Onions are highly nutritious vegetables that may have several benefits, including improved heart health, better blood sugar regulation, and increased bone density.

Onions are members of the Allium genus of flowering plants, which also includes garlic, shallots, and leeks.

They’re delicious, versatile, and relatively cheap, and they boast a wide range of healthy vitamins, minerals, and plant compounds.

Read on to discover the possible health benefits of onions and ways to add onion to your diet.

Onions are nutrient dense. They’re low in calories but high in vitamins, fiber, and minerals.

One medium onion, or an onion weighing 110 grams (g)Trusted Source, contains the following:

  • Calories: 44
  • Protein: 1.2 g
  • Carbs: 10.3 g
  • Sugar: 4.66 g
  • Fiber: 1.87 g
  • Fat: 0.1 g
  • Potassium: 161 milligrams (mg)
  • Vitamin C: 8.14 mg

Onions are high in vitamin C, which may helpTrusted Source support immune function, aid in collagen production, and assist in iron absorption.

Onions also contain B vitamins, including folate and vitamin B6. These play key rolesTrusted Source in metabolism, red blood cell production, and nerve function.

Onions also contain potassium, a mineral that may help withTrusted Source:

  • cellular function
  • fluid balance
  • nerve transmission
  • kidney function
  • muscle contraction

Onions contain antioxidants and compounds that may reduce your riskTrusted Source of heart disease.

They contain quercetin, a flavonoid antioxidant and anti-inflammatory that may help Trusted SourcelowerTrusted Source high blood pressure.

However, studies showing that it may help with blood pressure were test tube and animal studies. More research is necessary to better understand the possible benefits of onions on heart health.

Onions are an excellent source of antioxidants and contain at least 17 typesTrusted Source of flavonoids, including anthocyanins.

The authors of a 2019 reviewTrusted Source concluded that consuming more anthocyanin-rich foods was associated with a lower risk of heart disease and of death from heart disease.

Anthocyanins in onions may offer anticancer properties.

Onions also contain fisetinTrusted Source and quercetinTrusted Source, which are flavonoid antioxidants that may inhibit tumor growth.

More research is necessary.

Eating onions may help regulate blood sugar levels.

A 2020 studyTrusted Source showed that rats with diabetes who ate food containing 5% dried onion powder for 8 weeks had decreased fasting blood sugar levels and lower triglyceride and cholesterol levels than a control group.

In animal studies, quercetin has also been shown to decrease:

  • blood glucose
  • liver glucose content
  • enzyme levels
  • serum cholesterol levels

Onions may help support strong bones.

A 2024 studyTrusted Source found that consuming onion flavonoid extract helped increase bone mineral density in rats with osteoporosis. Studies in humans are necessary to further explore this.

Onions may help reduce oxidative stress, boost antioxidant levels, and decrease bone loss. This may help preventTrusted Source osteoporosis and improve bone density.

Onions may help fight potentially dangerous bacteria, such as:

  • Escherichia coli (E. coli)
  • Pseudomonas aeruginosa
  • Staphylococcus aureus (S. aureus)
  • Bacillus cereus

A 2022 reviewTrusted Source suggests that quercetin in onion could inhibit the growth of several strains of bacteria, including Helicobacter pylori, which is associated with stomach ulcers and certain digestive cancers.

A 2018 test-tube study found that quercetin damaged the cell walls and membranes of E. coli and S. aureus.

Onions are a rich sourceTrusted Source of prebiotics, which are necessary for optimal gut health.

Prebiotics are nondigestible types of fiber that are broken down by beneficial gut bacteria.

Gut bacteria feed on prebiotics and create short-chain fatty acids, which may helpTrusted Source:

  • strengthen gut health
  • boost immunity
  • reduce inflammation
  • enhance digestion

Consuming prebiotic foods may also help increase probiotics, such as Lactobacillus and Bifidobacterium strains, which benefit digestive healthTrusted Source.

Onions contains the prebiotics inulin and fructooligosaccharides, which may help increase the number of friendly bacteria in your gut and improve immune function.

Onions are a fresh and versatile staple in kitchens around the world. You can cook them, eat them fried or raw, and more.

To incorporate onions into your diet, you can try:

  • using them in soups such as French onion soup
  • using them in dips and spreads such as guacamole, salsa, and ranch
  • adding them to egg dishes such as omelets, frittatas, and quiches
  • making cooked toppings, such as caramelized onions, to top meat or tofu, or add to savory baked goods
  • using them raw as a topping for tacos or fajitas
  • adding them to salads
  • using them in stir-fries, pasta sauces, or curries

Onions are nutrient-packed vegetables that contain powerful compounds. They have antibacterial properties and promote digestive health, which may improve immune function.

While more research is necessary, onions may also offer possible health benefits such as lowering the risk of heart conditions and cancer.

Onions are easy to add to the diet. You may choose to add them to soups or salads, use them as toppings for tacos or fajitas, or mix them into a dip or spread.