6 Onion Health Benefits And Why Is Good To Eat It Every Day

April 1, 2022 • By Camila Thomas
The estimated reading time is 10 minutes
onion health benefits

Onion! When it comes to your mind you think how it makes your eyes watery and you probably hate it! But, this vegetable,  а staple for so many cookbooks is so nutrient-packed and so aromatic that putting it into your dishes is a very smart move. It is also very low in calories and thanks to its nutritional value and delicious flavor, most people consume roughly 20 pounds of it per year, no matter if it is raw, cooked, powdered, or pickled. (1)

Onion Benefits And Why Is Good For You

Onion is a vegetable species that belongs to the family genus allium and is similar to aromatic bulbs like garlic, leeks, chives, and shallots. It contains many vitamins, minerals, and many other compounds that are very beneficial and good for your health.

It is one of the oldest cultivated herbs and has been revered for centuries for its therapeutic use. (2)

Onion might have benefits for different aspects of health:

1. It may promote heart health

Onion is rich in antioxidant quercetin, which is anti-inflammatory, and it may prevent some heart disease risk factors such as high blood pressure. In one study, with 70 overweight people, it lowered their blood pressure by 3–6 mmHg. (3)

One other study showed that it could reduce total and  LDL levels if consumed 40–50 grams/day in overweight patients. (4)

2. It has anti-cancer properties

Scientists do not fully understand how its compounds fight cancer, but they presume that they inhibit cell mutation and tumors.

It is probably linked to flavonoid antioxidants and sulfur compounds that can be found in almost all allium vegetables. Onion is rich in onions A, a sulfur compound that impairs cancer development. ( 5)

3. It has antibacterial properties

It has been known as a home remedy for centuries. Everyone knows that placing it in a room will absorb all the bacteria and viruses.

One study confirmed that it could fight dangerous bacteria such as  Staphylococcus aureus (S. aureus)  Escherichia coli (E. coli),  and Bacillus cereus. (6)

Quercetin taken out from yellow onion skin successfully prevented the growth of Helicobacter pylori (H. pylori). (7)

4. Onions are rich in prebiotics

Onions are rich in prebiotics and fiber that promote gut health and boost immunity. They also increase probiotics such as Lactobacillus and bifidobacteria strains which are very important for digestive health. (8)

5. It supports bone health

Although dairy products are known to boost bone health, onions may fight osteoporosis and the thinning of the bones that come with age.

In one study, 507 women in the perimenopausal and postmenopausal phase who ate onions at least once per day had a greater bone density compared to those who did not eat them. (9)

It may also increase your body's antioxidant levels. (10)

6. It is anti-inflammatory and can fight inflammation

Onions are packed with antioxidants that can repair and protect the damaged cells in your body and are one of the best sources of flavonoids. (11)

According to studies, yellow onions are richer in antioxidants than other types of onions. Diet rich in onions can reduce inflammation and reverse the free–radical damage that leads to stronger immunity.

Onion's Nutritional Value

Onions are very low in calories and 100 gr. of onions, there are only 30 calories.

They are mostly composed of water ( 89 % ). The rest goes to 9 % of carbohydrates, 1,7 % fiber, and tiny amounts of fat and protein.

The main nutrients in 3.5 ounces (100 grams) of raw onions are

Calories: 40

  • Water: 89%
  • Protein: 1.1 gr
  • Carbs: 9.3 gr
  • Sugar: 4.2 gr
  • Fiber: 1.7 gr
  • Fat: 0.1 gr

Why Is It Good To Eat Onions Every Day? 

They were used as a medical remedy even by the Ancient Romans and Greeks and Romans believed that it would impact their strength and were often consumed by gladiators. This doesn't come with a surprise as onions are packed with vitamins and nutrients like:

  • Manganese
  • B vitamins ( including folate and B6)
  • Vitamin C ( boosts immune system and iron absorption)
  • Biotin
  • Copper
  • Potassium
  • Selenium

As mentioned, they have endless benefits for your health, including heart and bone health and may fight bacteria like E. coli, S. aureus, and Bacillus cereus. Rich in prebiotics and fiber they are very beneficial for your digestion and are a great food to eat daily.

Still, if you suffer from heartburn or take blood thinners, you should not consume them in high doses as it may worsen the symptoms and have negative effects on these medications.

Eating Raw Onion Is Good For Your Health

It can be found in almost any salads made by our mammies and grannies and we cannot deny the fact that they would not be so delicious without onion.

To get the most benefit from it, it's best to eat it raw. Cooking them for longer than 30 minutes may partially destroy their sulfur compounds. 

We already mentioned some of its benefits for your overall health, but they can also be very beneficial for:

Oral Health

Although it might give you some bad breath and you may avoid it, onion is good for oral hygiene as it is rich in vitamin C and in antimicrobial sulfur compounds that can diminish the bacteria in your mouth.

It Can Promote Eye Health

Onions are rich in selenium which helps in the production of vitamin E which helps fight conjunctivitis. They also contain glutathione, a sulfur protein that acts as an antioxidant for the eye's lens and prevents glaucoma and cataracts.

Sexual Benefits Of Drinking Onion Water

Onions are potent aphrodisiacs and may increase the testosterone production in the body and increase the sperm amount for managing the man's infertility. They have been used throughout history to treat hypoactive sexual desire. In Ayurveda, onions are known for building sexual energy.

One study showed that onion water could increase testosterone production in rats and some other benefits for man's health. (12)

How Should You Take It?

You should mix 3 tbsp of onion juice with ginger powder and take it daily. It will considerably boost your libido.

You can even make a mixture of onion juice, ginger, and garlic. They are all potent aphrodisiacs since both garlic and onion contain a powerful compound called allicin.

Red Onion Juice For Hair

Onion is rich in minerals that are good for your hair. One study showed that applying it to your scalp might help hair regrow in some people. The hair started regrowing after two weeks of using onion juice that was applied twice per day. (13)

Onion Juice For Weight Loss

Onions are fat-free and packed with antioxidants that can help with metabolism and weight loss. Some nutritionists advise taking it on an empty stomach with honey to get rid of some extra fat accumulated in the stomach.

Onion Juice Recipe For Weight Loss:

  • Chop the Onion
  • Blend it with some water
  • Add  1 tablespoon honey and drink it on an empty stomach every morning 

Onion Juice For Strong Immunity

They are rich in vitamin C and zinc and phytochemicals and are great immunity boosters you can prepare a simple drink to help you with rebuilding your defense mechanism against viruses.

  • Take one peeled and chopped onion and put it in a glass of water.
  • Put it to soak in it overnight.
  • Take a few sips of it in the morning and continue to take a few sips during the day with breaks in one to two hours.

Fried Onion Health Benefits

Deep-fried onion rings are a very popular appetizer. They are very easy to prepare, and you need only two ingredients: onions and bread. They are usually deep-fried in vegetable oil in most cases. That is why a 100 gr serving contains 411 calories. 

But, they can still serve your health and you will get 10 % of the daily requirement of vitamin B6, manganese and vitamin C. Onions also contain powerful antioxidants and can boost your immunity.

When combined with turmeric, they may have anti-cancer properties. One study in 2007 confirmed that its antioxidant, quercetin, may reduce high blood pressure in adults.

Still, deep-fried rings are not as healthy as raw onions. They contain trans- fat that can provoke heart disease, strokes, and high cholesterol levels.

So, it is advisable to bake them instead of frying them or simply frying them in an air fryer to reduce the calories.

You can also use a healthy oil like coconut, avocado, sesame, or olive oil to fry them. Avoid putting ketchup or other condiments high in sugar to reduce the carbs.

Garlic Versus Onion Health Benefits 

Garlic and onion make a difference in nutrients as follows:

  • Garlic is richer in thiamin, riboflavin, niacin, pantothenic acid, and Vitamin B6. But, onion contains more folate.
  • Garlic is richer in iron than onion.
  • Garlic is richer in dietary fiber
  • Garlic is richer in calcium and potassium
  • Garlic is richer in calories and proteins but lighter in carbs.
  • They are similar to fat
  • Garlic is much richer in Vitamin C and garlic has 31.2mg, while onion has 7.4mg of Vitamin C, but they contain similar amounts of vitamin K

They both have anti-cancer properties and almost all allum vegetables are related to decreased risk of cancer.

Both are good for promoting heart health with their anti-inflammatory properties and high – antioxidant content. (14)  (15)

They have both antimicrobial properties and fight bacteria and viruses. (16)

Health Benefits Of Onion And Honey

Onions and honey are superfoods that can be very beneficial when combined. They have been known as alternative  and home remedies for centuries and can be used for the following medical conditions:

  • Wounds and skin burns – when applied, it has healing properties as both have antibacterial properties
  • Both boost fertility – both are rich in vitamins and antioxidants that can be beneficial for sexual health and fertility
  • Both  may promote hair growth – when combined, they improve blood circulation and this leads to hair growth
  • Protect against cancer – both rich in vitamin C fight against toxins and pollutants that may damage the cell function.
  • Promote weight loss and burn belly fat – you should take onion juice with honey on an empty stomach in the morning. The antioxidant quercetin boosts the metabolism and prevents the accumulation of fat.
  • It is a great folk remedy against cold – both have antibacterial properties and inhibit bacteria growth. They are both known as natural antibiotics.
  • Onion and honey can be also be used for fighting dandruff and for clearing acne and skin regeneration. Onion is rich in vitamin C and can help your skin look young.

Onion Side Effects

1. It can irritate the eyes

You probably have experienced the burning sensation in your eyes when you chop the onions.

It has a compound called LF that is very volatile, and when it reaches your eyes, it causes the tearing effect. To prevent this, you can chop the onion under running water, wear goggles, or cool it in the fridge before chopping it.

2. It can increase the heartburn effect

One study confirmed that it could increase heartburn episodes in people who suffered from this condition. (17)

3. Bad breath

You already know that you may experience bad breath after eating a dish that contains onions.

4. Drug interaction

Onion has a potential anticoagulant effect, may prevent blood clot formation, and can interact with certain medications such as warfarin and increase the risk of bleeding a little bit.

5. It can cause bloating

People with irritable bowel syndrome and those with sensible digestive tract may find it hard to digest and can cause cramps, bloating, and painful gas due to fibers called fructans.


Onion is a vegetable species that belongs to the family genus allium and similar aromatic bulbs like garlic, leeks, chives, and shallots. It contains many vitamins, minerals, and many other compounds that are very beneficial and good for your health.

Rich in prebiotics and fiber they are very beneficial for your digestion and are a great food to eat daily. Still, if you suffer from heartburn or take blood thinners, you should not consume them in high doses as it may worsen the symptoms and have negative effects on these medications.


Camila Thomas

Camila Thomas enjoys writing about physical and mental health, nutrition, fitness, and lifestyle. Her main goal is to educate, inform, and inspire readers globally to think and act. She inspires them to act and educate them on nutrition and healthy living using real and scientifically-based facts that support her ideas.
This content is only for educational and informational purposes. It should not be considered as medical advice or taken as a treatment instead of one from a licensed physician. All readers should consult their doctors or certified health professionals before taking any advice from this site and applying it to their condition. We do not take responsibility for possible health issues of any person following the content in this informational website. All the viewers of this site should consult their physicians or doctors before taking on any supplement, diet, nutrition, or lifestyle program.
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