Onion
Many ancient cultures believed in the healing and preventative powers of onions. Even ancient Greek athletes used them prior to competing. Over the years, a number of these age old theories have been put to the test, and more often than not they’re proven true. The sulfur compounds in onions can reduce the symptoms of diabetes, and they’re loaded with quercetin too, which prevents inflammation and helps prevent a number of different cancers.

Cayenne Pepper
Used for anything from pain relief to aphrodisiacs, cayenne peppers have been a staple of the “new world” since Columbus brought them here. These peppers get their heat from capsaicin, and that’s also where the pain relief aspect comes in. Studies have shown that it reduces the chemical reaction that sends pain messages to and from the brain.

Plantain
Not to be confused with the banana-esque tropical fruit of the same name, this plantain dates back to the 12th century as a poultice for everything from insect bites to wounds and burns. The plant has numerous antimicrobial properties that can help heal the skin and sooth burns and bites. The seeds are also used as the fiber source in laxatives.

Parsley
Dating back to 1629 when it was recommended and prepared for the Queen of England, parsley root has been used for health of the urinary tract. This benefit can be accredited to its ability to increase urine output. For the best result, drink tea made with parsley three times a day, or eat parsley leaves regularly for long term benefits. The chlorophyll in parsley also makes it a good breath freshener.

Watermelon
The high liquid content of watermelon, along with the natural sugars and fiber, make it the perfect snack. However, it’s much more than just a snack. Tomatoes are highly touted for their high content of the immune strengthening antioxidant lycopene. The fact is that watermelon actually contains more lycopene (40% actually) than tomatoes. If you bring one home, keep it out even once it’s cut instead of refrigerating it. This may sound strange, but you get the most benefit this way. Room temperature watermelon can continue producing antioxidants for up to two weeks.

Onions
Primarily used for seasoning, onions are high in vitamin C, fiber, folate, and vitamin B-6. They also contain large amounts of quercetin, which can help relieve allergies and has also been known to have anti-cancer effects. Studies have shown that people who eat the most onions can reduce their risk for oral cancer by 84%, colon cancer by 56%, breast cancer by 25% and prostate cancer by 71%. Red onions have the most quercetin, but pink shallots have a wider mix of antioxidants.

Lettuce
Looking at the light green color of most lettuce would generally lead one to believe that it doesn’t have the nutrients of other vegetables, but this is not the case. Iceberg lettuce contains lutein and zeaxanthin, which are carotenoids that reduce the risk of cataracts and age related macular degeneration. Add a salad at the beginning of a meal to get some of these benefits, and you’ll also likely eat fewer overall calories due to feeling more full and satisfied.