red peppers

Photo: Thinkstock

4 of 7
Red Bell Pepper
This immunity-boosting superstar contains roughly 60 percent more vitamin C—which triggers the production of white blood cells that fight off germs and bacteria—than its green counterpart. It may also keep you looking young: A study in The American Journal of Clinical Nutrition found that people with diets high in vitamin C were less prone to wrinkles, possibly because the nutrient spurs the production of collagen.