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Medicine Science

What Can We Learn From The Retraction of the Mediterranean Diet Study? (vox.com) 114

Posted by EditorDavid from the overrating-olive-oil dept.
Remember that landmark 2013 study that found that people on a Mediterranean diet had a 30% lower chance of heart attack, stroke, or death from cardiovascular disease than people on low-fat diets? An anonymous reader quotes Vox: Last June, the prestigious New England Journal of Medicine pulled the original paper from the record, issuing a rare retraction. It also republished a new version [of the PREDIMED study] based on a reanalysis of the data that accounted for the missteps... But after spending several days talking with some of the brightest minds in nutrition research and epidemiology, I now feel the PREDIMED retraction is actually cause for hope -- maybe even a new beginning for the field.

Yes, studies with big flaws pass peer review and make it into high-impact journals, but the record can eventually be corrected because of skeptical researchers questioning things. It's science working as it should, and the PREDIMED takedown is a wonderful example of that. This process should bring us a step closer to what really matters: informing people who want to know how to eat for a healthy life.
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What Can We Learn From The Retraction of the Mediterranean Diet Study? More

What Can We Learn From The Retraction of the Mediterranean Diet Study?

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  • What we should learn is not to trust studies. (Score:5, Insightful)

    by hey! ( 33014 ) on Saturday February 16, 2019 @04:12PM (#58132112) Homepage Journal

    You should go on systemic reviews published in high impact factor journals.

    The reason is that the world is complex. When you look at it, even if your technique is flawless (which it won't be), you will find contradictory evidence. If you look back at landmark studies that have stood the test of time, you will just about always find procedural or analytical flaws that invalidate their conclusions. Note very carefully here: an invalid conclusion is not the same as an *untrue* one.

    The moment of scientific discovery has immense romantic appeal, but it's only the start of a long process in which that discovery is repeatedly knocked down and then propped back up again. What a systemic review paper does is go back over the *entire* chain of contradictory findings and sum up the state of the evidence.

    • The driving force in science today is grant funding, which is itself driven by citations. For example, the NIH measures "research productivity" primarily with # of citations/dollar spent. In nanotechnology, my field, we have also measured research effectiveness by number of citations. This is not some idle interest, but leads to how research funding is distributed by scientific field. This results in a negative financial incentive for in-field scientists to disagree, and positive financial incentive to show

    • Re: (Score:2)

      by tsa ( 15680 )

      Every good scientist knows that.

    • You should go on systemic reviews published in high impact factor journals.

      Systemic reviews aren't great, either. If it's a topic you care about, you should read the study yourself and evaluate it. Reproduce it if it's important enough, but with a knowledge of statistics you should be able to filter out most of the problematic ones.

      • Re: (Score:2)

        by hey! ( 33014 )

        Systemic reviews are the best way for layman to evaluate evidence. If you *do* choose the read *a* study, you need to real *a lot* of studies that cite it before you put any credence in it.

        • I don't even think you are right. Systemic reviews tend to be written by the same crappy scientists who wrote the original crappy studies. In my experience they are poorly written as often as not. Ultimately if you don't understand statistics and can't calculate the margin of error on a study, then you are hosed and there is nothing you can do.

          • Re: (Score:2)

            by hey! ( 33014 )

            YMMV of course, which is why I suggested restricting your search to leading journals that are difficult to get published in. But looking at an *individual* study is useless, unless you are committed to looking at a large number of of other papers that cite that study. Most researchers get a lot of things wrong on the first go, even the good ones.

            • I don't think it's that bad. Most papers follow a format kind of like this:

              1) Assuming X (which relies on other studies)
              2) We tested Y
              3) And conclude Z

              Usually the parts you are interested in are Y and Z. So the first thing to look for is the methodology. Is it an experiment you could reproduce and get the exact same results (assuming you had funding, of course)? In other words, did they describe it in enough detail to be reproducible?

              The next thing to look for is error bars. Have the calculated the

              • Re: (Score:2)

                by hey! ( 33014 )

                I don't necessarily disagree, but I would like to respond to this:

                If you get past those things, there's a good chance the study would be able to be reproduced if someone tried.

                This is true, but it does *not* necessarily mean that other equally valid but contrary studies could take place. The more complex a system you are talking about, the more apparently contrasting evidence is bound to be found. This is particularly true in fields like nutrition, where the funding available is low relative to the complexity of the problem being studied. It's like trying to paint a 360 degree panorama that you're studying throu

                • This is particularly true in fields like nutrition, where the funding available is low relative to the complexity of the problem being studied.

                  Most studies in the field of nutrition fall into the "inconclusive" category.

                  The more complex a system you are talking about, the more apparently contrasting evidence is bound to be found.

                  Now you're talking about this kind of thing [vox-cdn.com]. Fortunately, if someone does yet another study to determine whether coffee causes cancer, they summarize previous research briefly, in order to explain why their study is special.

                  A lot of times the problem is the media misrepresenting a study in order to be sensationalistic, and if you read the actual paper instead of the reports, it's more tame and accurate. (and sometimes scientists

  • How about (Score:1)

    by Anonymous Coward

    Any/all of Ancel Keys politically motivated bullshit studies? Let's retract his work and refigure our policy priorities in line with real science. Oh wait, can't do that and admit that 40+ years of food policy was wrong...

  • The Imaginary Mediterranean Diet ... (Score:5, Interesting)

    by kbahey ( 102895 ) on Saturday February 16, 2019 @04:25PM (#58132166) Homepage

    One thing that irks me, is that the Mediterranean Diet claims that it is based on what people of that area eat.

    Well, I am from the Mediterranean (Alexandria, Egypt), and I have to tell you that this diet is not based on reality. If anything, it is highly selective.

    Yes, olive oil, nuts, pulses and fruit are part of the diet. But there is also all sorts of chicken, duck, doves, beef, lamb, and fish, mostly cooked in clarified butter (almost the same as the ghee of India).

    If you look at Italy, Greece, Turkey, Southern France, and Spain, their cuisine has those claimed magical components, but also plenty of animal products (lamb, beef, pork, goat, rabbit, duck) and animal fat (lard, sheep fat).

    And you find the same magical ingredients in countries far away from the Mediterranean, such as Iran, Afghanistan, Turkmenistan, ...etc. Lots of nuts, raisins, lentils, beans, and fruit.

    So, this Mediterranean diet is imaginary at best, regardless of whether it works or not.

  • I don't even pay attention anymore. Just use common sense and you'll be farther ahead than you would be chasing whatever the current recommendations are.

    • Just use common sense

      wtf is common sense?

      • When it comes to diet, common sense is to eat as wide a variety of foods as possible, in reasonable quantities.

        People lack common sense because they think the quantities of food that get served to them are OK to eat all in 1 go - they're not. Your meals should not be 1000 calories unless you're bodybuilding. Every time I go out to eat, even just fast food, I usually have a third of it left over to save for later in the day.

        Oh, metabolizing what you eat helps as well. That doesn't mean join a gym, it mean

        • Good advice IMO.

          There's a lot that remains unknown and/or disputed, but there seems to be a growing consensus regarding the following, including both alternative and mainstream schools of nutritional medicine:

          * Aim for more nutrients (vitamins/minerals) and less calories, especially empty ones.

          * Avoid sugars and high-glycemic carbs (white, refined starches). At most they should be consumed as rare treats, not part of one's regular, daily diet.

          * Eat healthier thi

  • mostly cereals & vegetables with just a little bit of meat, and not raw vegetables because they can be hard to digest, i like them gently sauteed, i dont stick with any particular diet and just pay attention to my insides and what makes me comfortable and happy when it comes to foods, i stick with fresh fruit & veggies, sometimes frozen, but almost never veggies in a tin can

  • Diets have improved out of sight since my grandparents were young. Science can and does get things hilariously wrong, but on average, the correct ideas outlast the incorrect ones, if only on account of them being stronger memes. Scientific method should be seen as an accelerator for natural selection of beneficial memes; we're still nowehere clever enough to do this stuff without 95% of it being empirical study / trial and error.

  • Nothing we did not already know... (Score:3)

    by godrik ( 1287354 ) on Saturday February 16, 2019 @04:56PM (#58132254)

    We should replicate studies and confirm analysis independently before we get too excited about any results. It is hard to run this kind of studies, there are lots of variable to consider, lots of potential misreported event. We need to be careful. I don't mean that the authors are always lying on purpose, but they could have missed something important, they could have made an error. Peer review does not quite catch these things.

    Any kind of study should be taken with a grain of salt until it is replicated in multiple place.

    And I say that as a computer scientist. There are things that appear to make a lot of sense when you describe them. It does not always mean they will work. And sometimes it works in one paper, and not in other ones. Machines are never quite the same, the instances could have slightly different characteristics. Lots of things can happen. We need to be careful.

    Of course, the media just loves a good headline. So they'll print pretty much anything to sale some papers.

    • We should replicate studies and confirm analysis independently before we get too excited about any results..

      That's true, but the hitch is there will be financial interests working and braying about whatever study gives them better profit opportunities.

      Not to mention the special interest groups like vegans.

      Or what I consider the ultimate insanity of the food puritans. Healthy sugar!

      And we don't hear much about Nitrates in veggies, but Got damn! Cured meats are shit!. Holy Botulism Batman!

      Remember when cooking in Aluminum utensils was going to give us Alzheimers?

      Eggs

      All you have to do is look at who loses,

      • We should replicate studies and confirm analysis independently before we get too excited about any results..

        That's true, but the hitch is there will be financial interests working and braying about whatever study gives them better profit opportunities.

        That doesn't stop the individual from looking at Cochran reviews [cochrane.org] and so forth to get a more balanced picture and making up their own minds. I do this whenever the media bring up a new study making some claim or other.

        • That doesn't stop the individual from looking at Cochran reviews [cochrane.org] and so forth to get a more balanced picture and making up their own minds. I do this whenever the media bring up a new study making some claim or other.

          But it won't cause them to look either. A lot of people want to hear that sucrose is healthier than High fructose corn sugar, and that diet drinks cause heart attacks. Now they slurp their Healthy sugar Big Gulps with a clear conscience.

          Peeps is peeps, and for some reason they want to think that if they only eat this, or avoid that, they will live forever - at least in their minds.

          Moderation has always and remains the best advice. They won't take that advice either.

          • Sucrose, HFCS, and most artificial sweeteners are ALL unhealthy. You want to avoid all of them insofar as possible. Stevia may (or may not) be an exception. The jury is still out. It increases insulin resistance according to a few studies, and decreases it according to many others. I suspect there are mechanisms by which it does both, and that the very fact of its sweetness may be part of the mechanism behind the former. I'd prefer it over the others, but the best thing is to try to phase out sweet dr

  • I ate pretty good in my younger days when we still had the 4 food groups: Carry-out, Frozen, Pizza, and Ramen. I also had generous servings of Malt, Barley, Hops, and Yeast!

  • "I refuse to spend my life worrying about what I eat. There is no pleasure worth forgoing just for an extra three years in the geriatric ward."

    • "I refuse to spend my life worrying about what I eat. There is no pleasure worth forgoing just for an extra three years in the geriatric ward."

      That of course the question. While people mostly assume that all the dietary restrictions they put on themselves will somehow make them live foreveer, the shivering truth is even if these restrictions keep you from keeling over from say a heart attack, any reduction on one cause of death, can only increase the likelihood of dying from something else.

  • This is far too regular occurrence and it looks like ar too large a percentage of scientific studies are flawed and many are so badly flawed that their conclusions are completely wrong and sometimes the complete opposite conclusion is true.

    So why aren't universities teaching people how to do science properly and why are scientific papers constantly missing all of the bad papers they are supposed to be reviewing?

    The system looks very broken to me and I do not agree with " It's science working as it should,"

    • So why do scientists keep screwing up science?

      becaue science, it turns out, is hard.

      This is far too regular occurrence and it looks like ar too large a percentage of scientific studies are flawed and many are so badly flawed that their conclusions are completely wrong and sometimes the complete opposite conclusion is true.

      90% of everything is crap and science has never been any exception. The thing about science that works is that it isn't ultimately about the individual results, but about the corrective

      • Re: (Score:2)

        by MrL0G1C ( 867445 )

        I think the thing you're missing is there are correct methods and those methods aren't always being followed.

        • Re: (Score:2)

          by tomhath ( 637240 )
          What you're missing is that humans aren't perfect. Compare our health and lifestyle today to what people had no more that 100 years ago (e.g. the 1918 Flu pandemic that killed millions of people). You can't expect every study to be done perfectly, there are reviews and occasionally retractions. But overall the progress has been tremendous.

      • Re: (Score:2)

        by MrL0G1C ( 867445 )

        Or to put it another way, it seems that the same mistakes happen over and over and over again. What's stopping universities from determining what the top ten most common mistakes made are and tackling those through their education?

        Normally we call people who make the same mistakes repeatedly idiots.

        • [replying to both messages at once]

          I think the thing you're missing is there are correct methods and those methods aren't always being followed.

          Yep that's certainly true.

          Or to put it another way, it seems that the same mistakes happen over and over and over again.

          Also true. Though I'd like to emphasise that science keeps marching forward despite that. The same mistakes are repeated over and over again. You can pick any decade and find it, but the corrective process works, which is why we do make forward pro

        • In my mind, that's the key: universities don't teach how to do research.

          Universities teach how to use a number of tools found in research through coursework at both the graduate and undergraduate level. But that's very different than teaching how to do research. Even working on a semester-long or year-long research project as an undergraduate is very different than what an independent researcher will see. More importantly, how you approach the problem is very different as well.

          Research is writing grant p

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