Stock up on breath mints, because the benefits of garlic and onions are worth the pungent aromas they leave behind when you eat them. Onions and garlic have components that act as antioxidants to prevent cell damage, and they're anti-inflammatory agents that may reduce swelling and pain in your body. Onions are among the best natural sources of quercetin, a substance that some research shows may reduce inflammation in heart cells, lowering your risk for heart disease. Quercetin may also help with certain pain conditions including chronic pelvic pain and, in men, prostatitis. Garlic contains sulfur compounds that have both anti-inflammatory and anti-arthritic effects in the body. "Include garlic and onions as part of your daily diet and over the long-term you are likely to reap the pain and inflammation-fighting benefits of these foods," Arjmandi says.