News that I do not know if and when it will arrive in Italy, which unfortunately is not the only one of its kind, and which is indeed yet another story in which a large scientific study is criticized and revised following the discovery of gross errors in the collection of data on the reference sample. This time it is the Mediterranean diet that pays the price. You know those studies from which it should be deduced that the Mediterranean diet is good for health and is linked to a reduction in the risk of cardiovascular diseases or to a reduction in the risk of other diseases? Well, a Spanish study that appeared in 2013 and lasted almost 5 years, on a sample of over seven thousand people, proved unreliable according to a group of investigators:who, after the reports of some researchers, analyzed the data in their possession and discovered that there was no possibility of identifying a causal link between the Mediterranean diet and the reduction of cardiovascular diseases by 30% in the subjects analyzed.
Put simply: the study stated that eating the Mediterranean diet reduced the risk of cardiovascular disease by 30%. But to reach this conclusion, the researchers would have had to have the sample follow the Mediterranean diet, which has not always happened .

After the review of the data, the conclusions of the study have changed: it is now read that the Mediterranean diet can reduce the risk of cardiovascular disease (it can) and not that it reduces the risk. We then moved on to talking about probabilities thanks to an adjustment.
And we are talking about a large study, which has had a huge media coverage.
But that is not an isolated case : from 2000 to 2010, 40% more scientific studies were published every year. Of the 1.4 million studies published year by year, however, 700 are withdrawn or heavily corrected years later. In most cases the studies are withdrawn because it turns out a manipulation of the data and more: those that are retracted are not all studies that have fallacies, but only those for which the scientific journal accepts a review. This is a complicated operation, because newspapers tend to decline all responsibility and thus reduce the rate of articles reviewed. And of course, in the meantime, the study may have made headlines, given that the possible revision arrives years late, as in this case. And the news that came out, all the articles on the study that we then read in the newspapers and on the web, do not contain the corrections.
What does it mean? We think about diet, nutrition, sport and all the news we read about new studies that talk about this or that.Today anyone can find studies that state everything and the opposite of everything. And very often people only read the conclusions or what is reported in the newspapers (whose editors in turn only read the final conclusions of the study): without knowing that perhaps those same studies contain problems in the analysis of the data, which perhaps they will be highlighted a few years later, as long as the newspaper that published them accepts the corrections!