According to Cancer Research UK, "the term 'superfood' is really just a marketing tool, with little scientific basis to it". Although superfoods are often promoted as preventing or curing diseases, including cancer, Cancer Research UK cautioned that they "cannot substitute for a generally healthy and balanced diet". According to Catherine Collins, chief dietitian at St George's Hospital in London, the term can be harmful: "There are so many wrong ideas about superfoods that I don't know where best to begin to dismantle the whole concept."