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Onion, red onion Calories and nutrition facts · Vegetables

37 kcal per medium (110 g)
Carbs
6 g
Fibre
2.2 g
Sugars
3.9 g
Protein
1.7 g
Fat
0.13 g
34 kcal per 100 g
Carbs
5.4 g
Fibre
2 g
Sugars
3.6 g
Protein
1.5 g
Fat
0.11 g

Where the calories come from

Protein 21% Carbs 76% Fat 4%

Onion, red onion has 37 kcal per medium (110 g), with 6 g carbs, 2.2 g fibre, 1.7 g protein and 0.13 g fat. 100 g has 34 kcal.

Share of your daily needs in one medium

Diet tags

Cholesterol reduced Egg free Gluten free Lacto-ovo vegetarian Lactose free Lacto vegetarian Milk free Low gluten Soy free Unsweetened Vegan

Last updated June 30, 2026 · Where the data comes from

Get to know onion, red onion in Nutriely

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How it compares with other vegetables

Per 100 g, against the 97 vegetables in our catalog.

  • Calories 34 kcal · typical 30 kcal
  • Vitamin K 0.7 µg · typical 40 µg

    Less vitamin K than 89% of vegetables.

  • Vitamin C 5.3 mg · typical 21.8 mg

    Less vitamin C than 80% of vegetables.

  • Folate 27.1 µg · typical 51.3 µg
  • Vitamin A 0.57 µg · typical 50 µg

    Less vitamin A than 89% of vegetables.

  • Potassium 220 mg · typical 350 mg

    Less potassium than 87% of vegetables.

The bar shows this food; the line marks the typical (median) value of the category.

Learn about onion, red onion

What are the health benefits of onions and red onions?

Onions and red onions are rich in antioxidants, particularly quercetin, which may help reduce inflammation and lower the risk of chronic diseases such as heart disease and certain types of cancer. They also contain vitamins C and B6, which support overall immunity and the nervous system, and are a good source of fiber, which aids in digestion and may contribute to a healthy gut microbiome.

Are there any health risks associated with red onions?

Red onions are generally safe to eat and provide numerous health benefits. However, some individuals may experience digestive discomfort or heartburn after consuming them, especially if they are sensitive to high-FODMAP foods. Additionally, allergies to onions are possible, although they are relatively uncommon. If you have concerns about consuming red onions, it's best to consult with a healthcare professional.

Nutrients in onion, red onion

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Minerals
Carbohydrates
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Amino acids

Amino acid data is mapped from the USDA database, for information only.

Similar vegetables

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Where the data comes from

How we combine and check nutrition data: Nutriely data sources.

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