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Onion Nutrition Facts: A Detailed Analysis

Onions, a versatile and flavorful vegetable used in various culinary dishes worldwide, possess an impressive nutritional profile. In this article, we will delve into the comprehensive nutritional breakdown of onions, exploring their macronutrients, micronutrients, antioxidants, and minerals, shedding light on their health benefits and how they contribute to a balanced diet.

Macronutrients in Onions

Onions are low in calories, making them a suitable addition to weight-conscious diets. In a 100-gram serving of raw onions, you can expect to find approximately 40 calories. The majority of these calories come from carbohydrates, with about 9 grams per 100 grams of onions. Dietary fiber, an essential component of a healthy diet, constitutes around 1.7 grams per 100 grams of onions. Fiber aids in digestion, helps regulate blood sugar levels, and promotes satiety.

Micronutrients in Onions

Apart from macronutrients, onions boast an array of essential micronutrients that are crucial for overall health. These include:

1. Vitamin C (Ascorbic Acid)

Onions are rich in vitamin C, an antioxidant that supports the immune system, aids in collagen production, and protects cells from damage caused by free radicals. In 100 grams of onions, you can find approximately 7.4 milligrams of vitamin C, which contributes to around 8% of the Recommended Daily Allowance (RDA).

2. Vitamin B6 (Pyridoxine)

Vitamin B6 is vital for various physiological processes, such as metabolism, nervous system function, and the production of neurotransmitters. A 100-gram serving of onions contains approximately 0.12 milligrams of vitamin B6, contributing to around 9% of the RDA.

3. Folate (Vitamin B9)

Folate plays a crucial role in DNA synthesis and repair, making it especially important during periods of rapid cell division and growth, such as pregnancy. Onions provide approximately 19 micrograms of folate per 100 grams, accounting for around 5% of the RDA.

4. Potassium

Potassium is an essential mineral that helps maintain fluid balance, nerve function, and muscle contractions. In 100 grams of onions, you'll find approximately 146 milligrams of potassium, contributing to around 3% of the RDA.

5. Phosphorus

Phosphorus is necessary for bone health, energy production, and DNA synthesis. A 100-gram serving of onions contains approximately 29 milligrams of phosphorus, contributing to around 4% of the RDA.

Antioxidants in Onions

Onions are a rich source of various antioxidants, which play a crucial role in neutralizing harmful free radicals in the body. Some of the key antioxidants found in onions include:

1. Quercetin

Quercetin is a powerful flavonoid with anti-inflammatory properties. It helps combat oxidative stress and reduces the risk of chronic diseases such as heart disease and certain cancers. Onions offer approximately 19 milligrams of quercetin per 100 grams.

2. Anthocyanins

Anthocyanins give red and purple onions their vibrant color. These compounds possess antioxidant and anti-inflammatory effects, promoting heart health and overall well-being.

Minerals in Onions

In addition to the micronutrients mentioned earlier, onions contain various minerals that are essential for maintaining good health. These include:

1. Calcium

Calcium is crucial for bone health, muscle function, and nerve transmission. Onions provide approximately 23 milligrams of calcium per 100 grams.

2. Iron

Iron is necessary for oxygen transport in the body and plays a central role in red blood cell production. In 100 grams of onions, you'll find approximately 0.21 milligrams of iron.

3. Magnesium

Magnesium is involved in hundreds of biochemical reactions in the body, supporting muscle and nerve function, regulating blood pressure, and maintaining bone health. Onions offer around 10 milligrams of magnesium per 100 grams.

4. Zinc

Zinc is essential for a healthy immune system, wound healing, and DNA synthesis. A 100-gram serving of onions contains approximately 0.17 milligrams of zinc.


In conclusion, onions are not only a flavorful addition to meals but also a highly nutritious vegetable. From macronutrients like carbohydrates and dietary fiber to an array of essential micronutrients, antioxidants, and minerals, onions offer a host of health benefits. Including onions in your diet can contribute to improved immunity, better bone health, and reduced risk of chronic diseases. So, the next time you sauté onions for your favorite dish, remember that you're not just adding flavor but also nourishing your body with valuable nutrients.

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