Nutrition for Onion

Calories, Protein, Vitamins and More

image of onion source

Onion Nutrition Summary

One onion (150 grams or 0.3 lb) contains 60 calories and 1.7 grams of protein. Onion consist of 89% water, 9% carbohydrates, 1% protein, and less than 1% of fat.

Onion is an excellent source of a few nutrients, including dietary fiber and potassium. It also contains significant amounts of Vitamin C, calcium, Vitamin B6 and manganese.

In one onion:

  • Calories: 60
  • Protein: 1.7 g
  • Sugar: 6.4 g
  • Dietary fiber: 2.6 g
  • Fat: 0.2 g, (Saturated: 0.1 g)
  • Sodium: 6 mg
There is no significant amounts of cholesterol in onion.

See the Onion Nutrition Chart for complete recommended daily values.
The specific nutritional values from USDA is for: Onions, raw.

Calories in Onion

Onion has 60 calories per onion or 40 calories for every 100 grams. Most of its calories are from carbohydrates and protein.

87% of calories in onion are from carbohydrates, 11% of calories are from protein and 3% of calories are from fat.

Calories from Carbs

The majority, or 87% of the calories in onion are from carbohydrates. The carbs in onion are mostly in the form of dietary fiber and sugar (29% and 71%). 1 onion has 10% of daily values or 2.6 grams of dietary fiber.

  • Dietary fiber: 2.6 g
  • Sugar: 6.4 g
There is no significant amounts of starch in onion.

Calories from Fat

A small portion, or 3% the calories in Onion are from fat. Onion is very low in total fat, with 0.2 grams per onion. Most of the fat in onion are healthier unsaturated fats.

Onion is cholesterol free and trans-fat free.

  • Total fat: 0.2 g
  • Saturated fat: 0.1 g
There is no significant amounts of cholesterol, trans fat, monounsaturated fat or polyunsaturated fat in onion.

Calories Similar to Onion

Some other vegetables with similar calories to onion by weight:

Protein in Onion

One onion has 1.7 grams of protein or about 3% of daily recommended intake. Onion is relatively low in protein, and is not a source of complete protein, containing little or small amounts of the majority of the nine essential amino acids.

  • Protein: 1.65 g
  • Threonine: 0.03 g
  • Leucine: 0.04 g
  • Lysine: 0.06 g
  • Phenylalanine: 0.04 g
  • Valine: 0.03 g
There is no significant amounts of tryptophan, isoleucine, methionine or histidine in onion.

Protein Similar to Onion

Some other vegetables with similar amounts of protein to onion by weight:

Vitamins and Minerals in Onion

An good source of nutrients, onion contains abundant amounts of potassium. In fact, a single onion contains 10% of recommended daily values or 219 milligrams of potassium.

Vitamins in onion (1 large):
  • Vitamin a: 0.9 ug
  • Thiamin: 0.1 mg
  • Niacin: 0.2 mg
  • Vitamin b6: 0.2 mg
  • Vitamin c: 11.1 mg
  • Folate: 28.5 ug
  • Vitamin k: 0.6 ug
Minerals in onion (1 large):
  • Calcium: 34.5 mg
  • Potassium: 219 mg
  • Iron: 0.3 mg
  • Magnesium: 15 mg
  • Zinc: 0.3 mg
  • Selenium: 0.8 ug
  • Phosphorus: 43.5 mg
  • Copper: 0.1 mg
  • Manganese: 0.2 mg
  • Choline: 9.2 mg
There is no significant amounts of riboflavin, pantothenic acid, vitamin e or vitamin b12 in onion.

Similar to Onion for Potassium

Here are some other vegetables with similarly abundant amounts of potassium to onion:

Flavonoids and Carotenoids in Onion [3]

Onion contains a couple of healthy phytonutrients and antioxidants, specifically flavonoid isorhamnetin, kaempferol and quercetin. In one onion:

  • isorhamnetin: 7.52 mg
  • kaempferol: 0.98 mg
  • Quercetin: 30.45 mg

Onion Nutrition Chart


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Nutrition calculations are from Harvard Medical's nutrient guidelines [1] and USDA's food central database (2019) [2].
We calculated values from 2000 kCal daily recommended diet.

Onion in Cooking

Onion is in the top 10 most popular ingredients for recipes. Onion can be consumed raw and is often chopped, sliced or minced before cooking or serving. Most recipes call for one or two onions.

Friends and Relatives of Onion

Foods commonly cooked with onion: Other similar relatives:

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