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Medicine Science

The Most Important Study of the Mediterranean Diet Has Been Retracted (qz.com) 115

Zorro shares a report from Quartz: In 2013, the New England Journal of Medicine published a landmark study that found that people put on a Mediterranean diet had a 30% lower chance of heart attack, stroke, or death from cardiovascular disease than people on a low-fat diet. It received massive media and public attention when released, and since has been cited by 3,268 other scientific papers. The study had tremendous impact on the field of nutrition and health science. Yesterday (June 13), however, the journal retracted the study -- providing a new reason for skepticism about how effective the now-popular Mediterranean diet really is.

The reasons for the withdrawal are complicated, having to do with the methodology of the study. As Alison McCook of the Retraction Watch blog writes for NPR, this retraction is the result of the work of John Carlisle, a British anesthesiologist and self-taught statistician. Carlisle has spent recent years analyzing over 5,000 published randomized controlled trials (the gold standard of medical science research) to see how likely they were to have actually been properly randomized. In 2017, he reported his results: at least 2% of the studies were problematic. One was the 2013 NEJM article on the Mediterranean diet.

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The Most Important Study of the Mediterranean Diet Has Been Retracted

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  • by Anonymous Coward

    Eat what you want in moderation. Just live your life and try to be happy.

    • by corezz ( 1603659 )
      That does seem to be the pattern.
    • Re: (Score:3, Interesting)

      Comment removed based on user account deletion
      • by ClickOnThis ( 137803 ) on Friday June 15, 2018 @09:40PM (#56792916) Journal

        We humans aren't much different, with the exception of it taking a munch longer timeline.

        I saw what you did there,

      • by blindseer ( 891256 ) <blindseer@noSPAm.earthlink.net> on Friday June 15, 2018 @11:12PM (#56793148)

        There are many animals in this world in that if you give them an unlimited supply of food, they will keep on eating until they die; often in very short order.

        I grew up on a dairy farm and I'd see this happen. I personally didn't see a cow eat itself to death but I have seen cows eat until they got sick and had heard stories of people having to dispose of cows that had eaten until they died. This seems to only be true of corn feed though, a cow will know enough to stop eating grass/alfalfa/haylage eventually. I do remember a calf that didn't know enough to not eat the straw. That calf got bloated and sick constantly until it learned that straw is not good food.

      • There are many animals in this world in that if you give them an unlimited supply of food, they will keep on eating until they die; often in very short order. We humans aren't much different,

        Especially American humans.

    • by Anonymous Coward

      Thanks for the worthless advice. Eat some cyanide in moderation while I follow the traditional Okinawan way of eating.

    • The diet industry doesn’t want that.
      We have been conditioned to believe in a noble life style of self sacrifice. So if we are not meeting culture definition of beauty then we tie it with health issues. We shame ourselves and others for not trying hard enough.

      The concept of proper diets are easy. East foods with nutrients your body needs and calories in should equal calories out (to maintain weight)
      However the problem is bodies handle nutrients and calories differently. That salad and vegan diet may

    • (Eat what you want in moderation. Just live your life and try to be happy) == 42
  • Realized the sources to the diet were few and not 100% credible, ignored it, grabbed the recipes that sounded tasty, and continued living my life.

    / still fat
    // I'm a good cook, I eat a lot
    /// See also: Dom Delouise
    • by jrumney ( 197329 ) on Friday June 15, 2018 @09:49PM (#56792940)
      It has always been my firm belief that the key to a successful Mediterranean diet is consuming copious quantities of wine. Everything else becomes irrelevant once you've mastered that part of it.
    • MSM at its finest (Score:4, Informative)

      by Okian Warrior ( 537106 ) on Friday June 15, 2018 @10:26PM (#56793014) Homepage Journal

      First, some background:

      Statistical methods are based on what are known as "stable distributions". A stable distribution is one where a subset of examples, selected randomly, will have the same characteristics as the full set. Normally this refers to a bell curve, so if you have a bell curve population and you select a sample at random, then the sample mean will tend towards the population mean and the sample width will tend towards the population width.

      It is this characteristic that lets us extend measurements of characteristics from a subset to the characteristics of the whole population.

      (There are a couple of other distributions that are stable [wikipedia.org], but they are fairly rare in the real world. IIRC, Nile river flooding follows a Levy distribution [wikipedia.org], and was the first instance of a stable distribution that wasn't a bell curve.)

      This only works if the subset selection is random. If the selection isn't random, then the results can be skewed towards randomness (you won't see an effect that's there, the most likely outcome) or phantom effects that aren't really there.

      That is the defect in the Mediterranean diet study, that the participants were not placed on one diet (or the other) at random. In particular, husband and wife participants were both placed on the same diet, and in one case an entire town of participants were placed on the same diet.

      Of note: When the flawed placements are deleted from the data, the Mediterranean diet still stands and there is still a clear effect [npr.org] indicated by the data.

      "This affected only a small part of the trial," says Martínez González. When the researchers reanalyzed the data excluding the nonrandomized people, the results were the same, he adds.

      So the conclusions of the study are still strong: the diet correlates well and strongly with reduced heart attacks.

      Out of an abundance of caution and professional ethics, the study was adjusted with softer language in the conclusions.

      And yet, our noble MSM is reporting only that the study was retracted, comparing it to 50-ish other studies that were similarly flawed.

      With predictable results, such as the post this is in reply to.

      (Exercise for the reader: Is the MSM doing more harm than good here, or is it the other way around? Many, many other articles report the news with an opinion, such as "Trump meets with Kim, but it won't result in anything useful". Why couldn't NPR have a similar headline for *this* article, such as "Diet study retracted, despite being accurate"?)

      • Your point is a good one. I was excited to see that the New York Times had "That Huge Mediterranean Diet Study Was Flawed. But Was It Wrong?" as the title. Still clickbait-y, but it was nice to see that they suggested that there was more to the story and a point to reading beyond the headline.
      • But in another sense, the paper was entirely wrong: the Mediterranean diet does not cause better health outcomes.

        I haven’t read the second link, so I’d be happy to be proven wrong, but I seriously doubt the investigation found that the paper instead proves the null hypothesis. It’s extremely annoying that even purported “science” writers can’t be precise with language.

        Prediction: This article will be quoted, without a direct link to the original paper or investogation, asserting that “The Mediterranean diet [b]does not[/b] cause better health outcomes,” instead of

      • by jon3k ( 691256 )

        "Trump meets with Kim, but it won't result in anything useful"

        Not only did NPR not run this headline, I can't find any other "MSM" that did. Do you have a source?

        Also, is Fox News MSM?

      • Re:MSM at its finest (Score:5, Informative)

        by pots ( 5047349 ) on Saturday June 16, 2018 @06:32AM (#56794092)

        And yet, our noble MSM is reporting only that the study was retracted, comparing it to 50-ish other studies that were similarly flawed.

        Did you read the links? The NPR link says basically what you're saying here: the diet still has good evidence behind it, but they softened the language in the conclusion as a result of this. The Quartz article is more one-sided, but... are you really calling Quartz "MSM"?

        Let's see... Here's [nytimes.com] the New York Times coverage. I'll quote:

        That Huge Mediterranean Diet Study Was Flawed. But Was It Wrong?
        A highly publicized trial in Spain found that the Mediterranean diet protects against heart disease. Now the original work has been retracted and re-analyzed, with the same result.

        The next link from my search is USA Today [usatoday.com], I'll quote:

        He stressed this flaw only affected a small part of the trial (about 10 percent of participants) and that 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.

        So the answer to your exercise appears to be: Yes, the MSM are responsible journalists and the random news blog is not.

        • by cfrito ( 1265798 )
          Yes, if one reads the original New England Journal of Medicine story, the re-analysis confirmed the original conclusions. It's amazing that they found any differences since the the original study was conducted in Spain and the control group was all Spaniards -- who eat what? -- typically, a Mediterranean diet. The other two groups were 1.) Mediterranean diet plus extra virgin olive oil; 2.) Mediterranean diet plus mixed nuts. Both the latter groups had improved results in terms of the proportion myocardi
      • Your final point about the importance of random sampling is a good one, but on the way I'm afraid there are a number of misconceptions about how and why statistics works:

        Statistical methods are based on what are known as "stable distributions".

        No, statistical methods are based on whatever probability distribution is appropriate - they are not limited to stable distributions

        A stable distribution is one where a subset of examples, selected randomly, will have the same characteristics as the full set.

        Not quite: a stable distribution is one where the *sum* of a sample of independent random variables has the same distribution.

        so if you have a bell curve population and you select a sample at random, then the sample mean will tend towards the population mean and the sample width will tend towards the population width.

        The sample mean will always approach the population mean (in the limit of large samp

  • Sleeper (Score:5, Funny)

    by msauve ( 701917 ) on Friday June 15, 2018 @09:08PM (#56792842)

    Dr. Melik: Yes, this morning for breakfast. He requested something called wheat germ, organic honey and tiger's milk.
    Dr. Agon: [ laughs ] Oh, yes. Those were the charmed substances...That some years ago were felt to contain life-preserving properties.
    Dr. Melik: You mean there was no deep fat? No steak or cream pies? Or hot fudge?
    Dr. Agon: Those were thought to be unhealthy, precisely the opposite of what we now know to be true.

  • In other news, eating the SAD* has been repeatedly shown to produce obesity, heart disease, diabetes, halitosis, and Trump politicians. So there.

    -

    * - Standard American Diet.

    • Re: (Score:2, Troll)

      by ScentCone ( 795499 )
      Like Rosie O'Donnell, Michael Moore?

      Regardless, most Democrats think they're overweight because of genetics, while Republicans tend to think it's because of personal behavior. Gee, what a surprise.

      http://blogs.lse.ac.uk/usappbl... [lse.ac.uk]
      • Regardless, most Democrats think they're overweight because of genetics, while Republicans tend to think it's because of personal behavior. Gee, what a surprise.

        I must be a moderate because I think personal behavior is genetic.

  • Nothingburger (Score:4, Informative)

    by Jodka ( 520060 ) on Friday June 15, 2018 @09:55PM (#56792954)

    The summary is misleading because it omits mention that the randomization errors were inconsequential. The study conclusion remains the same when the improperly randomized subjects are excluded.

    from the linked article:

    It turns out approximately 14 percent of the more than 7,400 study participants hadn't been assigned randomly to either the Mediterranean diet or a low-fat one. When couples joined the study together, both had been picked to follow the same diet. At one of the 11 participating study sites, the lead investigator had assigned the same diet to an entire village and didn't tell the rest of the investigators.

    "This affected only a small part of the trial," says Martínez González. When the researchers reanalyzed the data excluding the nonrandomized people, the results were the same, he adds.

    • The randomization errors were not inconsequential. The results were the same, but the statistical certainty is now weaker. The reduction in sample size due to non-randomized samples results in a weakening of the statistical confidence interval of the findings. On top of that, they are now no longer able to eliminate (to the same degree of statistical certainty) other factors than diet as potential causes for the health improvements they found.

      Basically, it turned the study's conclusion from "we're sur
  • The Mediterranean Doesn't Exist! "The Most Important Study of the Mediterranean Has Been Retracted" -- News at 11.

    And in other news, eggs are bad for you. Oh, I've just been given a note. Eggs are now good for you. Oh, another note. Make that bad. What? Now they're good again? Are we all eating the same eggs here? What do you MEAN they're bad again? I can't even finish a sentence without you ... and now they're good. Are you looking at a stoplight or something? And now a message BAD AGAIN from
    • The eggs thing have scientifically just been first bad and then not bad, what the media then shouts about the matter is a completely different matter. The reason why it was first seen as bad was that scientists could see that high cholesterol in your blood is bad for your health and that egg contained large amounts of cholesterol, later after more studies the scientists found out that digested cholesterol does not increase your cholesterol blood levels and thus eggs are no longer bad (for that particular re
  • In other news, eggs are once again poison, red wine is still good, but chocolate is bad, going into it's 11th year keto is still a dangerous fad, 5 few types of fats and 3 new types of cholesterol were discovered, and each of them is worse than the last.

    Stay tuned for our follow up broadcast at 11, where up to 3 of those dietary facts will be reversed.

  • This is how science is supposed to work...and why religion doesn't.

  • Ob (Score:2, Funny)

    by Hognoxious ( 631665 )

    Well wop can you say? There's hardly a dagoes by without some study saying something's bad for you. I take a small spic of comfort from the fact that if you average the studies out they come down to variation plus moderation.

  • Comment removed based on user account deletion
  • People like this are the super-heroes of science, doing tons of work to find the bad science and weed it out.

Beware of all enterprises that require new clothes, and not rather a new wearer of clothes. -- Henry David Thoreau

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