Nutritious Value of Red Onions

Because red onions are not as pungent, you can eat them raw.
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Onions have more value than ruining your breath. These vegetables add flavor to your favorite recipes and provide you with essential nutrients. The different types of onions are all very similar but vary slightly in terms of flavor or texture. Red onions have a deep purple outer layer. They have a milder flavor than other onions, perfect to eat raw in salads or on sandwiches. Although all onions are healthy, red onions have higher concentrations of antioxidants than other types of onions.

Calories, Carbohydrates and Fat

Red onions, like other types of onions, are very low in calories and carbohydrates. A 1/4-cup serving of red onions contains 15 calories. The same serving size has 3 grams of carbohydrates, or 1 percent of your daily value. Red onions are also a relatively good source of dietary fiber with 1 gram, or 4 percent of your daily value, in a 1/4-cup serving. Red onions do not contain any fat.

Vitamins and Minerals

All types of onions, including red onions, are a good source of several vitamins and minerals. A 1-cup serving of onions has 12 milligrams of vitamin C, or 20 percent of your daily value. The same serving has 0.2 milligram of vitamin B-6, which is 10 percent of your daily value. Onions are also a good source of folate, manganese, phosphorus and potassium, containing 5 percent or higher of the recommended daily intake of these essential nutrients.


Red onions are a good source of flavonoids, a type of phytonutrient that may help to prevent or fight against disease. Onions are one of the richest sources of flavonoids in the human diet. Flavonoid consumption may help to prevent cancer, heart disease and diabetes. Flavonoids also have anti-bacterial, anti-viral, anti-allergenic and anti-inflammatory properties. Specifically, red onions are higher in quercetin, a specific type of flavonoid, than other types of onions or garlic, according to research published in the “Journal of Agriculture and Food Chemistry.”


Add red onions to your daily diet to receive the most health benefits. You can include red onions in salads, soups, sauces, on sandwiches or on flatbread pizzas. Choose red onions that have a dry outer layer and no signs of decay. When using red onions, keep as much of the outer layer as possible because that contains the majority of flavonoids. Store red onions in a well-ventilated area, away from heat and light.

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