I found a fascinating website today called “Information is Beautiful“, in particular I was interested in the post “SnakeOil? Scientific Evidence for Health Food Supplements“. This post is based on HUGE amounts of data and is a lot to take in at first glance, it certainly doesn’t look like a conventional graph.
So what’s it all about?
The chart shows whether there is good, conflicting or poor evidence for taking a specific food supplement. The size of the circle shows how popular a supplement is (based on Google hits). The height of the circle shows whether the evidence for taking it is good, conflicting or poor (the higher the circle the better the evidence). If you click on the diagram and then move your mouse over to the right hand side of the screen you can select the medical condition you are interested in. I chose cancer, so what does it show?
If you look at supplements and cancer there is strong evidence that beta-glucan and selenium are helpful (they are near the top) however, selenium is much more popular than beta-glucan as it has a much larger circle. You might be wondering why selenium also appears lower down the table, I need to investigate the studies in more detail to find out why. The circle at the top relates to “chemotherapy” and the one lower down to “cancer”, I’m not sure if they mean chemoprevention rather than chemotherapy?
Why do I like this chart?
It is based on a huge amount of data, over 1,500 abstracts, just to create one graph! It uses high quality studies found in pubmed and Cochrane (see my earlier post on “Where do scientists look for information on the web“). It only looks at studies in humans (not cells in a dish in the lab) and these studies need to be large, placebo controlled, this means the data is as reliable as it can be. Furthermore the information that the chart is based on is freely available, online, so you can follow it up yourself.
The author also has a book out so if you want to see a whole range of data presented this way have a look.
As an aside, I first saw data displayed in this “moving circles” format in a TED talk by Hans Rosling called “Hans Rosling shows the best stats you’ve ever seen“, this talk is about how people perceive the developed/developing world and how if you actually look at the data this world view is far too simplistic. This talk is well worth watching, it was recorded in 2006 and has been updated several times (the updates are good too). The talk discusses health in the broadest sense and argues strongly that data should be made publically available. Please watch it.