The Surprising Benefits Of Onion Juice For Your Health

Archaeological evidence shows that we have been eating onions since at least 5000 BC. However, it seems it was the Ancient Greeks who first realized their health benefits.

By the Middle Ages onions were considered so valuable that they were often used for paying rent or given as a gift.

Despite this and despite the fact that juicing has taken the world by storm; onion juice is rarely on the menu.

People are juicing for general health, weight loss and detoxing but few are drinking onion juice.

Onions are a powerhouse of nutrition and deserve to be added to the juice menus around the globe.

Choose organic onions, not the hybrid varieties sold in many stores which are deliberately cultivated to be sweet.

Below we take a look at the many benefits to adding onion juice to your daily diet.

Benefits of Onion Juice​

Nutritional Value of Onion Juice

Onions are very healthy. They are excellent source of phytochemicals, flavonoids, sulphuric compounds and also vitamin C. These health-promoting components act as anti-carcinogenic, antioxidants and anti-inflammatory agents which makes the onion an underestimated source of health.

Anti-inflammatory, Antibacterial, Antiviral, Anti-allergenic

Cornell University food science faculty published results of a study on the health benefits of onions in the Journal of Agricultural and Food Chemistry. Associate professor, Rui Hai Liu, MD, PhD, said, “Our study clearly shows that the health benefits of onions and shallots have potent…. antioxidant activity and protective effect.” Liu continued, “Onions are one of the richest sources of flavonoids in the human diet. Flavonoids are not only anti-cancer but also are known to be antibacterial, antiviral, anti-allergenic and anti-inflammatory.

The research also showed that the amount of quercetin was greater in yellow and red onions and shallots.


The antibacterial and anti-inflammatory properties in onion juice aid digestion. The juice also helps with constipation and flatulence.

The results of a study investigating the effects of red onion juice on stomach related problems were published in the November 2009 issue of the journal “Toxicology”.

The results showed that onion juice relaxed stomach muscles which were tense due to stress or food related problems.

The National Onion Association has conducted studies which show that the phytochemicals in onions kill off the free radicals which will, in turn, reduce the advent of gastric ulcers.

Another property of the onion, inulin, feeds the good bacteria in the gut and, as the gut contains 80% of our immune system, that can only be a good thing. Inulin works as a natural regulator, keeping the good bacteria at optimal levels.

Respiratory Disorder and Colds

The anti-inflammatory properties of onion juice make it the perfect relief from bronchitis and respiratory disorders.

The oil in onion juice helps prevent mucus from forming and also acts as an expectorant, helping the body to rid itself of excess mucus.

Urinary Tract Infections

Drinking onion juice gives relief from the burning sensation experienced with urinary tract infections. It is also a natural diuretic, so it helps to keep the bladder empty.


Onions contain quercetin which is a strong antioxidant and natural antihistamine that helps with allergic reactions and inflammatory conditions such as asthma. The results of research in the July-December 2006 “Journal of Biological Regulators and Homeostatic Agents” showed that quercetin inhibits histamine and thus lessens or prevents allergic reactions.


Onion juice has been shown to stimulate hair growth when used topically. Studies have shown that using onion juice on the scalp for eight weeks increases the growth of hair significantly.

The sulfur content of the onion acts as a natural antibacterial and antifungal agent and clears away debris from the hair follicles, thus encouraging growth.


The National Osteoporosis Foundation in the US states that 54 million people over the age of 50 have low bone density or osteoporosis.

Onions contain a glutamyl peptide which helps the leaching of minerals from the bones.

They also contain silicon which is good for bone health.

The Medical University of South Carolina’s research on the effects of consuming onions on peri- and post-menopausal women strongly suggests that including onions, either cooked, raw or juice, in a diet will increase bone density.


Onion juice increases blood circulation which helps prevent toxins from remaining in the blood stream.

The quercetin, vitamin C, A and E in onion juice are all great antioxidants which nourish the skin and help prevent UV damage and premature aging.

Onion juice can also be used topically on the skin and is said to even out skin tone, remove freckles and lighten the colour of moles and liver spots.

Eyes – Cataracts

It is estimated that over 50% of Americans have cataracts in at least one eye by the time they reach 80. Research which was published in the May/June 2009 issue of the “Indian Journal of Ophthalmology” concludes that onion juice prevents the formation of cataracts in certain animals. More research is being carried out to see if the same effect is found in humans.

Glucose Levels

A study was conducted in 2010 to investigate the possible positive effects of onions on hypoglycemic levels in patients with type-1 and type-2 diabetes. 

The results of this study show that consuming onion juice and eating onions has a positive effect on glucose levels in patients with diabetes.

Onions contain chromium which is a natural glucose regulator and something people take when trying to quit sugar to stop the cravings. Onions also contain allyl propyl disulphide which is instrumental in assuring the body maintains proper sugar levels.

Cardiovascular Health and Cholesterol

Onions contain Vitamin B, sulfur and chromium, all of which are known to lower cholesterol build up.

The results of a study published in the British Journal of Nutrition in 2009 showed that the quercetin in onions reduced LDL cholesterol and systolic blood pressure in people who were carrying excess weight. This is obviously beneficial to cardiovascular health.

Onions and their juice are natural anti-coagulants which helps in the prevention of the forming of blood clots.

Research is being conducted at the University of Maryland Medical Centre to ascertain whether the quercetin content in onion juice stops or slows down the plaque build-up in the arteries. If it does, then that would be another positive step in heart disease prevention.


Onion juice is rich in iron, copper, sulfur and vitamin C. It stimulates blood circulation and improves haemoglobin levels, so helping to prevent and cure anemia.

Fighting Cancer

The July 2011 issue of “Gastroenterology” strongly recommends eating a diet high in onions to help prevent stomach cancer. Red onions are particularly recommended for their high quercetin and sulfur content. The sulfides in onions are natural anti-carcinogenics.

Studies in Italy and Switzerland have confirmed that drinking onion juice or consuming onions daily reduces the possibilities of cancer of the mouth, esophagus,ovaries, larynx and kidneys.

The study by Cornell University food scientists on the effects of various types of onions and shallots on cancer cells has produced interesting results. “Our study of 10 onion varieties and shallots clearly shows that onions and shallots have potent antioxidant and anti proliferation activities and that the more total phenolic and flavonoid content an onion has the stronger its antioxidant activity and protective effect,” says Dr. Liu, associate professor at Cornell. The results showed that different types of onions and/or shallots were beneficial to different types of cancer.

“Onions are one of the richest sources of flavonoids in the human diet,” Liu said. “And flavonoid consumption has been associated with a reduced risk of cancer, heart disease and diabetes. Flavonoids are not only anti-cancer but also are known to be anti-bacterial, anti-viral, anti-allergenic and anti-inflammatory.”

How to Drink Onion Juice

Obviously, onion juice is not the most palatable juice. One medium onion produces around a shot and this is the perfect daily dose.

The ideal time to drink it is first thing in the morning and then refrain from eating for at least one hour. If you find it impossible to drink, then try having a little honey in hot water before and after the shot.

When preparing the onion, peel off as little as possible as many of its healthy components are concentrated in the outer layers of the onion.

The best way to juice an onion is to put it through a juicer but, if you don’t have one, chop it into small pieces and squeeze out the juice. Strain the juice well to remove all the onion bits before drinking.

The Last Word

Onion juice may not be exceptionally palatable but, with its myriad of health benefits, it is certainly worth persevering with.

Some health practitioners believe it is not only curative and preventative, it also helps with memory loss and aids a good night’s sleep. 

It is also excellent for oral health, fighting gum disease and infections. Its health-giving properties are endless.