Red onions, also known as purple onions, come with purplish red skin and white flesh tinged with red. They are medium to large in size with a mild to sweet flavour and are often eaten raw, grilled or lightly cooked with other foods, or added as color to salads. Their redness tends to disappear when cooked. Red onions belong to the lily family. Though we use them as spices to our food, red onions have a great deal of health benefits besides adding taste to the food.

We shall be taking a look at the following in this article;

  • Health benefits of red onions,
  • Risks associated with red onions and
  • The nutritional facts about onions.

Red onions have lots of health benefits which helps the body to function optimally. Listed below are the health benefits derived from consuming them;

  1. Improved Immunity

The photochemical in onions aid the function of vitamin C hence help to improve the body’s ability to fight infections. This is important in boosting the body’s immunity.

  1. Blood sugar control

Onions play a very important role in blood sugar regulation owing to the fact that they contain a mineral component known as chromium.

  1. 3. Fighting Inflammation

Red onions have since time immemorial been used to treat inflammations and infections as well.

  1. Healthy heart

Raw slices of red onions are actually good for your heart. This is because they encourage production of High Density Lipoprotein (HDL) which minimizes risk of heart diseases like heart attack and stroke. Low Density Lipoprotein (LDL) on the other hand leads to heart problems due to cholesterol levels in the arteries which triggers the so called Cardiovascular Diseases (CVDs).

  1. Cancer prevention

Red onions are important in the war against cancer. This is because they contain a powerful chemical known as quercetin. Quercetin belongs to a group of plant pigments known as flavonoids. It is responsible for giving onions their red color. Quercetin’s role is to inhibit the growth of cancer cells ranging from breast, colon, and prostate to ovarian cancer. It has been shown through research that intake of quercitin lowers risk of lung cancer.

  1. Pain Relief

Unknown to many people, red onions are useful in relieving pain and in particular, pain caused by stinging insects which leaves a burning sensation. If you have been stung by a bee, apply red onion juice on the affected area and you will experience immediate relief from the burning sensation.

  1. Prevents Gastric Ulcers

The fiber in onions promotes good digestion and helps keep you regular. Additionally, onions contain a special type of soluble fiber called oligofructose, which promotes good bacteria growth in your intestines. One 2005 study in Clinical Gastroenterology and Hepatology found that oligofructose may help prevent and treat types of diarrhea. The phytochemicals in onions that scavenge free radicals may also reduce your risk of developing gastric ulcers.

  1. Bone density in older women

A 2009 study in the journal Menopause found that daily consumption of onions improves bone density in women who are going through or have finished menopause. Women who ate onions frequently had a 20 percent lower risk of hip fracture than those who never ate onions.

  1. 9. Regulating blood sugar

The chromium in onions plays a vital role in regulating blood sugar level. The sulfur in onions also helps lower blood sugar by triggering increased insulin production. People with Type 1 and Type 2 diabetes who ate red onions showed lower glucose levels for up to four hours.

Health risks associated with onions.

While not especially serious, eating onions can cause problems for some people. The carbohydrates in onions may cause gas and bloating. According to a 1990 study in the American Journal of Gastroenterology, Onions, especially if consumed raw, can worsen heartburn in people who suffer from chronic heartburn or gastric reflux disease.

Eating a large amount of green onions or rapidly increasing your consumption of green onions may interfere with blood thinning drugs, according to the University of Georgia. Green onions contain a high amount of vitamin K, which can decrease blood thinner functioning.

It is also possible to have food intolerance or an allergy to onions, but cases are rare, according to an article in the Journal of Allergy and Clinical Immunology. People with onion allergies may experience red, itchy eyes and rashes if an onion comes into contact with the skin. People with intolerance to onions may experience nausea, vomiting and other gastric discomfort.

Lastly, Jarzabkowski encouraged people to make sure their onions are fresh. “Onions keep for a long time,” she said, “but they still spoil.”

Onion facts

Slicing onions makes you cry because when you cut into it, the onion produces a sulfur-based gas. The gas reacts with the water in your eyes and forms sulfuric acid. To rid your eyes of this fiery irritant, your tear ducts work overtime. For no more (or fewer) tears, try moving your face farther away from the onion so the gas disperses before reaching your eyes.

Another suggestion for reducing tears is to first chill the onions for 30 minutes. Then, cut off the top and peel the outer layers leaving the root end intact.

Onions range in size from less than 1 inch to more than 4.5 inches in diameter. The most common sizes sold in U.S. markets are 2 to 3.75 inches.

The leading onion production countries are China, India, United States, Turkey and Pakistan.

The average American eats 20 pounds (9 kg) of onions per year.

To avoid “onion breath,” eat a sprig of parsley, or rinse your mouth with equal parts lemon juice and water, or chew a citrus peel.


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El-Aasr M, Fujiwara Y, Takeya M et al. Onionin A from Allium cepa inhibits macrophage activation. J Nat Prod. 2010 Jul 23;73(7):1306-8. 2010.

Azuma K, Minami Y, Ippoushi K et al. Lowering effects of onion intake on oxidative stress biomarkers in streptozotocin-induced diabetic rats. J Clin Biochem Nutr. 2007 Mar;40(2):131-40. 2007.

Borjihan B, Ogita A, Fujita KI et al. The Cyclic Organosulfur Compound Zwiebelane A from Onion (Allium cepa) Functions as an Enhancer of Polymyxin B in Fungal Vacuole Disruption. Planta Med. 2010 May 19. [Epub ahead of print]. 2010.

Brat P, George S, Bellamy A, et al. Daily Polyphenol Intake in France from Fruit and Vegetables. J. Nutr. 136:2368-2373, September 2006. 2006.

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