Influenza Virus
The antiviral effects of garlic may help both prevent and treat the flu.
Studies have shown that it can prevent the likelihood of catching a cold or the flu, as well as reduce the length of time that one is sick and lessen the severity of symptoms (11).
Garlic may protect against other viruses, including: the human rhinovirus, cytomegalovirus, and herpes simplex (9).
Immunity
Garlic is believed to enhance the immune system due to its sulfur-containing compounds.
It has been shown to enhance the pathogen-attacking activity of T-cells, neutrophils, and macrophages and increase natural killer cell activity, thus improving the immune system (8).
Garlic is a prebiotic, which help to stimulate the growth of healthy bacteria in the gut and boost immunity (9).
Garlic may also help to prevent and reduce the severity and duration of upper respiratory tract infections (i.e. the common cold) (9).
Cardiovascular Health
Because of its ability to affect the process of atherosclerosis, garlic may protect against heart disease and stroke (8).
Garlic has been found to lower blood pressure, which is an important risk factor for cardiovascular disease, heart attack, and stroke (9).
Garlic supplements have also shown promise for lowering cholesterol in patients with slightly elevated levels (9).
Diabetes Treatment
Garlic and onions can be used in the treatment of diabetes due to their hypoglycemic effects (8).
Garlic has been shown to improve insulin sensitivity, reduce blood glucose levels, and improve lipid metabolism (7).
Garlic may also help with weight control by reducing body fat composition and suppressing weight gain (2, 10).
Cancer Prevention
Likely because of its impact on the immune system, garlic may indirectly help to protect against cancer.
Studies have found an inverse relationship between garlic consumption and cancer rates (8).
Safety Concerns
Stomach upset. Although garlic is nontoxic for the majority of individuals, it can cause stomach upset and heartburn in some, so it is recommended to take raw garlic with food.
Anticoagulant drugs. Garlic should be avoided by patients taking drugs or herbs that increase the risk of bleeding (1).
Pregnancy or breastfeeding. Garlic is considered safe in moderate doses while pregnant or breastfeeding (8).
Tips for Selection
Garlic can be consumed raw, cooked, as a supplement, or as an essential oil.
Consume raw garlic for maximum health benefits. Cooked garlic is still a healthful food, but will have reduced vitamin and enzyme content (3, 4).
Garlic must be crushed, minced, pressed, or chewed to release its beneficial properties.
While it is convenient to buy garlic in powder, flake, or paste form, it is not as healthful as fresh garlic (6).
If purchasing garlic supplements, choose enteric-coated tablets that are designed to pass through the acidic environment of the stomach before dissolving (1).
Serving Ideas to Add Raw Garlic to Your Diet
Crush a raw clove in a garlic press and mix it into olive oil or your favorite salad dressing.
Mix minced garlic into butter and spread on toast for quick garlic bread, or add to mashed potatoes.
Add raw garlic to homemade salsa, guacamole, or hot sauce.
When making a tomato sauce for pasta, add crushed garlic at the end when the sauce is finished cooking.
Soothe a sore throat and boost your immune system with a “tea” made from crushed garlic, lemon juice, honey, and hot water.
Try this recipe for a refreshing and nourishing gazpacho smoothie.
References
Jamison, J. (2003). Clinical guide to nutrition & dietary supplements in disease management. Victoria, Australia: Churchill Livingstone.
Kagawa, Y., Ozaki-Masuzawa, Y., Hosono, T., & Seki, T. (2020). Garlic oil suppresses high-fat diet induced obesity in rats through the upregulation of UCP-1 and the enhancement of energy expenditure. Experimental and Therapeutic Medicine. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6966189/
Kerr, G. (2019). Which is healthier, raw or cooked garlic? Livestrong. Retrieved from: https://www.livestrong.com/article/340975-what-are-the-health-benefits-of-raw-garlic-vs-cooked-garlic/
Lawson, L.D. & Hunsaker, S.M. (2018). Allicin bioavailability and bioequivalence from garlic supplements and garlic foods. Nutrients. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6073756/
Majewski, M. (2014). Allium sativum: Facts and myths regarding human health. National Institute of Public Health. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/24964572/
Murray, M., Pizzorno, J., & Pizzorno, L. (2005). The encyclopedia of healing foods. New York, NY: Atria Books.
Ota, A. & Ulrih, N.P. (2017). An overview of herbal products and secondary metabolites used for management of type two diabetes. Frontiers in Pharmacology. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5499308/
Pizzorno, J.E. & Murray, M.T. (2013). Textbook of natural medicine (4th ed.). St. Louis, MO: Elsevier Churchill Livingstone.
Ried, K. (2016). Garlic lowers blood pressure in hypertensive individuals, regulates serum cholesterol, and stimulates immunity: An updated meta-analysis and review. The Journal of Nutrition. Retrieved from: https://academic.oup.com/jn/article/146/2/389S/4584698
Soleimani, D., Paknahad, Z., Askari, G., Iraj, B., & Feizi, A. (2016). Effect of garlic powder consumption on body composition in patients with nonalcoholic fatty liver disease: A randomized, double-blind, placebo-controlled trial. Advanced Biomedical Research. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4763563/
West, H. (2016). How garlic fights colds and the flu. Healthline. Retrieved from: https://www.healthline.com/nutrition/garlic-fights-colds-and-flu