SnakeOil? Scientific evidence for health supplements

A generative data-visualisation of all the scientific evidence for popular health supplements by David McCandless and Andy Perkins.

I’m a bit of a health nut. Keeping fit. Streamlining my diet. I plan to live to the age of 150 in fact. But I get frustrated by constant, conflicting reports and studies about health supplements.

Is Vitamin C worth taking or not? Does Echinacea kill colds? Am I missing out not drinking litres of Goji juice, wheatgrass extract and flaxseed oil every day?

In an effort to give myself a quick reference guide, I dove into the scientific evidence and created a visualization for my book. And then worked with the awesome Andy Perkins on a further interactive, generative “living image”.

Play with interactive version | See the still image

This visualisation generates itself from this Google Doc. So when new research comes out, we can quickly update the data and regenerate the image. (How cool is that??) Hopefully then this should be a useful web resources for years to come.

About the image

This image is a “balloon race”. The higher a bubble, the greater the evidence for its effectiveness. But the supplements are only effective for the conditions listed inside the bubble.

You might also see multiple bubbles for certain supps. These is because some supps affect a range of conditions, but the evidence quality varies from condition to condition. For example, there’s strong evidence that Green Tea is good for cholesterol levels. But evidence for its anti-cancer effects is conflicting. In these cases, we give a supp another bubble.

The evidence

We only considered large, human, randomized placebo-controlled trials in our data scrape – wherever possible. No animal trials. No cell studies. Many of the health claims made by the $23 billion supplements industry are based on non-human trials. We wanted to cut through that.

This piece was doggedly researched by myself, and researchers Pearl Doughty-White and Alexia Wdowski. We looked at the abstracts of over 1500 studies on PubMed (run by US National Library Of Medicine) and (which hosts meta-studies of scientific research). It took us several months to seek out the evidence – or lack of.

You can see our key results in this spreadsheet. (It’s the same spreadsheet that generates the interactive image).

Generation Game

This is our first interactive piece here on Information Is Beautiful. We’ll be doing more generative pieces over the next few months so stay tuned!


UPDATE 1: 6th Mar 2010 – We’ve updated the spreadsheet (changes in bold) and the viz after great feedback and new evidence and corrections from our amazing visitors. Thank you all so much.

Quick summary: We’ve added CoQ10, cocoa, capsaicin, L-Lysine and hyaluronic acid to the chart. And adjusted entries for Magnesium, Tumeric and Omega 3 (part of a massive downgrade of Omega 3 in fact). Read the change-log for full details

UPDATE 1: 10th Mar 2010 – Omega 3 has been downgraded in almost every category. See the spreadsheet (changes in bold) for more details.

See the visualisation | Check out the spreadsheet

Feed Us Back

As ever, we welcome your thoughts, crits, comments, corrections, compliments, tweaks, new evidence, missing supps, and general feedback. Thank you!