Corrections to the New Review Paper on Dietary Fat and Cardiovascular Risk

The meta-analysis by Chowdhury et al. raised quite a furor from certain segments of researchers and the popular media.  I find this reaction interesting.  I usually write about obesity, which is a topic of great interest to people, but my post about the review paper received more than twice my usual traffic.  People whose findings or opinions are questioned by the paper are aggressively denouncing it in the media, even calling for retraction (1).  This resembles what happens every time a high-profile review paper is published that doesn't support the conventional stance on fatty acids and health (e.g., Siri-Tarino et al. [2], which despite much gnashing of teeth is still standing*).  I'm not sure why this issue in particular arouses such excitement, but I find it amusing and disturbing at the same time.  This kind of reaction would be totally out of place in most other fields of science, where aggressive public media outbursts by researchers are usually frowned upon.

As it turns out, the critics have a point this time.  Significant errors were uncovered in the original version of the meta-analysis, which have been corrected in the current version (3).  These include the following two errors, one of which alters the conclusion somewhat:
  • The outcome of one observational study on omega-3 fatty acids was reported as slightly negative, when it was actually strongly positive.  This changes the conclusion of the meta-analysis, making it somewhat more favorable to omega-3 consumption for cardiovascular protection.
  • The authors left out two studies on omega-6 fatty acids.  These didn't change the overall conclusions on omega-6.

Read more »