30 Top Health Benefits of Onions

Onions are used for their texture and flavor in so many different recipes across so many different cultures, but are they good for your health? They sure are! There are many health benefits of onions.

There’s so much to learn about the health benefits of onions. So, of course, we put together a guide to onions including the pros and cons.

Different Types of Onions

Onions are allium vegetables.

There are somewhere between 600 and 900 different species of onions. However, most people use around 7 varieties of onions pretty regularly in their cooking.

The 7 varieties of onions are the ones you will easily find in any grocery store, or listed in almost any recipe.

All of these onions contain just about the same health benefits, with the exception of the yellow and red onions offering a heftier dose of antioxidants.

Yellow Onions

Yellow onions are probably the most versatile onion there is.

If you could only use one onion in your recipes for the rest of your life, yellow onion would be the one to choose.

These are the most pungent onions and have the most oniony flavor.

If the recipe you’re using calls for an onion, but doesn’t specify the type, grab a yellow onion at any grocery store.

White Onions

White onions have a milder and sweeter flavor than yellow onions. These are one of the most commonly found onions at any grocery store.

Red Onions

Red onions are generally more sweet and mild enough to eat raw, but have a little more kick than white onions. These are easy to find at any grocery store.

Green Onions

Green onions are just immature onions that haven’t formed into a bulb yet.

The entire plant is eaten, except the roots. These are common and easily found in the refrigerated section of the produce department of your grocery store.

Sweet Onions

Sweet onions are large but flatter than other onions. They also contain more sugar than other onions.

Sweet onions are good for caramelizing, or a nice size for making baked onion rings. These will be easy to find in almost any grocery store.

Shallots

Shallots are small onion that almost resembles garlic in shape and they have a bit of a garlicky flavor as well. These onions are usually near the garlic in your produce section.

Leeks

Leeks look like overgrown green onions, and they have a nice flavor that mellows and softens when leeks are cooked.

They are part of the onion family, but they are definitely more prominently used in other cultures. This is the only onion I would say you could have a little issue finding, depending on your grocery store options.

35 Health Benefits of Onions

1. Boost Immune System

Onions contain antioxidants that fight free radicals in our bodies.

Research shows that one particular antioxidant, quercetin, helps to protect our immunity in a couple of ways. Quercetin boosts the immune system and fights inflammation.

2. Fight Inflammation and Allergies

Quercetin, which fights inflammation, is also a flavonoid that acts as a natural antihistamine.

It works by blocking the production and release of histamines, which are the body’s allergic response.

3. Maintain Bone Health

That same anti-inflammatory antioxidant, quercetin, protect damage to our bones from free radicals. It also inhibits the development of bone breakdown cells, making our bones stronger for longer.

4. Promote Gut Health and Healthy Digestion

Onions contain a lot of prebiotics and fiber, which are healthy for the gut and keep digestion working properly.

The gut plays a very important role in the good health of the rest of your body and your mind.

Gut-healthy foods, like onions and other food source fiber and prebiotic options, are essential.

5. Lower Blood Sugar Levels

Raw red onion, in particular, is said to lower blood sugar levels significantly and help improve insulin resistance.

Onions have been shown to possibly to stimulate insulin production by the pancreas and block the breakdown of insulin in the liver This increases the amount of insulin and reduces sugar levels in the blood.

6. Improve Heart Health and High Blood Pressure

Not only do the antioxidants in onions reduce inflammation in the heart, but they also lower cholesterol levels and protect against blood clots.

7. Fight Cancer

Onions are said to be one of the best anti-cancer foods.

They disrupt communication between cancer cells and promote an unfavorable environment for the cells, which makes it difficult for them to grow.

Regular consumption of onions may lower cancer risk.

8. Improve Respiratory Health

Studies show that people with respiratory illnesses like asthma and allergic rhinitis can benefit from the regular consumption of onions.

The anti-inflammatory properties of onions can reduce swelling in the throat and irritation of the lungs.

9. Cure Ear Problems

It is said that onion juice in the ear can reduce pain and heal an ear infection. There is no scientific evidence to back up this claim, but this home remedy goes way back to the 19th century.

10. Improve Sleep

The probiotics that onions contain are said to contribute to improved sleep.

Probiotics have beneficial effects on good gut bacteria.

When good bacteria multiply in the gut, it influences brain function and improves sleep. It also reduces stress, which is helpful for improving sleep.

11. Improve Oral Health

Onions produce sulfur compounds that help reduce tooth decay causing bacteria in the mouth.

Eating them raw is best to get the most out of this health benefit. It’s also said that onions can relieve tooth pain, although there is no scientific evidence of this.

12. Enhance Vision and Eye Health

The sulfur compounds in onions stimulate the production of a protein named glutathione.

Glutathione acts as an antioxidant and reduces the risk of glaucoma, macular degeneration, and cataracts.

13. Antibacterial Properties

Onions have antibacterial effects which can kill certain bacteria in the body.

For this reason, onions have been used to treat cholera and may be helpful at fighting all sorts of infections.

14. Improve Sexual Health

Onions have been used as herbal medicines in some cultures to manage sexual impotence and erectile dysfunction.

15. Boost Energy

Onions are high in fiber which slows digestion and gives you more sustained energy.

16. Help Prevent Blood Clots

Rutin, a compound found in onions, can help prevent blood from clotting.

On the other hand, fumes from onions can help a nose bleed stop, because it helps the blood clot externally.

17. Help Reduce Fever

Eating onions while you have a fever may reduce or even eliminate your fever.

18. Improve Brain Health

Research has shown that it’s possible that the antioxidants in onions can bind with toxins in the brain and help flush them out of the body.

Raw onions can also slow down age-related memory loss. Other compounds in onions can even improve memory impairment.

19. Reduce Menopause Symptoms

Onions contain calcium which helps ease menopausal symptoms in women.

Onions also support the liver, and can help rid the body of waste hormones. Eating a diet rich in onions all of the time is great prevention and management for these symptoms.

20. Reduce Oxidative Stress

The antioxidant quercetin in onion can protect against DNA damage from oxidative stress.

Quercetin can also prevent diseases related to oxidative stress. This ability is said to be because of onions’ antioxidant and anti-inflammatory properties.

21. Improve Insulin Resistance

Onions not only improve insulin resistance, but they also fight against diabetes-induced oxidative stress.

This hasn’t been studied on people, just human cells and animals. However, there is strong evidence that onions have important flavonoids that improve diabetic status in cells.

22. Anti-Aging for Skin

The vitamins A, C, and E in onions are powerful antioxidants that work against the damage caused by UV rays.

They can help prevent free radical damage that ages the skin. Vitamins and sulfur protect your skin and keep it supple, while quercetin fights wrinkles.

23. Treats Acne

An onion mixture applied topically can be a treatment for acne and pimples.

If you can stand the smell, it is said that 1 tablespoon of onion just and 1 tablespoon of olive oil mixed together and spread over your face for 20 minutes will heal acne. This is because of onions strong antibacterial compounds.

24. Removes Dark Spots From Skin

Skin spots and pigmentation can be removed by making a facial mask with equal parts of onion juice and yogurt.

The onion’s rich phytonutrients and antioxidants remove the impurities from your skin. This should be done daily for the best results. You can also use onion extract rather than onion juice.

25. Treats Bug Bites and Bee Stings

The antioxidant and anti-inflammatory properties will reduce the stinging, itching, and burning of a bug bite or bee sting.

Just cut an onion and place the cut side on the bite or sting until you feel relief.

26. Promotes Hair Growth

In a recent study, participants who washed their hair with onion juice experienced more hair growth than those who didn’t.

Onion juice increases blood supply to the hair follicles, which stimulates hair growth.

The sulfur in onions can also stimulate collagen production and results in thicker, healthier hair.

Apparently, onion juice can be combined with essential oils to tame the smell. Lavender was suggested in one study and it has even more benefits for your skin and hair so it may be a good ingredient to add.

27. Helps Improve Dandruff

The strong antibacterial properties of onions can stop dandruff from continuing to develop.

Use onion juice and fenugreek seeds. Soak 3 tablespoons of fenugreek seeds in water overnight. The next day, grind them into a fine paste and add 2 tablespoons of fresh onion juice. Mix well and apply the pack to your scalp. Leave it on for 30 minutes then rinse with lukewarm water.

You’ll need to repeat this process probably several times.

28. May Reverse Gray Hair

There is no evidence of this one, but it is said that onion juice will start to improve the sheen of your hair, and with time you may see the reversal of gray.

29. Maintain Hair Color

Onion juice and mustard seed oil are said to help maintain your natural hair color.

30. Get Rid of Head Lice

Applying onion juice to your scalp and leaving it under a shower cap for two hours, three days straight is said to kill off lice.

This can be done every two weeks for a month to prevent the return of lice. After each wash, use a knit comb to remove the head lice.

Possible Side Effects of Onions

Lots of people tolerate onions just fine and eat them all the time. Still, there are some instances where onion consumption can be potentially problematic.

Some People May Be Allergic or Intolerant

Although a true onion allergy is rare, an intolerance to onions is fairly common.

Typical symptoms are related to gastric distress, but headache and itching can also be a sign of an allergy to onions.

May Trigger/Irritate IBS Symptoms

If you suffer from Irritable Bowel Syndrome, onions may be one food you want to avoid. They can be irritating to the digestive system if there are already digestive issues present.

May Cause Heartburn

Onions stimulate gastric acid, so they may cause or worsen heartburn in some people.

Drug Interactions

Some medications are broken down by the liver. Because onion might slow down the process, it could increase side effects from medications.

Bad Breath

The pungent smell of onions is produced by chemicals in the onions containing sulfur. This can cause halitosis, or bad breath if you eat a lot of onions. It’s not dangerous, just unpleasant.

How to Store Onions

Different onions should be stored in different ways. There’s a quick overview of that below or you can read in more detail about onion storage here.

Whole, Raw Onion Storage

Whole, raw onions need to be stored in a cool, dry place. Your pantry or cellar is ideal, but anywhere out of direct sunlight and where the onions are well-ventilated will be just fine.

Cut or Cooked Onion Storage

Cut raw onions and cooked onions should be stored in an airtight container in your refrigerator.

Green Onions and Leeks Storage

Both leeks and green onions should be stored in your refrigerator. Green onions should have the root end submerged in 1 inch of water and the other end covered with a plastic bag.

Alternatively, you can purchase a container meant to store green onions.

Leeks should be left unwashed and uncut for storage. Wrap leeks in plastic wrap to keep them fresh and keep the smell from permeating other foods in your fridge.

Raw vs. Cooked Onions

Raw onions and cooked onions both have amazing health benefits,

No matter how they are served, they are packed with powerful antioxidant properties no matter the type of onion you choose.

Overall health can be improved with the consumption of onions’ beneficial compounds. But the organic sulfur compounds, in particular, are more powerful in raw onions.

The sulfur-containing compounds are responsible for lowering the risk of heart disease, lowering your body’s blood sugar, anti-cancer properties, and fighting off other types of chronic diseases.

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Health Benefits of Onions