Here is a data visualization that compares various superfoods and nutritional supplements based on the evidence of the health benefits they deliver, as well as how popular they are with scientists and the general public.
Click the image to launch an interactive version. It lets you choose how to sort and sift; in addition, hovering over a balloon causes it to expand — and gives you more data about that item for a particular purpose.
from David McCandless.
Items that fall under the 'no' to 'slight' evidence categories are probably snake oil.