Onions are high in vitamin C, which may help regulate your immune health, collagen production, and iron absorption. It's also a powerful antioxidant that could help protect your cells from unstable, damaging molecules called free radicals. Onions are rich in B vitamins, including folate and vitamin B6.

They're high in antioxidants and sulfur-containing compounds, some of which may have a number of beneficial effects. Although more research is needed, onions have been linked to improved bone health, lower blood sugar levels, and a reduced risk of cancer.