The latest episode of Medical Frontiers is part of a special series which looks at superfoods around the country. This time we visited Oita Prefecture, where fewer people have died from colorectal cancer over the past 10 years than anywhere else in the country. Research has found that's due to 3 foods the locals eat regularly that help maintain gut health: kabosu citrus fruit, shiitake mushrooms and onions. We'll look at the part these superfoods play in the local diet, share the latest findings on their key components and bring you some healthy, delicious recipes using them.