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Health Benefits of Onion, Uses And Its Side Effects

Last Updated: Sep 03, 2020

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Onion is one of the common vegetables used in hundreds of dishes all over the world to enhance the taste. Eating raw onion daily offers lots of health benefits. Vitamin C and other nutrients in onion help to check cancer and also enhance skin and hair. The blood sugar levels are largely controlled by onion extracts and it also boosts immunity, sex drive and anemia control.


Onions are vegetables, which have the scientific classification of Allium cepa. They are rich in antioxidant compounds that are very effective in neutralizing the free radicals present in the human body. They have been used for decades by human beings for medicinal purposes.

Nutritional Value of Onion

Onions have many valuable medicinal applications because it acts as a rich source of nutrients, vitamins, minerals, and organic compounds. These include the presence of sulfuric compounds and quercetin which are essential for health.

Onion also contain mineral components such as calcium, magnesium, sodium, potassium, selenium, and phosphorus and they are a good source of vitamin C, vitamin B6, and dietary fiber.

Nutritional facts Per 100 Grams

0.1 g
Total Fat
4 mg
146 mg
9 g
Total Carbohydrate
1.1 g

Vitamins and Minerals

12 %
Vitamin C
1 %
5 %
Vitamin B-6
2 %

Health Benefits of Onion

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After getting onion nutrition facts, let check amazing Health Benefits of eating onions, you can onion in a different way, you can use raw onion in cooking for hundreds of dishes. Onion juice is also used for hair growth and skin care. According to the season, you find various onions such as red onion, green onion, white onion, etc. Onion offers medicinal properties and is used to treat mouth sores, headaches, and heart problems.

Onion Fight Against Cancer

Red onions are the most effective in destroying breast and colon cancer cells. Onions have a powerful compound called quercetin that plays a significant role in preventing cancer.

Onion Lower Blood Sugar Levels

One of the sulfur compounds present in onions (S-methylcysteine) and quercetin can have beneficial effects on controlling the blood sugar level in the body. Chromium, also present in this root vegetable, may help regulate blood sugar.

Onion Prevent Inflammation And Other Allergies

Quercetin (and other flavonoids) in onions helps in preventing inflammation. Onion also helps the treatment of allergies by preventing the cells from releasing histamine.Antihistamine properties of quercetin can also aid in reducing nasal congestion. The antibiotic effects of onion accelerate wound healing.

Onion Promote Respiratory Health

Patients with respiratory issues like asthma and allergic rhinitis can benefit from onion extracts. The prebiotics present in onion can help removing nasal congesion and thus aiding peaceful sleep.

Onion Juice Benefits for Eyes Health

The sulfur in onions improves the health of the lens of the eye thus aiding in vision. It stimulates the greater production of a protein named glutathione, which acts as an antioxidant and reduces risk of glaucoma, macular degeneration, and cataracts.

The selenium in onions supports the vitamin E in the eye (which protects the cells in the eye).Onion extracts can also aid in preventing the development of corneal haze and onion juice can also be used as eye-drops.

Onion Good for Oral Thrush

Onions contain a rich source of thiosulfinates and thiosulfonates (the sulfur compounds) that help scale down bacteria that cause tooth decay.The vegetable is also enriched in vitamin C that keeps the teeth healthy.Onions can relieve tooth pain.

Onion Juice for Hair Fall & Hair Regrowth

Rich in antibacterial and antifungal properties, onions help to nurture hair and proliferates its growth. The rich sulfur content and antioxidants prevent thinning and breakage and premature greying. They fight dandruff and assist in blood circulation that helps in hair growth.

Onion Benefits for Brain Health

Antioxidant rich onions bind with the harmful toxins in the brain and flush them out of the body.The extracts of onions have been found to maintain the hippocampus.

Another sulfur-compound in onions, named di-n-propyl trisulfide, improves memory impairment and lower down age-related memory loss. Onions are also believed to treat dizziness, epilepsy, and vertigo.

Uses of Onion

Onions are crucial for other benefts also, like treatment of fever, easing menopause symptoms and reducing oxidative stress. The phytochemicals in onions along with their vitamin C help improve immunity. Raw onion lowers the production of bad cholesterol (LDL). Onion juice also provides immediate relief from the pain and burning sensation. It is also used for skin problems.


Side-Effects and Allergies of Onion

Onion might slow blood clotting and might increase the risk of bleeding when taken as a medicine. Onion might lower blood sugar. Overconsumption of onions for diabetic patients can be harmful. Onion might increase the risk for bleeding or interfere with blood sugar control during and after surgical procedures.

Cultivation of Onion

It is believed that onions originated in Asia. Although the exact location is not known, it is assumed that onions are native to West Pakistan and Iran. The onion plant has a fan of hollow, bluish-green leaves and its bulb at the base of the plant begins to swell on reaching a certain day-length.

The bulbs are composed of shortened, compressed, underground stems surrounded by fleshy modified scale (leaves) that envelop a central bud at the tip of the stem. In the autumn (or in the spring), the foliage dies down and the outer layers of the bulb become dry and brittle. The crop is then harvested and dried and the onions are ready for use or storage.


  • Upadhyay RK. Nutraceutical, pharmaceutical and therapeutic uses of Allium cepa: A review. International Journal of Green Pharmacy (IJGP). 2016 Mar 21;10(1). [Cited 26 June 2019].
  • Bora KS, Anupam S. Phytoconstituents and therapeutic potential of Allium cepa Linn.-a review. Pharmacognosy Reviews. 2009;3(5):159-69. [Cited 26 June 2019]. Available from:
  • Sharquie KE, Al‐Obaidi HK. Onion juice (Allium cepa L.), a new topical treatment for alopecia areata. The Journal of dermatology. 2002 Jun;29(6):343-6. [Cited 26 June 2019]. Available from:

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    Written ByDrx Hina FirdousPhD (Pharmacology) Pursuing, M.Pharma (Pharmacology), B.Pharma - Certificate in Nutrition and Child CarePharmacology
    Reviewed By
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    Reviewed ByDt. Ms. Shilpa MarwahB.Sc (Home Science), Post Graduation Diploma in Dietetics and Public Health NutritionDietitian/Nutritionist

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