46 Benefits And Side Effects of Onions

Onions are a member of the genus Allium in the lily family, which also includes garlic, leeks, chives, and shallots. Onions have been used for thousands of years as food and medicine. They contain many healthful compounds including vitamins C and K, folate, potassium, fiber, and antioxidants. The bulb contains sulfur-containing compounds called thiosulfinates that give onions their characteristic odor and flavor.

This vegetable has a rounded shape and a thin skin. It has a sweet taste and is often sliced or chopped into pieces before being cooked. An onion can be eaten raw in salads, but it is usually cooked to remove its strong smell and bitter taste. They are available in many varieties 

Different types of onions 

White Onion: These onions are milder than red ones. White onions are sweeter and less pungent than yellow onions.

Red Onion: Red onions are more pungent than white onions. They are generally smaller than yellow onions.

Yellow Onion: This type of onion is milder than red onions. Yellow onions are sweeter and more pungent than green onions.

Green Onion: These onions are the mildest among all types of onions. 

onion benefits and side effects

Nutrients In Onion

Onions are an excellent source of vitamin B6, manganese, copper, dietary fiber, and folic acid. They are also rich in vitamin C, iron, phosphorus, magnesium, calcium, zinc, and selenium. They are low in calories (only about 46 per cup) and fat.

They are also rich in 

Antioxidants – Onions contain powerful antioxidants called quercetin and kaempferol. Quercetin is a flavonoid (a type of antioxidant) that helps prevent cell damage.

Iron – Onions are good sources of iron. Iron is important for blood formation and oxygen transport.

Folate – Folate in onion is needed by our bodies to make new cells and repair damaged tissue.

Vitamin C – Onion has vitamin C which is necessary for collagen production, wound healing, and immune function.

Potassium – Potassium is onion is essential for muscle contraction and nerve transmission.

Dietary Fiber – Dietary fiber is part of plant matter that cannot be digested by humans. It passes through the digestive system without being absorbed. Some people need more dietary fiber than others. Onions are rich in dietary fibers. 

Phosphorus – Phosphorus in onion helps bone growth and energy metabolism.

Magnesium – Onion has magnesium which is involved with over 300 biochemical reactions in the body. It plays a role in muscle contractions, nerves, bones, teeth, and hormones.

Calcium – Calcium is one of the most abundant minerals in your body. It is needed for building strong bones and muscles, regulating heartbeat, and helping nerves transmit messages.

Zinc – Zinc is needed for proper growth and development, immunity, reproduction, and wound healing.

Selenium – Selenium is needed for normal thyroid function, protein synthesis, and immune response.

Health Benefits of Onion

1. Good For Heart Health

Onions are a great source of vitamin B6, potassium, fiber, folic acid, manganese, copper, iron, calcium, magnesium, phosphorus, niacin, thiamine, riboflavin, pantothenic acid, and vitamins A and C. 

These compounds improve our cardiovascular health.

Onion contains antioxidants like quercetin, which help prevent cancer and cardiovascular disease. 

Studies show that eating onions lowers total cholesterol and LDL cholesterol while raising HDL cholesterol (1). In addition, it reduces blood pressure, platelet aggregation, and inflammation.

2. Rich In Antioxidants

Onions are loaded with antioxidants, according to research published in the journal Food Chemistry. Scientists found that red onions contained twice as much antioxidant activity as white ones. They also discovered that cooking onions increased their levels of vitamin C, potassium, iron, and fiber.

Red onions are especially good for your health because they contain anthocyanin compounds, which help protect against cardiovascular diseases and cancer (2). Anthocyanins are powerful antioxidants that give fruits and vegetables their purple color.

3. Fights Cancer

Onion is one of the food that help fight cancer as consuming onions reduce the risk of developing colorectal cancers. 

A study published recently in the journal Nutrition & Cancer found that people who ate onions had lower rates of colon and stomach cancer compared to those who did not eat onions. This association was held even among participants who consumed onions frequently.

The researchers believe that the anti-cancer properties of onion are due to the presence of sulfur compounds called thiosulfinates. Thiosulfinates inhibit cell proliferation and induce apoptosis or programmed cell death (3).

They may also act synergistically with other dietary factors such as fiber and antioxidants.

4. Promotes Weight Loss

onion promotes weight loss

Onions are great at promoting weight loss because they help boost metabolism. Onions contain quercetin, a flavonoid compound that helps burn fat. 

They are also low in calories ( 40 calories per 100 grams) which means you can eat them without worrying about much calorie overload.

Also, they contain dietary fibers that promote satiety and control overeating. 

5. Good Source of Sulfur

Sulfur in onions is responsible for the bad and pungent smell that we experience after eating onions.

However, sulfur also provides many benefits such as inhibiting the formation of biochemical chains responsible for asthmatic conditions, aiding in treating severe cough by facilitating the melting of phlegm, strong aroma, and energy boost provided by onion juice can bring a person out of the unconscious.

6. Increase the Production of glutathione

Onions contain sulfur compounds called thiosulfinates, which help our body produce glutathione, a powerful antioxidant that helps protect us against cancer and heart disease. Onions also contain quercetin, a flavonoid compound that may reduce inflammation and improve blood flow (4).

7. Regulate Blood Sugar

Eating onions may help control blood sugar, especially for people with type 2 diabetes or pre-diabetes. Onions are rich sources of quercetin, an active ingredient that may improve blood sugar regulation (5).

Dietary fibers in onion also help regulate blood sugar. Quercetin helps block enzymes that break down carbohydrates, so it slows digestion and absorption. 

It’s thought that this mechanism improves insulin sensitivity, helping to keep blood sugar under control.

8. Improve Bone Density And Reduce Risk of Fractures

Onions contain many nutrients that help prevent osteoporosis and lower fracture rates. They’re rich in vitamin K, folate, potassium, fiber, iron, manganese, magnesium, phosphorus, protein, riboflavin, thiamine, zinc, copper, calcium, and niacin.

They also contain phytochemicals called polyphenols, which may improve bone health. Polyphenols include flavonoids, phenolic acids, anthocyanins, and lignans.

Flavonoids and phenolic acids may inhibit the activity of enzymes that break down collagen (6) and cause bones to become brittle. Anthocyanins and lignans may stimulate the production of estrogen, which helps maintain healthy bones.

One study (7) found that women who ate onions every day had a 20% reduction in hip fracture risk compared to those who didn’t eat them at all. 

Another study showed that menopausal women who consumed 1/2 cup of raw onions per day reduced their risk of developing osteoarthritis by 30%.

Another recent study suggests that eating onions regularly may increase bone density. Researchers at Harvard University looked at data from 1,814 men and women over age 65. 

The subjects were asked about their diets, including how often they ate onions. 

After adjusting for other variables, the scientists found that those who ate onions more than once per week had significantly higher bone mineral density than those who didn’t eat them at all.

9.  Antibacterial Properties

Quercetin, found in onions, has been shown to inhibit the growth of Helicobacter pylori and methicillin-resistant Staphylococcus aureus (MRSA) (8).

 In addition, quercetin damages the bacterial cell wall and membrane, making it difficult for bacteria to grow.

10. May Boost Digestive Health

onion improve digestion

Onions contain prebiotics — nutrients that feed beneficial microorganisms called probiotics. Prebiotics improve digestion and support immune function. They also protect against harmful pathogens like E. coli and salmonella. (9)

In addition, onion juice contains polyphenols and antioxidants that fight free radicals and reduce inflammation.

Prebiotic fiber helps increase the population of good bacterial species in the intestine. These microbes play important roles in maintaining intestinal homeostasis and protecting against pathogenic organisms. 

Fiber feeds the friendly bugs, helping them multiply and flourish.

11. Reduce Inflammation And Other Allergies

The compound quercetin is an anti-inflammatory agent found in onions that helps reduce inflammation (10).

It inhibits the release of histamine, which causes itching and sneezing. In addition, it slows down the growth of bacteria, making it helpful in treating infections

Onion juice also contains antioxidants that protect against free radicals, which are harmful compounds that cause cell damage.

Antibiotic properties of onion speed up the process of wound healing. 

A study conducted in 2011 showed that people who ate raw onions had lower levels of IgE antibodies, which indicate allergies.

12. Improve Respiratory Health

The onion is one of the oldest known medicinal plants. In ancient times, onions were used to treat respiratory problems such as colds and flu.

Today, onions are still being used to promote good health. They contain powerful antioxidants which help fight against free radical damage. 

Onions are great for improving respiratory health because onions contain sulfur compounds called thiosulfinates. These compounds help protect against infections and inflammation in the lungs.

Thiosulfinates also help prevent cancerous cells from growing. Onions are rich in quercetin, a flavonoid compound that helps fight infection and inflammation in the body. Quercetin also protects against heart disease and diabetes.

One study found that eating 1/2 cup of raw chopped onion daily reduced the risk of developing lung cancer by 30 percent. 

13. Regulate Blood Pressure

Onion contains potassium, which helps maintain normal blood pressure. Potassium regulates sodium and water balance in the body, helping prevent fluid retention and swelling. 

Quercetin, an antioxidant in onions helps lower inflammation and prevent cardiovascular diseases like hypertension.

A study (11) in 70 overweight adults with high blood pressure found a daily dose of 162 milligrams of quercetin-rich onion extract lowered systolic blood pressure (the top number) by 3 – 6mm Hg compared to a placebo.

14. Good For Eyes

onions are good for eyes

The onion contains many vitamins and minerals that are good for our body and mind. They include vitamins A, B1, B2, B6, C, E, K, folate, potassium, magnesium, phosphorus, zinc, copper, manganese, iron, calcium, selenium, sodium, chlorine, and sulfur. 

The Antioxidant properties of onions make them useful in treating eye disorders such as glaucoma, macular degeneration, diabetic retinopathy, and age-related macular degeneration.

15. Good For the Brain

The onion is one of nature’s most powerful foods. It contains high levels of antioxidants, vitamins, minerals, and phytochemicals.

These nutrients are essential for brain health. Research suggests that onions might also help prevent or treat dementia, improve memory function, and protect against oxidative stress. 

In fact, onions could even play a role in preventing Alzheimer’s disease (12).

16. Good For Immune System

Onions are rich in selenium, which helps improve the body’s natural defenses against infection. They also help reduce inflammation and boost the body’s ability to fight off infections (13).

In addition, onions inhibit the production of histamine, which causes allergic reactions. This makes onion juice effective in treating coughs, bronchitis, pneumonia, and asthma.

Vitamin C in onion enhances the production of white blood cells, and further strengthens our immunity.

With stronger immunity, we are at a lower risk of getting a cough, cold, fever, flu, etc.

The anti-inflammatory properties of vitamin C also benefit against respiratory problems like cough and cold. 

Other nutrients like zinc, iron, potassium, magnesium, etc in onion also contribute to better immune health.

The best way to use onions is to chop or grate them into a cup of boiling water. Let it cool down and drink it every day. You can add some honey too.

17. Relieve Earache

Earaches are painful enough, but when you’re dealing with an infected eardrum, it can be downright miserable. Ear infections are common among children and adults alike. They often result in hearing loss and permanent damage to the inner ear.

The antibacterial and antioxidant properties of onion help in relieving earache.

For this, gently put a few drops of fresh onion juice in the ears or wrap an onion juice-soaked cotton cloth around the ear. 

But if this remedy doesn’t provide relief even after 3 days, it is better to stop home remedies and go see a doctor.

18. Improve Sleep

onion improve sleep

Onions help improve sleep quality by reducing inflammation and increasing serotonin levels in the brain. 

They also contain quercetin, a flavonoid compound that helps regulate the production of melatonin, the hormone responsible for falling asleep.

 Quercetin also increases blood flow to the skin, helping you relax.

19. Reduce Stress Levels

Stress affects everyone differently. Some people find it difficult to cope with stressful situations while others get stressed out easily. 

When you feel anxious, angry, sad, or frustrated, try eating an onion. Onions have been shown to lower cortisol levels, which reduces stress and boosts mood.

20. Help Maintain Oral Health

Onions are very beneficial for oral hygiene.

They contain powerful antioxidants called quercetin and kaempferol, which help prevent tooth decay (14).

Because of its anti-microbial properties, chewing a few raw onion slices for 2-3 minutes can potentially kill all germs in the oral area like teeth and gums. It fights off oral infections and tooth decay.

Additionally, onion juice helps fight bad breath and gum disease. Onions contain sulfur compounds that kill bacteria and fungi in the mouth, making them effective against cavities and gingivitis.

They cleanse the mouth and teeth without causing irritation. Onion juice has antibacterial properties that kill bacteria and fungi on the tongue, gums, and inside the mouth. It also kills germs that cause bad breath.

21. Help With Nosebleeds

Onion helps in treating nosebleeds because it contains quercetin, an anti-inflammatory and antioxidant compound.

External use of onion juice is also effective.

To use this method, simply slice off the root end of the onion, peel away the outer layers, and place them directly over the affected area. Leave the onion there until the bleeding stops. Then remove the onion and wash it thoroughly.

22. Prevent Blood Clots

Onion contains sulfur compounds called thiosulfinates, which help prevent platelets from sticking together and forming clots (15). This helps keep blood flowing freely through the body.

They also contain rutin, which is a flavonoid found in onions that prevents blood from clotting. This makes it useful for people who are prone to forming blood clots, such as those who suffer from deep vein thrombosis (DVT).

23. Improve Sexual Health

Onion is a natural aphrodisiac. Onion juice contains sulfur compounds that help improve blood flow to the penis. Onions contain quercetin, which helps reduce inflammation and swelling.

One study found that men who ate onions regularly had lower rates of erectile dysfunction than those who did not eat them. 

Another study showed that men who consumed onions daily were less likely to develop prostate cancer than those who did not consume onions (16).

24. Help Cure Fever

onion help cure fever

Onion juice is one of the oldest remedies known to mankind. In ancient China, it was used to treat fevers. Today, onion juice is still used to help heal cuts, wounds, bruises, and even burns. Onion juice works because it contains an enzyme called alliinase, which stops bleeding. Allicin, another compound found in onions, can also stop bleeding.

To make onion juice, you simply peel off the outer layers of an onion and put the rest into a blender. Then add some water and blend until smooth. You can use this liquid directly on the wound or apply it externally to stop bleeding.

You can also drink onion juice to relieve fever. Simply slice up an onion and boil it in a pot of water. Let the mixture cool down and strain out the onion pieces. Drink the resulting broth every hour to prevent further fever.

25. Ease Menopause Symptoms

Menopause symptoms include hot flashes, night sweats, mood swings, insomnia, vaginal dryness, weight gain, urinary incontinence, bone loss, memory problems, and heart disease. 

Onion contains phytochemicals called quercetin and kaempferol, which may help ease menopausal symptoms. Quercetin helps reduce hot flashes and night sweats (17), while kaempferol reduces vaginal dryness

If you’re suffering from hot flashes, onions can help ease those uncomfortable feelings. Onions contain quercetin, a compound that reduces inflammation and relieves pain. Quercetin also increases circulation, helping to cool down your body during hot flashes.

Beauty Benefits of Onion For Skin And Hair

26. Improve Skin Glow

Onions are great for improving skin glow because they contain sulfur compounds called thiosulfinates. 

These compounds help reduce inflammation, improve blood flow, and stimulate collagen production.

 They’re also known to fight wrinkles and prevent premature aging.

27. Anti-Aging Benefits

onion provide anti aging benefits

Massaging your face with onions helps stimulate blood flow and promotes collagen production. Collagen is the main component of connective tissue, which keeps our skin firm and elastic. As we age, collagen levels decline. 

By massaging your face with onions, you can increase collagen production and keep your skin looking young.

In addition to improving your appearance, onions help reduce wrinkles and eliminate blemishes. When applied directly to the skin, onions help cleanse pores and heal pimples. 

You can make homemade onion masks by mixing equal parts chopped onions and olive oil. Apply it to your face twice daily. For best results, massage the mixture into your skin overnight.

You can also apply onion juice to your skin. To do this, cut off the root end of an onion and place it in a bowl. Cover the bowl with cheesecloth and let sit for 24 hours. Squeeze out the liquid and mix it with honey. This mask works well for treating acne scars.

28.  Help With Acne Treatment

Acne is a common skin condition that affects millions of people worldwide. Acne occurs when oil glands become clogged, causing excess sebum (skin oil) to build up beneath the surface of the skin. This buildup causes bacteria to grow, resulting in pimples, blackheads, whiteheads, and cysts.

Onions help treat acne (18) because onions contain sulfur compounds that help reduce inflammation. They also have antibacterial properties that kill bacteria and clear blocked pores.

To use onion to treat acne, simply slice off the root end of the onion and place it directly over the pimple. Leave it there for 15 minutes (or as long as you are comfortable doing so). Then rinse the area thoroughly with warm water. Repeat this process two times per day until the skin clears.

If you’re not familiar with the term “root end”, it refers to the bottom portion of the onion where the stem meets the bulb. This is the part of the onion that contains most of the nutrients and is usually discarded when cutting an onion.

29. Treat Skin Pigmentation And Remove Dark Spots

Onion juice is rich in vitamins A, B6, and C. These vitamins help improve the quality of your skin. Vitamin A prevents premature aging and wrinkles. Vitamin B6 reduces inflammation and speeds up cell turnover. Vitamin C promotes collagen production (19), making your skin look younger.

The onion juice you use must be fresh. You can buy it online or at local grocery stores. To make the juice yourself, peel onions and cut them into slices. Put them into a blender and blend them until smooth. Make sure to strain out the pulp to avoid clogging the machine.

You can apply the onion juice directly onto your face or mix it with water and wash it off with lukewarm water. For best results, do this twice daily.

30. Treat Stings And Bites

onion treats stings and bites

Onions are one of the best home remedies for treating stings and bites. They help prevent infection and speed up healing. You can use onions to treat insect bites, bee stings, jellyfish stings, spider bites, snakebites, scorpion stings, mosquito bites, and even sunburn. 

Here are some tips for how you can make onion juice to help ease the pain of a sting or bite.

  1. Cut off the root end of the onion. This will allow the rest of the onion to drain out naturally. If you want to speed things up, you can put it into a strainer over a bowl.
  2. Peel the skin off the onion.
  3. Put the peeled onion into a blender and blend until smooth.
  4. Pour the mixture into a glass jar and store it in the refrigerator.
  5. To apply the onion juice, dab a cotton ball onto the area where the sting or bite occurred. Leave it there for about 10 minutes. Then rinse it off with water. Repeat this process every hour.
  6. You can also mix onion juice with honey to make a paste. Apply it directly to the affected area.

31. Promote Hair Growth

onion promotes hair growth

Onion juice contains sulfur, which helps promote hair growth (20). You can use it directly on your head or mix it into shampoo, conditioner, or even toothpaste.

If you are looking for some extra volume, try mixing it with olive oil.

32. Help Treat Dandruff

Onion juice works as a great natural remedy for dandruff. The active ingredient in onions is called quercetin, which is known to fight against fungi and bacteria.

Allicin, another compound found in onion, is also beneficial for fighting dandruff because it prevents the growth of bacteria and fungi on the scalp (21).

You can use onion juice or onion paste to apply directly to the scalp to combat dandruff. You can also mix onion juice with fenugreek seeds to make a homemade dandruff shampoo.

33. Help Reverse Gray Hair

Onion juice contains an enzyme called alliinase which helps reverse grey hair. However, there is no scientific evidence supporting the Onion’s ability to reverse grey hair.

34. Maintain Hair Color

Onion juice can be applied to hair to give it a shine. Mixing onion juice with Mustard Oil helps keep the natural color of your hair. Onions are rich in vitamin B6, which is essential for healthy hair growth. Vitamin B6 aids in protein synthesis, which promotes cell division and repair.

Mix 2 tablespoons of raw onions with 3 teaspoons of olive oil. Massage into hair and let sit overnight. Rinse out the next morning and shampoo. For best results use every week.

35. Eliminate Head Lice

Onion juice has been used for centuries to eliminate lice from children’s heads. It is effective at killing lice without causing any damage to the scalp.

Side Effects of Onion

1. May aggravate IBS symptoms

onion may aggravate IBS symptoms

Onions may aggravate irritable bowel syndrome (IBS) symptoms (22,23). If you experience severe abdominal pain, diarrhea, bloating, gas, nausea, vomiting, or constipation, it might be wise to limit your consumption of onion products.

For example, raw red onions contain substances called fructans, which can cause digestive issues. And eating too many onions can lead to flatulence and bloating.

2.  May Cause Allergic Reaction In Some People

Avoid onions if you are allergic (24) to them. Some of the allergic reactions that may arise due to onions are 

  • Asthma
  • Sinus infections
  • Eczema
  • Long-lasting rashes
  • Redness

3. May Cause Eye Irritation

Chopping onions produce Lachrymatory factor (LF), which causes tears to come from your eyes. LF is a compound found naturally in onions. If you cut an onion without wearing glasses, you might notice some irritation around your eyes. This is because the gas produced by the onion can cause eye irritation (25).

To avoid tearing up, chill your onion before chopping it. You can do this by putting the onion into a bowl filled with ice water. Alternatively, you could put the onion in the refrigerator for 15 minutes prior to slicing.

Lighting a match helps reduce the amount of LFG produced during the process of chopping an onion. When lighting a match, hold it close to the onion. As soon as the flame touches the onion, blow out the flame. Doing this will reduce the amount of gas produced during the chopping process.

4. May cause heartburn

Onions are known for causing heartburn. It’s one of the most common side effects of consuming too many raw onions. 

As per a study people who consume onions (26) frequently experience symptoms like burning sensations in the chest, throat, or stomach. These feelings usually occur within 30 minutes of eating onions. This is because onions contain compounds called thiosulphinates, which increase acid production in the stomach.

Onions contain an enzyme called Alliinase that breaks down Glutamine, which causes the Lower Esophageal Sphincter (LES) to relax.

To avoid heartburn caused by onions, eat them in moderation. You can try adding them to dishes such as salads or sandwiches. You can even add them to soups or stews. If you do find yourself experiencing heartburn after eating onions, try taking antacids or drinking water.

5. May Cause Bad breath

Onion contains sulfur compounds that produce strong smells. Onions contain thiosulfinates, which irritate the lining of the mouth. Both onions and garlic will give you a foul odor.

To avoid bad breath caused by onions, eat onions in moderation and rinse your mouth with water after eating onions.

Eat cooked onions as they are less likely to cause bad breath in comparison to raw onions.

Properly brushing your teeth will remove onion parts stuck between the teeth and help get rid of bad breath.

6. Drastic Decrease In Blood Sugar Levels

onion may interact with diabetes medication

Onion extract contains quercetin and methyl cysteine, both of which can help lower blood sugar levels.

Polyphenols in onions can also improve glucose metabolism (27). Research published in the Journal of Agricultural and Food Chemistry showed that polyphenols in onions improved glucose metabolism in diabetic mice.

 Diabetic mice received either a normal diet or one containing onions. At the end of the experiment, researchers checked the mice’s blood sugar levels. Those who ate onions had significantly lower blood sugar levels than mice who did not eat onions.

However, eating too many onions may drop our blood sugar below the normal range and lead to symptoms like shakiness, sweating, headache, nausea, irregular heartbeat, irritability, etc.

If you are on diabetic medication, it is better to limit the intake of onions as they may interfere with diabetic medication (28) because of their blood sugar-regulating properties.

7. Gastric Burning

Onion contains an enzyme called alliinase which causes stomach acid to rise in the body. Allicin, another compound present in onion, increases blood pressure, especially in those who are hypertensive. 

This effect is due to allicin blocking potassium channels in cells lining the walls of the arteries.

As a result, the heart needs to work harder to pump blood around the body. In addition, allicin inhibits prostaglandins, chemicals that relax smooth muscle in the digestive tract, leading to cramping, bloating, and nausea.

8. May Cause Skin Irritation

Onion juice contains sulfurous compounds, which are known irritants. Sulfuric acid is found naturally in onions and garlic. In addition, it is present in many foods such as eggs, dairy products, meat, fish, and even some fruits like apples.

When used externally, sulfurous compounds in onion cause skin irritation and rashes in some people. 

If you apply onion juice directly onto the skin, you might notice redness, itching, burning sensation, or blisters.

But it may vary from person to person. Some people will not experience any such symptoms and some may experience these symptoms even with a small amount of onion or onion juice.

If you have an onion allergy, you are more likely to experience these symptoms.

9. Drastic Drop In Blood Pressure

onion may interact with blood pressure medication

A study published in the journal of  Hypertension found that eating onions daily lowered blood pressure among adults over 50. Participants who consumed onions every day had lower systolic and diastolic blood pressures than those who never ate them. 

Researchers believe that the compounds in onion called quercetin and thiosulfinates may play a role in lowering blood pressure. Quercetin is known to improve cardiovascular health, while thiosulfinates are believed to relax blood vessels.

Potassium in onion also helps in lowering blood pressure because of its vasodilating properties.

However, overeating onions may lower our blood pressure below the healthy range and increase the risk of hypotension symptoms such as blurred vision, dizziness, fainting, fatigue, and troubled concentration.

If you are on blood pressure medication, eat onions in moderation and after consulting with your doctor to avoid the risk of onion-drug interaction.

10. Anticoagulant Property

Onion contains an enzyme called alliinase which inhibits blood clotting. This property makes it useful in treating varicose veins, where blood flow becomes sluggish due to vein dilation. 

In addition, onion juice is recommended for treating venous insufficiency. 

However, one should avoid consuming onions if there is any history or taking drugs known to inhibit blood clotting (29).

11. Onion And Drug interaction

Onions contain substances that may make some medications less effective. This includes anticoagulant drugs such as warfarin, clopidogrel, aspirin, and heparin.

These drugs help prevent blood clotting and treat conditions like stroke and heart attack. If you take one of these drugs and eat onions, it could increase the risk of bleeding.

There is little evidence about how many onions you need to eat before there is a problem, but there is no harm in eating just a few slices. However, if you regularly consume large amounts of raw onions, talk to your doctor.

How To Use Onions For Cooking/Eating

Onion tears are caused by an enzymatic reaction. This happens when the enzymes in the onion break down proteins, causing the liquid inside the onion to turn into steam. If you don’t want to see tears, try one of these methods:

  1. Freeze the onion before slicing it.
  2. Cut the onion thinly.
  3. Chew gum while cutting the onion.
  4. Put the onion in the refrigerator for 10 minutes before chopping.
  5. Dip the onion in cold, running water for 10 minutes.
  6. Cook the onion slowly over low heat.

How To Add More Onions To Your Diet

Here are some ways to incorporate onions into your diet:

  1. Add chopped onions to salads. – Onion salad is a popular appetizer at parties. It’s easy to make and can be served with many different types of dishes.
  2. Make onion soup. – Onion soup is another classic dish. The flavor is very rich and delicious.
  3. Add sliced onions to sandwiches. – A sandwich made with sliced onions adds a nice touch to your meal.
  4. Include onions in soups. – Soups are great because they’re filling and nutritious. You can add as many vegetables as you like to your soup.
  5. Try onion rings. – Onion rings are crispy on the outside and tender on the inside. They’re perfect for dipping in ketchup.
  6. Mix cooked onions with mashed potatoes. – Mashed potatoes are a favorite comfort 

food. Adding onions will give them more flavor.

  1. Chop up onions and use them as garnish. – Chopped onions are a tasty way to decorate food.
  2. Sprinkle chopped onions on top of the pizza. – Pizza is a quick and easy snack. Just sprinkle chopped onions on top of your pizza and enjoy!
  3. Top burgers with chopped onions. – Burgers are a fun treat that everyone loves. Top your burger with chopped onions and serve immediately.
  4. Add chopped onions to pasta. – Pasta is a common side dish. Adding chopped onions gives it a unique taste.

How To Select And Store Onions

Onion varieties vary widely in size, shape, color, flavor, texture, and even nutritional value. Choosing the best onion for you depends on what you plan to use it for. Here are some tips for selecting and storing onions.

Choosing Onions

Selecting onions starts with choosing the type of onion you want. There are many different types of onions, including sweet, red, white, yellow, and green onions. Sweet onions include Vidalia, Walla Walla, and Maui onions. Red onions are another popular choice. They come in a variety of colors, ranging from light pink to deep purple. 

White onions are milder than other types of onions. Yellow onions are usually used in salads. Green onions are often referred to as scallions. These small bulbs grow up to about 2 inches long.

When shopping for onions, look for ones that are firm and free of soft spots. You don’t want to buy onions that are too old because they tend to lose their flavor over time. Also, avoid onions that are wilted or discolored. If you see signs of mold, rot, or insects, do not purchase those onions.


Store onions in a cool, dry place away from sunlight. This helps prevent the growth of bacteria that cause spoilage. Store onions in a plastic bag or container in the refrigerator crisper drawer. Do not store onions near apples or potatoes, since both produce ethylene gas, which causes onions to turn brown.

If you notice any changes in the quality of your onions, discard them immediately. For example, if your onions start to wilt, smell musty, or develop holes, throw them out.

Here are some tips to store onions properly.

1) Wash the onions thoroughly before cutting them into pieces. Remove all dirt and debris by rubbing them under running water.

2) Cut the onions into equal-sized pieces.

3) Place the cut onions in a bowl and cover them with cold water. Soak the onions for at 

least 20 minutes. The longer you soak them, the better they’ll absorb the flavors.

4) Drain the onions well and pat them dry with paper towels.

5) Transfer the onions to a storage container. Refrigerate them right away.

6) Use the onions within 3 days.

Frequently Asked Questions

Is it good to eat onions every day?

Yes, but eat in moderation to avoid heartburn, indigestion, gastric burning, and other side effects mentioned above.

How many times a day should you eat onion?

You can eat onions at any time of the day. Make sure that you don’t eat too much onion in one go. Cooked onion is better than raw onion as it is less likely to cause problems like bad breath, abdominal pain, and intestinal gas.

Can I Eat Raw Onion?

Yes, you can eat raw onion. However, you need to be careful while consuming them because they may irritate your eyes. They are also more likely to cause bad breath and digestive issues like gas and bloating.

What is the best way to cook an onion?

Boil them till soft and then peel off their skin. Then cut into slices and fry them with oil.

Which is healthier: Fried or boiled onions?

answer – Both fried and boiled onions are equally healthy. However, boiling onions will give more flavor than frying them.

How can I tell if my onions are bad?

When you buy fresh onions, look at the color of the outer layer. White onions should be firm and smooth. Yellow ones should be bright yellow and dry. Brownish-yellow ones should be moist. Red ones should be wrinkled. Green ones should be soft and green.

How long does it take to cook onions?

Generally, it takes about 20 minutes to cook onions.

How do you know when onions are done cooking?

You should check whether the onions are soft enough. If they are still hard then continue cooking them. 

Should I cut up or chop up onions before cooking them?

Chop them first and then cook them. This will ensure that all the nutrients get released.

How long does it take for onions to lose their pungency?

It depends upon the type of onions you are using. Some varieties of onions keep their pungency longer than others.

Who should not eat onions

People who suffer from heart disease, kidney failure, stomach ulcers, bleeding disorders, asthma, diabetes, epilepsy, migraine headaches, gallbladder stones, liver disease, intestinal blockage, and those taking blood thinning medications should avoid eating onions.

In some people, diallyl disulfide and lipid transfer protein in onion may cause allergy symptoms like asthma, runny nose, nasal congestion, red eyes, itchy eyes, redness of the skin, itchiness, etc. 

They should also avoid eating or handling onions.

Is there anything wrong with eating too much onion?

Yes. Too much intake of onions can lead to nausea, vomiting, diarrhea, abdominal pain, bloating, heartburn, and IBS symptoms

Is eating raw onion good for you

Yes; In moderation.

Are onions safe to eat during pregnancy?

Yes as long as you eat them in moderation and keep your doctor informed. 

What is the best time to eat onion?

You can eat onions at any time of the day. 

How much onion should I eat a day?

One medium-sized onion is enough for the day.

Is onion better cooked or raw

Eating raw onions is fine but you must remember to wash them thoroughly after peeling.

Don’t eat too much though.

why do onions make us cry?

The tears are caused by the presence of sulfur compounds in onions. These compounds irritate the eye and nose.

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