*What Else?* Onions is amint the best source of quercetins, which are phytonutrients found in certain plants. Quercetins are: - Beneficial for cardiovascular health, including raising good cholesterol and lowering high blood pressure; - Powerful anti-cancer and cancer prevention agents; - Immunomodulators that support immune functions. So have an omelette and garlic water every now and then.