You don't need expensive foods to support your heart health. Red onions contain quercetin, a naturally occurring antioxidant that has been studied for its potential cardiovascular benefits. Some human studies involving concentrated onion extracts or quercetin supplements have reported improvements in LDL cholesterol, although results vary and cannot automatically be applied to eating ordinary red onions. Adding red onions to salads, sandwiches, and other meals is a simple way to enjoy more vegetables and beneficial plant compounds.
