Garlic cloves add wonderful aroma and taste to a variety of dishes, but they are also packed with compounds and nutrients that can provide some health and medicinal benefits. Garlic has been used for culinary and medicinal purposes for more than 7,000 years in Asia, Africa and the Mediterranean region. Some of its benefits are still anecdotal, while others have been proved by research. Enjoy garlic on a regular basis, but don’t forget to pack the breath mints.
One of the strongest medicinal compounds in garlic is called allicin. Modern analysis of allicin shows that it’s an effective broad-spectrum antimicrobial, which means it destroys many pathogens such as bacteria, fungi, parasites and even some viruses. Unlike penicillin and other antibiotic drugs, allicin doesn’t harm the good bacteria in your intestines. Pathogenic microorganisms cannot evolve resistance against allicin, which means it always has the same impact and does not help breed resistant “super-bugs.” Allicin is also a good antioxidant that can destroy tissue-harming free radicals. Antioxidants are especially beneficial for protecting blood vessels from damage and reducing the risk of cardiovascular disease.
The other main medicinal compounds in garlic are called sulfides. Sulfides help with iron metabolism, which is beneficial to your blood due to hemoglobin production, and the absorption of selenium, an essential mineral. Some of garlic’s cardiovascular benefits are partly due to the action of hydrogen sulfide gas, which helps blood vessels expand in diameter and reduce blood pressure. Some sulfur compounds in garlic help to regulate the number of fat cells that get formed in your body, which can reduce blood cholesterol levels, while others act as good anti-inflammatories. The sulfur compounds are largely responsible for garlic’s pungent taste and odor.
Garlic is packed with manganese -- a very good source of vitamins B-6 and C -- and a selenium. Manganese helps the function of powerful antioxidants such as superoxide dismutase and helps boost “good” HDL cholesterol in your blood. Vitamin B-6 is important for nerve function, and it helps to prevent heart disease by lowering levels of circulating homocysteine, which damages blood vessel walls. Vitamin C is an excellent antioxidant that reduces levels of free radicals in your bloodstream, and it’s needed to make the elastic-like substance in your skin called collagen. Selenium is also a good antioxidant and works closely with vitamin E in your body.
Aged garlic tends to have better antioxidant effects, although eating fresh, chopped garlic will deliver more of the benefits related to allicin. Baking or microwaving garlic cloves destroys many nutrients and compounds. Instead, add chopped or sliced garlic to sauces, soups and other dishes just prior to serving them. Non-odorous garlic supplements are widely available if you want many of the benefits without the bad breath.
Some people are allergic to garlic, so use caution before eating raw garlic for the first time. Raw garlic can also irritate your skin and eyes, so wash your hands after preparing it. Garlic “thins” the blood, which means it reduces the ability for it to clot, so you shouldn't consume garlic if you are on blood-thinning medications such as coumarin. The anti-clotting property of garlic is one of the reasons why the American Dietetic Association recommends eating up to one garlic clove daily to reduce the risk of cardiovascular disease.
- Natural Standard Herb & Supplement Reference: Evidence-based Clinical Reviews; Catherine E. Ulbricht and Ethan M. Basch
- PDR for Herbal Medicines; PDR Medical Staff
- Principles and Practice of Phytotherapy: Modern Herbal Medicine; Simon Mills and Kerry Bone
- American Dietetic Association Complete Food and Nutrition Guide, 3rd Edition; American Dietetic Association
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.