They’re aromatic, pungent and tasty, but the benefits of cooking with onion and garlic may go far beyond their incredible flavor profiles. Both packed with nutrients and powerful antioxidants, these gems have been staples in folk medicine for thousands of years, and many of those remedies persist across the world today. Now, even modern medicine is finally backing some of their health claims.
Studies have shown onions and garlic can improve cardiovascular health by lowering blood pressure and thinning the blood — but that's not all they can do. Research is being conducted on the possibility of using them in place of antibiotics, and they may even reduce cancer risks.
Onions and garlic are packed with nutrients, including two antioxidants known as flavonoids. One of them is anthocyanin, which is responsible for those gorgeous purples and reds you can find on some bulbs. The other is quercetin, which causes the formation of yellows and browns on less colorful varieties. Another compound, allicin, which is activated when the bulb is cut or crushed, is also believed to have anticancer properties.
The antioxidants found in onions and garlic may help protect against cardiovascular disease and cancer. Some studies show they can reduce blood pressure and thin the blood, which reduces the risk of atherosclerosis. Anthocyanin, quercetin, allicin and other potentially medicinal compounds help give onions and garlic their unique, pungent bite.
Onions and garlic may have mild to moderate antibiotic properties. Studies using raw garlic juice have shown it to be an effective treatment against Helicobacter pylori (H. pylori), the bacterium responsible for many stomach ulcers. Garlic even seems to be effective against some antibiotic-resistant strains. In addition, it prevents the bacteria from producing toxins, some of which are believed to lead to H. pylori-related stomach cancer tumors.
In another study, researchers used different dilutions of garlic, onion and ginger extracts against several bacteria that included strains of salmonella and staph. The ginger extract failed to eradicate any of the bacteria, but a 2% solution of onion extract was able to kill most. Even more impressive, all concentrations of garlic extract were effective against all the bacteria tested. It’s important to note these tests took place in Petri dishes, so much more testing is required to determine if these extracts are as effective when ingested.
Heat destroys many of the active compounds in onions and garlic, so try to eat your onions raw, like in salads or pickled with cucumbers and vinegar. You can get the most out of your garlic by crushing it and letting it sit for about 10 minutes before cooking it. Freeze-dried powders can be more convenient for cooking, and they pack nearly as many benefits as their fresh counterparts.
Despite their amazing properties, onions and garlic might cause some people more harm than good. For example, people with autoimmune diseases might need to avoid immune-boosting foods since their immune systems may already be in overdrive. Some people with asthma may find eating garlic can trigger attacks.
Onion and garlic are two of the world’s most widely used herbs with good reason, and the flavors they bring are only added benefits. Bad breath aside, they’re a healthy addition to almost any diet, so use them liberally and often. The benefits may end up being even greater than you anticipated.