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Can Onions Help Ward Off Flu?

The thought that the humble onion can battle respiratory infections might seem ludicrous. Here’s why the onion that gets you all teary-eyed can also be incredibly soothing and ease symptoms of flu, bronchitis, and allergic rhinitis.

That the humble onion can battle respiratory infections might seem a bit ludicrous. But with its powers as a natural antihistamine and the abundance of antioxidants in each bulb, the onion can be incredibly soothing and ease symptoms of flu, bronchitis, and allergic rhinitis. Here’s how this vegetable that gets you all teary-eyed works!

Traditional Flu Remedy

Onions have been used as far back as the time of the ancient Greeks to treat a range of flu-related problems. The onion was a standard flu and cold treatment among native Americans too. As the WHO explains, onions have been used in folk medicine, albeit without clinical study backing, as a treatment for bronchitis and fever, among other things.1 But now, these claims seem to hold water, with some researchers finding that certain compounds and antioxidants in onions may have a role to play in boosting your immunity, curing bronchitis, and easing symptoms that are typical of a bout of flu.

Onion As A Natural Antihistamine

Onions contain quercetin, one of nature’s most powerful antioxidants. Studies have found that quercetin can actually prevent the release of allergy-causing histamines in the body. This makes them natural antihistamines or anti-allergens, doing the work this class of medication would normally do. If you have frequents colds or coughs and these tend to be linked to your allergies, onions may prove especially useful.2 While there are other quercetin-containing foods like tea and apples, the amount of quercetin you are able to absorb from an onion is reported to be twice or thrice as much. What’s more, cooking onions at low heat doesn’t cause the loss of quercetin so you can tuck into warming stews, broths, and soups, knowing you’re getting all the goodness of a raw onion.3 One study found that quercetin had a significant inhibitory effect on histamine release in test subjects with perennial allergic rhinitis, resulting in a high degree of alleviation of their symptoms.4

Boosting Immunity: Polyphenols For Overall Health

Having good immunity and a strong constitution can go a long way in keeping bouts of flu at bay. Onions are rich in vitamins and minerals, including vitamin C, as well as flavonoids and polyphenol. 5 Because onions have high quantities of polyphenols which act as prebiotics, they help keep the balance of gut flora, ensuring enough good bacteria. This in turn helps with overall immunity. The antioxidant power of quercetin also kicks in to boost your immunity when you eat onions or onion-based remedies. A simple onion soup made from garlic, onions, and oregano with salt and water can be tremendously beneficial. According to one herbal guide, onion can even help loosen and clean out mucus built up in your system.6 Onions mixed with vinegar can also be taken to heal a sore throat.7

Antibacterial Effects Of Eating Onions

Onions also have antibacterial properties. The vegetable contains organosulfur compounds which are anti-inflammatory, anti-microbial, and anti-allergic. This is because of the presence of sulfur compounds that are the primary antimicrobial agents in the onion. Besides this, some researchers have found that onions also have quercetin oxidation products that are effective against multidrug-resistant S. aureus (MRSA) bacteria.8

Anti-asthmatic Effects

Researchers have found that the thiosulfinates and cepaenes in onions may have a role to play in mediating reactions that bring on bronchial restriction. This constriction of the airways is not unlike what you might experience when you have asthma, indicating the possibilities of treatment using onions.9

Some studies have found that the quercetin in onion has an effect similar to that of drugs used to treat asthma brought on by allergic conditions. Acting as a bronchodilator, it is able to cut down the hyperactivity of the airways, typical of allergic asthma.10

However, because there have been instances of asthma being triggered by onions among people allergic to the vegetable, you should be sure you have no such allergies before you consume them.

Homeopathic Use Of Onions

In homeopathy, onion or Allium cepa is a common remedy for specific types of colds. It has been indicated for use in people who experience incessant sneezing accompanied by teary eyes. So how do you spot the kind of flu or cold that benefits from onion-based remedies? According to homeopathic medicine, this kind of cold causes an acrid nasal discharge that makes the nose raw and sore. Your eyes may be quite sensitive to light and feel itchy and red. In addition, if you have a water discharge from the eyes, not unlike what happens when you chop an onion, then you could do with a dose of Allium cepa. If you have a sore throat, the remedy can help as well. It can also be used to treat bronchitis in elderly patients.11

References   [ + ]

1. WHO Monographs on Selected Medicinal Plants – Volume 1, WHO.
2. Quercetin, University of Maryland Medical Center.
3. Mateljan, George. The World’s Healthiest Foods: Essential Guide for the Healthiest Way of Eating. George Mateljan Foundation, 2007.
4. Otsuka, Hirokuni, Makoto Inaba, Terumichi Fujikura, and Mayumi Kunitomo. “Histochemical and functional characteristics of metachromatic cells in the nasal epithelium in allergic rhinitis: studies of nasal scrapings and their dispersed cells.” Journal of allergy and clinical immunology 96, no. 4 (1995): 528-536.
5. National Nutrient Database for Standard Reference Release 28, USDA.
6. Corzo-Martínez, Marta, Nieves Corzo, and Mar Villamiel. “Biological properties of onions and garlic.” Trends in food science & technology 18, no. 12 (2007): 609-625.
7. Rabinowitch, Haim D., and J. L. Brewster. Onions and Allied Crops: Biochemistry food science minor crops. Vol. 3. CRC Press, 1989.
8. Ramos, Freddy A., Yoshihisa Takaishi, Miki Shirotori, Yousuke Kawaguchi, Koichiro Tsuchiya, Hirofumi Shibata, Tomihiko Higuti, Tetsuo Tadokoro, and Minoru Takeuchi. “Antibacterial and antioxidant activities of quercetin oxidation products from yellow onion (Allium cepa) skin.” Journal of agricultural and food chemistry 54, no. 10 (2006): 3551-3557.
9. Wagner, H., W. Dorsch, Th Bayer, W. Breu, and F. Willer. “Antiasthmatic effects of onions: inhibition of 5-lipoxygenase and cyclooxygenase in vitro by thiosulfinates and “Cepaenes”.” Prostaglandins, leukotrienes and Essential fatty acids 39, no. 1 (1990): 59-62.
10. Joskova, M., S. Franova, and V. Sadlonova. “Acute bronchodilator effect of quercetin in experimental allergic asthma.” Bratisl Lek Listy 112, no. 1 (2011): 9-12.
11. Healing the interconnected anatomy of ENT, British Homeopathic Association.

Disclaimer: The content is purely informative and educational in nature and should not be construed as medical advice. Please use the content only in consultation with an appropriate certified medical or healthcare professional.