Shallots are high in antioxidants and may improve blood sugar levels, circulation, seasonal allergies, and heart and bone health. They may also help fight germs and promote weight maintenance. The flavor of a shallot is more delicate, softer, and less abrasive than that of an onion. (Take heed, self-professed onion haters out there.) But the flavor is also a bit deeper, bringing in notes of garlic, which a white or red onion definitely doesn't have.