Nutrients in a Purple Onion

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Purple onions have more soluble than insoluble fiber. Soluble fiber attracts fluid in your gut, creating a slow-moving gel. This slows digestion, which allows vitamins and minerals to absorb through intestinal walls. Insoluble fiber from the skins of onions sweeps out your gut like a broom and helps you have regular bowel movements…

A 1/2-cup serving of julienned purple onions provides approximately 65 calories…  Purple onions have about 1 gram of protein, which also contains 4 calories per gram…

Purple onions are particularly rich in flavonoids called anthocyanins. These types of phytochemical compounds neutralize free radicals that scavenge through your system destroying healthy cells and tissues. Flavonoids protect vital organs, including your heart, and help lower your risk of cancer. There is not a set recommended amount of flavonoids you need in your diet, but eating a variety of colored fruits and vegetables ensures that you get plenty of these beneficial compounds.

Vitamin C boosts your immune system. This vitamin also helps build collagen, a component of skin that is essential for elasticity and wound healing. Vitamin C acts like an antioxidant and works alongside flavonoids to diminish free radicals. Women require 75 milligrams of vitamin C every day, but men need 90 milligrams, the Linus Pauling Institute reports. You can get about 12 milligrams of vitamin C from a 1/2-cup serving of raw, purple onions.