✓ Evidence Based

8 Proven Health Benefits of Onion

Onions are one of the healthiest and most nutrient-dense vegetables that anyone can enjoy. There are many different types of onions for many recipes.

Between white, red, yellow, and green onions, there are various options and ways to add more onions to your diet.

Enjoy onions raw, cooked, or just chopped into your favorite meal for an easy extra serving of healthy vegetables.
Onions have sulfur-containing amino acids, which is great for the body in many ways (1). They also have tons of vitamins and minerals optimal for everyday health (2). There are numerous ways onions can benefit your body.

Did You Know?:Historians estimate that onions have been grown and used for at least 5,000 years.

Health Benefits of Onion

So why eat more onions in your daily routine? There are many other reasons why adding more onions to your diet can improve your health.

Check out the information below to see the health benefits of onions, along with the potential risks. Plus, find out how to start adding more onions to your diet.

1. They May Improve Brain Health

Onions can improve the health of many organs in the body, but did you know onions can even enhance brain health?

These vegetables are exceedingly healthy for brain health in regards to concentration, memory, and more. That is because onions are high in essential vitamins and minerals like vitamin C, B vitamins, potassium, and more (3). Onions suppress inflammatory pathways in the brain, which can even help to decrease the risk of Alzheimer’s disease (4).

To get a brain boost and enhance cognitive performance, try adding more onions to your diet. Although more research is necessary to support onions as a preventative for Alzheimer’s disease, there is some evidence it can help.

See if adding more onions to your diet helps improve your concentration, memory, and perhaps beyond.

Summary:Onions may improve brain health and has anti-inflammatory properties that suggest it as a possible preventative for Alzheimer’s disease.

2. They Can Help Support Bodily Functions

Onions are high in sulfur-containing amino acids, which can help to support metabolism of the liver and kidneys. Onions contain quercetin, which is a type of antioxidant that prevents free radicals and harmful cells from being in the body (5).

When cut, there are chemical compounds in onions that release, which is why onions are famous for making you cry (6).

Some signs you may need a cleanse is you are suffering from constipation, brain fog, or even more food sensitivities. Perhaps just adding some more of this potent vegetable to a healthy and nutritious diet is all you need.

Try to make sure you keep a healthy diet and lifestyle to help ensure the organ systems in your body are functioning well.

Summary:Onions contain quercetin, which is an antioxidant that helps support bodily functions especially in the liver. Quercetin also helps to reduce the number of free radicals in the body.

3. They May Improve Digestion

Did you know that onions can even improve digestion? To have optimal digestion, you must eat a healthy diet full of nutrient-dense foods, and onions can be a helpful addition to that diet.

Onions can help improve digestion because, on top of being high in many nutrients, they are also high in fiber (7). Fiber is essential for healthy digestion because it increases the size of bowel movements, allowing for easier digestion (8).

Try to add more onions to your diet to assist with your digestion, along with a lifestyle of healthy habits. Onions can even help to alleviate stomach distress but be cautious of how onions affect you. High intake can cause stomach distress for some (9).

Summary:Onions are high in nutrients like fiber, which help support a healthy digestive system and may improve digestion.

4. They Can Improve Heart Health

Heart disease and heart issues are the most common chronic disease and disorders in the United States. Heart disease is the number one killer, and most cases are entirely preventable.

A healthy diet and healthy habits can help with proper blood flow, which is necessary to maintain a healthy heart, muscles that make up the circulatory system.

In one study in the National Institutes of Health (NIH), garlic and onion showed an improvement in cardiovascular health (10) (11).

Do not be afraid to add more onions to your next meal so they can help boost the health of your heart.

Summary:Studies have shown that eating vegetables like garlic and onion showed an improvement in heart health.

5. They May Help Fight Viruses

Onions are full of potent antiviral compounds, so many believe in their use to help fight off colds and viruses. On top of antiviral compounds, onions also have tons of essential vitamins and minerals that can help fight viruses faster.

You can try adding onions to make your soup or tea to reap the many health benefits when you get a cold. Eating more nutrient-dense foods, in general, can help to ward off viruses like the common cold, and maintaining a healthy diet can keep them away longer.

See if adding onion to your routine helps to fight off viruses faster and even prevent them in the future.

Summary:Onions contain antiviral properties that may help ward off certain colds and viruses.

6. They Can Fight off Harmful Bacteria

Onions have potent antiviral and antibacterial properties, and they can even help fight off harmful bacteria caused by E. coli, Streptococcus mutans, and more.

Onion extracts appear to have some effect on decreasing harmful bacterial strains such as S. mutans JC-2, S. sobrinus OMZ176, P. gingivalis ATCC 33277, and P. intermedia ATCC 25611 (12).

Onions can be a potent addition to your routine when bacteria come up. Although more research is necessary to support this, adding onions to your diet during bacterial infections along doctor-recommended prescriptions can help.

Summary:Onions have been shown to decrease negative effects of harmful types of certain strains of bacteria.

7. They May Improve Bone Health

Onions may even help to improve bone density, with the possibility of preventing osteoporosis. These vegetables can be helpful in women going through menopause in the perimenopausal stages as well (13).

That is because onions are high in flavonoids like quercetin that help to promote bone health (14).

They protect bones from free-radical damage, increasing bone density for many (15).

Summary:Studies have suggested that eating onions may help to promote bone health and increase bone density due to the nutrients they contain.

8. They May Enhance the Immune System

Adding new foods like onions can further help to enhance your immune system.

Onions can help to boost your immunity due to their high vitamins, mineral, and antioxidant profiles (16). They are high in vitamin C, which is essential at rebuilding cells and keeping your immune system functioning well (17).

This versatile vegetable is well-known for its health benefits, and it can still be a helpful solution to enhance your immune system, along with a healthy diet and lifestyle (18).

Summary:Onions contain several vitamins and minerals which can help boost your immune system and health.

Where Can You Add More Onions to Your Diet?

There are many ways to eat more onions, even for the onion-haters out there. You can cut onion small in dishes if family members do not enjoy the texture. You can also change up the flavor a bit by adding lemon to red onions.

Look at the list below to see where to add in more onion today.

Add more onions to your diet by:

  • Add scallions to eggs, stir-fries, and more
  • Cook with white or yellow onions
  • Add red onions to lemon juice for a pickled-onion type flavor to many meals, such as seafood
  • Add white or yellow onion to hot water with ginger for a cold-busting soup

You can easily reap the many health benefits of the onion by adding it to many meals you already make at home. Where can you start adding more onions to reap the benefits of your meals this week?

Summary:There are tons of ways to add onions to meals as they can be eaten raw or cooked.

Are There Any Side Effects to Eating Onions?

Onions typically do not pose much of a risk for most people. They are a healthy addition to most diets, especially when eaten in small amounts.

However, there are some health risks for those who suffer from certain conditions:

Some rare side effects of too much onion include (19):

  • Bloating
  • Gas
  • Stomach distress
  • Skin irritations

Overall, eating onions is a healthy part of a nutritious diet that can help ward off illness and keep you well (20).

If you suffer from a disease or disorder that makes it difficult for you to eat onions, or if eating onions is bothersome, speak with your healthcare professional about it. You may have an allergy or sensitivity to onions.

Summary:There are minimal to no side effects to eating onions. However, some people with certain health risks may experience side effects from eating onions.


There are many health benefits of adding onions to your diet more often. From improving digestion to boosting the immune system, and more, onions can be a helpful vegetable to keep around.

Using onions in food is generally safe for most people. There is typically no need to worry about overdoing it with onions.

Onions can significantly help increase your health over time. Always do what is right for your body and monitor how certain vegetables react with your body.