Published 1:30 p.m. UTC Jun 14, 2018
We’ve been hearing about the benefits of a Mediterranean diet for years, and now authors of a major study long cited for suggesting its heart-healthy benefits said the research was flawed.
The original study, published in 2013 in the New England Journal of Medicine suggested a Mediterranean diet can decrease risk of heart attacks and strokes. Authors said in a letter published Wednesday there were “irregularities in the randomization procedures” and they’ve revised the report.
The error was spotted earlier by John Carlisle of Torbay Hospital in England, who featured the study on a 2017 list of medical reports with questionable data.
The problem is that some of the 7,447 participants in the original study, funded by the Spanish government, hadn’t been assigned randomly to follow the Mediterranean diet, including olive oil or nuts, or a low-fat one referenced in the paper, lead author Miguel Ángel Martínez-González told NPR. In some cases, all family members were assigned the same diet, which does not constitute a random sample size. In one case, an entire village participated in the same diet, The New York Times reports.
While Martínez-González stressed this flaw only affected a small part of the trial (about 10 percent of participants), the revised study softened its language about how the diet might prevent cardiovascular disease, NPR notes.
The conclusions remain the same: A Mediterranean diet can decrease risk of heart attacks and strokes by about 30 percent among those who are at high risk of developing cardiovascular disease, the Times reports.
The Mediterranean diet is mainly comprised of plant-based foods, such as fruits and vegetables, whole grains and nuts. People who follow this diet rarely eat red meat and instead opt for fish and poultry. Butter is often replaced with olive oil.
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