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What Can We Learn From The Retraction of the Mediterranean Diet Study? (vox.com)
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.
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.
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.
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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.
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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.
Good lord, welcome to the middle ages.
Is it common sense that the fructose half of sucrose is metabolized in the liver by much the same pathway that processes ethanol (which if abused, in either case, contributes to fatty liver disease)?
No, it is not.
Is it common sense that the pancreas contains a melatonin receptor, so that your metabolic response to carbohydrates varies throughout the day?
Is it common sense that ulcers are mainly caused by Heliobacter pylori?
Is the effect of Toxoplasma gondii on motorcyclist and mouse behaviour common sense?
Is it common sense that fecal microbiota transplants would prove more effective in treating C. difficile than vancomycin?
Is it common sense that wholesome fresh fish potentially contains toxic levels of methyl mercury that bio-accumulate in adipose tissues?
Is it common sense that the high-productivity crops introduced during the agricultural revolution (not yet using GMO breeding techniques) remain as nutritious as the original heirloom crops?
(Besides, that was a trick question. There were three separate agricultural revolutions as human population exploded, so there are—logically—three entirely different tiers of heirloom throwbacks; the only reason this hasn't shown up at a Whole Foods near you is that Amazon's marketrons have yet to figure out how to make Silver Heirloom, Gold Heirloom, and Platinum Heirloom sound appetizing—though it does accurately reflect viable price points, given the associated yields.)
Diet is super important. We can't go around making naive assumptions. Neither can we trust failed epidemiology to untangle these incredibly complex signals. However, from the microbiome (and proteomics) much truth shall flow, even if it proves to be slow going.
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.
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 that related scientific fields are problematic (and thus less worthy of funding). In this context of correlation between funding and citations, reviews should be viewed with great skepticism.
In this case, science was advanced by introduction and acceptance of better statistical standards driven by competitive cross-disciplinary communication. (Leading to a main conclusion of TFA at Vox: the system works.)
In my experience, validation only happens when scientists from other fields are able to reproduce and expand upon your results.
Alcohol is a literal poison.
That was the reason humans started producing it. It killed all of the microbes and other parasites that they didn't understand and couldn't see and meant that you wouldn't shit your own eyeballs out from illness you could get from water due to poor sanitation. Historically beer had much lower alcohol levels for the stuff that workers were drinking out in the fields or that was being served at meals.