20 Surprising Benefits of Onions
Onions are cultivated and consumed across the world. They are usually served cooked. They can also be eaten raw and are used in pickles and chutneys. The onion has a strong taste and a sharp, pungent flavour. Though it is a temperate crop, it can be grown under a wide range of climatic conditions (temperate, tropical, and subtropical).
The bulb onion, as we discussed, is nothing but the short stem with fleshy leaves. It acts as a food reserve that helps the plant survive during harsh weather conditions.
That’s quite intriguing, isn’t it? But onions have a history too.
The ancient origin of onions spans the western and eastern parts of Asia. There are numerous species of onions found the world over, which basically means they were cultivated across the world probably at the same time. Records suggest that onions started to be used in China way back in 5000 BC – more so because of the bulb’s durability to transport and store. Ancient Egyptians were known to revere the vegetable, considering its spherical shape and concentric rings a symbol of eternal life. In fact, onions were also used in ancient Egyptian burials. The medical documents of Charaka Samhita (way back in the 6thcentury BC) mention onion as a medicinal plant. Even a Greek physician from the 1stcentury AD (Discords) documented the vegetable’s medicinal uses. And it was the first European settlers who had taken onions to North America. That’s a bit of the history. But did you know that there are different types of onions?
What Are The Different Types Of Onions?
Onion is so widely used that any culinary dish from almost any part of the earth has the vegetable added to it. No doubt there are several types of onions – but here, we talk about the most common ones.
Yellow onions –They have ivory white flesh that is surrounded by heavy brown skin. They have a strong and sulphur-like aroma.
Sweet onions –They have a lighter, less-opaque skin that surrounds a larger and slightly fatter body of the vegetable.
White onions –They have a papery white skin, and they are milder and sweeter than their yellow counterparts.
Red onions –They are mild and sweet enough to be eaten raw. The exterior skin and flesh are a deep magenta.
Shallots –They are smaller and brown-skinned and have purple flesh.
Green onions –They are the immature onions that haven’t yet formed a bulb.
Leeks –They are shaped like overgrown scallions (the long-necked onion with a small bulb) and are usually used in sauces and soups.
But why talk so much about onions? What is so wonderful about them? And the big question –
Whether it is raw onions or cooked onions, they are loaded with benefits. And you can eat them whenever you want – day or night. The vegetables are an excellent source of vitamins C and B6, folate, iron, and potassium. Onions are also rich in manganese that offers protection against cold and flu. Allium and allyl disulphide, two phytochemicals in onions, are converted into allicin post ingestion. Allicin, as per certain studies, has properties to fight cancer and diabetes (1). It can also reduce the stiffness of blood vessels and lower blood pressure levels. Even the other onion types like chives, leeks, and shallots have similar benefits. Onions also contain quercetin, another antioxidant that fights inflammation. More interestingly, cooking onions in soup doesn’t diminish their quercetin value but simply transfers the antioxidant from the vegetable to the soup broth.
And not just the vegetable, even the essential oil from onions has benefits. The oil has antiseptic and antibacterial properties. Onions, when combined with garlic, could have greater benefits. The two, together, are known to be effective antidepressants, painkillers, anticoagulants, and anti-inflammatory. And though onions may not induce weight loss directly, substituting them for high-calorie foods can make some contribution.
Some people may ask Is It Better To Eat Onions Raw Or Cooked?
Whether raw or cooked – onions are super healthy. However, raw onions have higher levels of organic sulphur compounds that offer numerous benefits. One study has found that the outer layers of onion flesh have the highest concentrations of flavonoids – hence, ensure you remove as little of this part as possible while peeling the vegetable (2).
Boiled onions also have benefits. They serve as a good source of fibre and copper. Fibber helps keep digestive issues at bay while copper aids brain communication. Even pickled onions have most of the benefits onions provide. One point to be noted about pickled onions is – most brands contain additives and could be harmful.
All of what we spoke about, all of these benefits, are because of the nutrients present in onions. Which is what we will look at now.
One small onion contains about 28 calories and 7 grams of carbs. Onions are also rich in vitamins A, B6, B-complex, and C, as well as iron, folate, and potassium. They are excellent sources of sulphuric compounds, flavonoids, phytochemicals, and polyphenols.
Healthy Benefits of Onions
- Fight Cancer
As per a study conducted by the University of Guelph, red onions are the most effective in destroying breast and colon cancer cells these onions have high levels of quercetin and anthocyanin – two compounds that contribute to this characteristic. Onions activate the pathways that provoke the cancer cells to kill themselves. They make the environment unfavourable for cancer cells to communicate, and this inhibits their growth. It was also found that people with the highest consumption of onions had the lowest cancer rates. As a preventative measure, you can have your burgers garnished with red onions.
- Improve Heart Health
The flavonoids in red onions can contribute to heart health. Onions are also rich in organic sulphurs, which can help prevent heart disease. According to one Argentine study, intake of the organic sulphur compounds found in onions can cut the risk of cardiovascular disease. Onions contain thiosulfinates that act as natural blood thinners and reduce the risk of heart attack and stroke.
The quercetin in onions also has the potential to fight heart disease. It offers both antioxidant and anti-inflammatory properties that promote heart health. Onions are also a part of the French Paradox – they are an important part of French cuisine and are thought to be responsible for the low incidences of heart disease among the French despite their high-calorie diet. Onions can also improve cholesterol levels, and this ultimately benefits the heart. As per a report by the Cambridge University Press, the flavonoids in onions help lower the levels of LDL (the bad cholesterol) in obese people. Onions also prevent the blood platelets from sticking each other, which can lead to clotting and eventually, heart attacks. They also can prevent high blood pressure, thereby averting heart danger. Another study on rabbits showed that onions could prevent atherosclerosis. They achieve this by enhancing fibrinolytic (a process that results in the removal of small blood clots) activity.
- Lower Blood Sugar Levels
One study has proven that onion extract can help lower blood sugar levels. The study was conducted on diabetic rats, and the results were encouraging. One of the sulphur compounds in onions (S-methyl cysteine) and quercetin can have beneficial effects on blood sugar. However, it was found that onions exhibited the positive effect only when taken along with metformin, the anti-diabetic drug. In yet another study, polyphenols (especially the ones in onions) were found to play a role in glycaemic control.
- Promote Healthy Digestion
The digestive benefits of onions can be attributed to inulin, a fibre present in the vegetable. Inulin acts as a food source for the beneficial bacteria in the intestines. Consuming this fibre helps your body maintain good levels of the healthy bacteria. However, the thiosulfates in onions can cause harm to these beneficial bacteria (as they have antibacterial properties). Hence, if you are sensitive to the antibacterial properties of onions, do consult your doctor. Another soluble fibre in onions, oligofructose (which is a sub-group of inulin), was found to prevent and treat different types of diarrhoea. And the phytochemicals in onions can cut the risk of gastric ulcers. The natural prebiotics in onions can also help ease constipation. They are also believed to help treat stomach ache and stomach worms, though more research is warranted. Onion is known to cause migraine and flatulence in some people. Consult your doctor if this happens.
- Maintain Bone Health
Preliminary research suggests that onions can prevent age-related osteoporosis. According to Swiss researchers, a compound in white onions (called GPCS) can reduce bone loss. Though the study was conducted on rats, it does hold promise for humans.
Another study revealed that women who ate onions regularly had 5 percent more bone mass than those who ate less. Onion consumption was also found to have a beneficial effect on the bone density of women older than 50 years.
According to the Arthritis Foundation, quercetin in onions can inhibit the activity of leukotriene’s, prostaglandins, and histamines (all of which cause inflammation) in osteoarthritis and rheumatoid arthritis. Onion intake was also found to help treat joint pains.6. Prevent Inflammation and Other Allergies
We have already seen quercetin (and other flavonoids) in onions can help prevent inflammation. Onions also treat allergies by preventing the cells from releasing histamine.
Cooking with onions can help open and drain your sinuses. And the antihistamine properties of quercetin can also aid in reducing nasal congestion. Even eating a raw onion at night can help relieve congestion – the sulphur-compounds in the onion can break down the mucous.
Onions also possess antibacterial properties. As per one study, onion extracts acted against Streptococcus mutants and Streptococcus subrings, the bacteria responsible for dental caries and other allergies. Onions also possess antibiotic effects that can accelerate wound healing.
- Improve Immune System
Onions contain selenium that stimulates immune function. The mineral also prevents excessive immune response, which can have adverse effects. Immune cells deficient in selenium develop and reproduce inefficiently, and here’s where onions come into the picture. Such cells also have difficulty in producing the important proteins and transporting calcium.
Onions are also considered herbal medicine in Russia, where they are used to treat cold and flu
We also want to talk about a popular remedy here – sleeping with onions underneath your feet, placing them in your socks. Does this have benefits? Certain sources say that it eradicates infection and hydrates your body. Doing so can also strengthen your immune system. The reason behind this could be that the feet contain the nerve endings of all the organs of the body. Placing onions beneath the feet transfers their beneficial properties to your interiors. However, there is no research on this – and we don’t know how far the information is true.
You can also make onion tea for treating colds. This tea gives you an immunity boost and helps prevent ailments. Making the tea is as simple as cutting an onion, boiling it in water, and drinking the juice. This acts as a quick remedy for your cold and other illnesses. You can also add other ingredients like ginger for taste.
Even onion-honey syrup works wonders for common cold symptoms. Just slice an onion and add it to a saucepan. To this, add half a cup of honey. Gently heat until the onions turn translucent and soft. Take a spoonful of this syrup every 3 to 4 hours. For prevention, you can take 1 or 2 spoonful’s during the flu season. You can also use white onion with honey for similar results.
The anti-inflammatory properties of onions can also help improve asthma. This effect can be attributed to quercetin (an average onion contains 50 mg of it).
- Cure Ear Disorders
As per one report, though research is limited, most parents swear by onions to cure ear ailments. They insist that onion juice can work great to relieve earache. One way to do this is to heat up the onion, extract some of the juice, and pour a few drops into the infected ear. And this remedy, believe us, goes back to the 19thcentury.
All you need to do is place the onion in an oven at 450oF. Let it be for 15 minutes or until it becomes soft. Take out the onion – once it’s cool, cut it in half and squeeze the juice into a small bowl. You can strain the juice once, and using a medicinal dropper, pour a few drops of the juice into your infected ear.
An alternative is to place onion packs on the infected ear. Though the remedy is not scientifically proven, some people believe they might work.
- Promote Respiratory Health
According to an American study, patients with respiratory issues like asthma and allergic rhinitis can benefit from certain fruits and vegetables, onions being one of them.
The anti-inflammatory properties of onions can also help soothe respiratory ailments. If you are suffering from a respiratory illness, you can simply include onions in your diet (in addition to your medication) for quicker relief. Include onions in your salads and other foods.
- Improve Sleep
Onions contain prebiotics, which, as per a study, can improve sleep and even reduce stress. When the beneficial bacteria in the gut digest the prebiotic fibre, they multiply and improve gut health – and more importantly, release metabolic by-products. These by-products can influence brain function and induce sleep.
- Enhance Eye Health
The sulphur in onions improves the health of the lens of the eye. It stimulates the production of a protein named glutathione, which acts as an antioxidant. Higher levels of glutathione mean a reduced 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).
As per an Iranian study, onions can inhibit the growth of normal eye flora. This highlights the possibility of onions being a potential cure for common eye infections like conjunctivitis and blepharitis. In the study, onion juice was used as eye drops – which resulted in the benefits. You can try that too, but we recommend you consult your health care provider first.
Onion extracts can also aid in preventing the development of corneal haze.
- Are Good for Oral Health
Onions contain thiosulfates and thiosulfates (the sulphur compounds) that help reduce bacteria that cause tooth decay. And eating those raw is best – as cooking might destroy some of these beneficial compounds.
The vegetable is also rich in vitamin C that can keep the teeth healthy. It is also believed that onions can relieve tooth pain. However, there is less research on this.
But one downside of onions is that they can cause bad breath. Hence, wash your mouth thoroughly after consuming onions – especially if you are heading to a social gathering.
- Aid in Cholera Treatment
Onions were found to have an inhibitory effect against V. cholera, the microbe responsible for cholera. This can be attributed to the antibacterial effects of the vegetable.
- Prevent Blood Clots
Onions contain a compound called rutin, which can help prevent blood from clotting. In numerous mice studies, rutin was found to be the most potent anti-thrombotic compound. Clots occur in the arteries and veins – in arteries, the clots are platelet-rich while in veins they are fibrin-rich.
The rutin in onions helps block an enzyme (protein disulphide isomerase), which is released very quickly when blood clots form.
- Give an Energy Boost
The fibre in onions slows digestion and keeps the energy levels stable. The inulin in the vegetable helps maintain your stamina levels.
- Improve Sexual Health
Onions are one of the herbal medicines used in western Uganda for managing sexual impotence and erectile dysfunction. Even otherwise, the vegetable is known to have benefits for men. Taking onion juice with honey is known to increase fertility in men.
- Enhance Brain Health
Research suggests that the antioxidants in onions bind with the harmful toxins in the brain and flush them out of the body. And the sulphur-containing compounds in onions can slow down age-related memory loss. The extracts of onions have been found to maintain the hippocampus. However, a part of these memory fighting properties might be lost upon cooking. Hence, try your best to eat the fruit raw. Another sulphur-compound in onions, named di-n-propyl trisulphide, improves memory impairment. Onions are also believed to treat dizziness, epilepsy, and vertigo – though we have limited research on this.
- Help Cure Fever
Onion can be included as a food ingredient to cure fever. It can also prevent or treat nose bleeding, given its natural fumes, which can help the blood clot (externally).
- Reduce Oxidative Stress
According to a Chinese study, taking onion juice can help modulate oxidative stress. In yet another study, it was found that onions can also lower diabetes-induced oxidative stress. The quercetin in the vegetable can prevent diseases related to oxidative stress. It also protects the DNA against damage from oxidative stress. Another Argentine study attributes the ability of onions to reduce oxidative stress to their anti-inflammatory and antioxidant properties
- Ease Menopause Symptoms
Onions help during menopause as they support the liver and get rid of the waste hormones (40). Taking enough calcium is also imperative during this period. Onions contain calcium too and can help in this regard.
Credits to Ravi Teja