When we cut onions, the sulfur compounds that give them their characteristic scent escape into the air as vapors. These vapors cause our eyes to become itchy and watery, a condition known as lachrymatory. Scientists are working to find ways to eliminate this problem through genetic engineering. However, for now, the best way to avoid the tearing when cutting onions is to hold them in water for some time before you try to cut them.
Onions contain quercetin, a flavonoid that helps lower high blood pressure. A small 2015 study found that people who ate an average of 162 mg of quercetin from onions daily had lower systolic blood pressure than those who did not.
The sulfur in onions also has anti-inflammatory properties. It can help treat a sore throat, reduce the symptoms of a cold and prevent asthma attacks. It can even help heal wounds faster. The glucosinolates in onions also help protect against heart disease, as well as lower the risk of cataracts and eye diseases.
Studies have shown that Allicin, a compound found in onions and garlic, can inhibit the growth of some cancer cells, as well as prevent them from spreading. It is thought to work by blocking the activity of certain enzymes in the cell, thereby inhibiting their ability to spread and multiply.
Allicin has powerful antibacterial properties, as well. It can help to kill harmful bacteria that may be causing infection in the colon, as well as reduce symptoms of IBS and other digestive conditions. The soluble fiber in onions, called inulin, is also beneficial for your digestive system, as it feeds the good bacteria in your gut and cuts down on gastric ulcers.
Another important benefit of onions is that they can help to prevent and fight the common cold, as well as treat ear infections. The antiviral, antifungal and antibacterial properties of Allicin are believed to be responsible for this effect. A spoonful of onion-honey syrup can ease the symptoms of a cough and soothe sore throats, while also soothing the stomach and fighting viral infections.
Onions can also be used to get rid of head lice naturally. Grind 4 to 5 onions to make a paste, and apply it to your scalp. Leave it on for 2 hours, then shampoo your hair. You can then use a nit comb to remove the lice and eggs. Repeat this treatment for 3 days.
If you suffer from a dry, flaky scalp, the sulfates in onions can help to restore its health. To make an effective onion shampoo, simply mix a cup of milk and a tablespoon of honey with 1 cup of chopped onions. The heat of the mixture will melt the onion, and then you can strain out the mixture and pour it into a bottle for storage. Use this shampoo regularly to keep your scalp healthy and free of lice and other fungi. You can also try adding a pinch of turmeric to the shampoo to enhance its efficacy.