Introduction

Onions are part of the allium family of herbs and vegetables that also includes garlic, chives, leeks, and scallions. Allium vegetables have been cultivated for centuries. Initially onions were used for their pungent flavor during cooking but later their medicinal properties were realized and their use has become widespread.

Onions are available in many sizes, colors, shapes and flavors. The most common types of onions are yellow, red and white. Even the flavors of onions vary from spicy, pungent to sweet depending on the season they are grown.

Each year more than 100 billions pounds of onion are harvested and consumed globally.

What do onions contain?

Onions are not a high caloric food but instead are rich in nutrients like minerals, vitamins, and antioxidants like the bioflavanoid quercetin. The amount of calories in one onion is about 64 calories and consists of a few grams of carbohydrate, fiber and protein. Onions also contain trace amounts of sulfur, phosphorus, iron, folate, potassium, and calcium.

What are the health benefits of onions?

Over the years it has become clear that onions have several health benefits which include the following:

Cancer prevention: There are many anecdotal reports suggesting that onions can prevent cancer of the stomach and colon. This benefit has been linked to the presence of organosulfur in the onion. It is believed that the sulfur prevents tumor growth and inhibits production of free radicals. Onions are also a rich source of vitamin C that can scavenge free radicals and decrease the risk of cancer. Plus, the fiber content of onions may also be responsible for the decrease in colon cancer. Onions have also been reported to prevent prostate, esophageal and stomach cancer.

Sleep improvement: Some people who take onions in the evening have been known to sleep well. This is because onions have folate which prevents the homocysteine from interfering with the sleep wake cycle.

Skin Improvement: Regular intake of onions has also been shown to improve the skin tone and texture. This is because of the tightening effect on the collagen, located below the skin.

Digestive Support: Onions have also been known to reduce stomach acidity and relieve constipation.

Cold and Flu Prevention: there is ample evidence indicating that regular consumption of onions can prevent and/or reduce the intensity of the common cold. In addition, onions also prevent stomach upset caused by bacteria.

Wart Resolution: There are anecdotal reports that rubbing the fresh onion on the wart speeds up its resolution.

How should i eat onions?

Onions can be eaten in several ways. The most common is boiled, fried, grilled or caramelized. It can even be used fresh in salads, dips or sauces.

There is also dried onion available which has minimal odor and can be used as a garnish.

Perhaps the best way to enjoy onions is to use it as a flavoring agent during cooking. Only a little bit is required and this also avoids the pungent smell.

What are side effects of onions?

In general, onions are very safe. In rare cases an allergy may develop. The most common negative aesthetic effect is bad breath. Thus, after eating onions, it is best to brush and rinse the mouth. The breath can instantly be improved by eating an apple or a few sprigs of parsley. After chopping onions, wash hands in salty water, followed by soap.

How to buy onions

Always buy onions that are firm and have dry shiny skin. Store onions at room temperature and keep them away from bright light. The yellow onions tend to have a longer shelf life compared to the other onions. Always keep onions away from fruit and potatoes as the gases released can speed up ripening. Never freeze onions as they lose their flavor and health benefits.

Final Note

Because onions contain very few calories they should not be relied upon as the sole source of food. In addition, it is important to understand that onions are not a substitute for prescription medications but only a supplementary benefit.

References

Antitumor Allium Sulfides. Nohara T, Fujiwara Y, El-Aasr M, Ikeda T, Ono M, Nakano D, Kinjo J. Chem Pharm Bull (Tokyo). 2017;65(3):209-217. Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid.

Anand David AV, Arulmoli R, Parasuraman S. Pharmacogn Rev. 2016 Jul-Dec;10(20):84-89. Plants of the genus Allium as antibacterial agents: From tradition to pharmacy.

Sharifi-Rad J, Mnayer D, Tabanelli G, Stojanović-Radić ZZ, Sharifi-Rad M, Yousaf Z, Vallone L, Setzer WN, Iriti M. Cell Mol Biol (Noisy-le-grand). 2016 Aug 29;62(9):57-68. Cardiovascular Disease: A Target for the Pharmacological Effects of Quercetin.

Gormaz JG, Quintremil S, Rodrigo R. Curr Top Med Chem. 2015;15(17):1735-42. Onions a Superfood???

Dorant, Van Den Brandt, Goldbohm, Sturmans, Gastroenterology, “Consumption of Onions and a Reduced Risk of Stomach Carcinoma,” 1996.

2 http://www.sciencedirect.com/science/article/pii/S0278691503003508, Antimutagenic, antioxidant and free radical scavenging activity of ethyl acetate extracts from white, yellow and red onions, Aug. 2012

Mercola, What’s new and beneficial about onions, April 2014 http://articles.mercola.com/sites/articles/archive/2014/04/12/onion-health-benefits.aspx

Onions, World’s Healthiest Foods, http://www.whfoods.com/genpage.php?tname=foodspice&dbid=45

Anya V, The Magic Onion: Things You Didn’t Know Onions Could Do, Living Traditionally, http://livingtraditionally.com/the-magic-onion-things-you-didnt-know-onions-could-do/, November 2015.

Onions, Wikipedia, https://en.wikipedia.org/wiki/Onion

Ware, Megan, RDN, LD, Onions: Health Benefits, Nutritional Information, Medical News Today, September 2015