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Popular Mediterranean diet study under fire: Do you still have confidence in published nutrition science?
Many people expect nutrition science to help them live a healthy, long life. Despite what often seems like contradictory advice (butter or no butter?), nutrition research has consistently presented a positive picture of the Mediterranean way of eating. But even mighty Med research isn’t immune to missteps.
In June, the prestigious New England Journal of Medicine retracted the lauded 2013 study, “Primary Prevention of Cardiovascular Diseases with a Mediterranean Diet,” based on data gleaned from Spanish participants in the PREDIMED (Prevención con Dieta Mediterránea) trial. Errors uncovered in the randomization procedure of certain trial subjects showed that about 20% of study participants were not randomly assigned to a diet in the proper manner.
The Journal published a corrected version of the study in which the authors used reanalyzed data, and to the relief of olive oil lovers everywhere, results still showed that participants adhering to a Med-style diet (e.g., consuming more extra-virgin olive oil or nuts) slashed their heart disease risk over a nearly 5-year period by about 30% compared with a control group that simply received advice on how to reduce fat intake.
Some researchers believe study retractions like this are a good sign that flaws can be caught, the record corrected and science strengthened. But others who were not involved in the study aren’t sold on the republished results, going so far as to suggest that the suspect methodology may indicate serious red flags like deliberate data manipulation. And then there is the concern that dozens of other studies out there have used PREDIMED data to shape their conclusions.
In the wake of this news, do you still have confidence in nutrition science to help direct healthy eating habits? Are you concerned that this study’s shortcoming is a tipoff that many other investigations may have serious flaws that would weaken their evidence?
Do you remain convinced of the power of the traditional Mediterranean diet to promote better health? Send your responses to Sandy Todd Webster at [email protected].
Matthew Kadey, MS, RD
Matthew Kadey, MS, RD, is a James Beard Award–winning food journalist, dietitian and author of the cookbook Rocket Fuel: Power-Packed Food for Sport + Adventure (VeloPress 2016). He has written for dozens of magazines, including Runner’s World, Men’s Health, Shape, Men’s Fitness and Muscle and Fitness.
