Lessons from the MIND trial, by Gary Taubes (substack)

(Bob M) #1

This is “Lessons from the MIND Diet Trial” by Gary Taubes, which is on a “substack” (still not sure what this is) from Unsettled Science, mainly run by Nina Teicholz.

The “MIND” diet is some combination of Mediterranean and DASH diet, and was tested in a randomized trial to gauge effect on the brain, eg, prevent or limit Alzheimer’s as one possible benefit.

There are multiple epidemiological studies where this appeared to be true, so they decided to do an RCT.

Unfortunately, it failed.

As always, Gary Taubes is very perceptive and persuasive.

In my mind, he makes this point, which I think is really what is happening with the vast majority of (if not all) epidemiological studies:

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These epidemiological studies seem to gauge what is happening to a select group of people, those people who are wealthier and try to eat “healthier” and probably exercise more, smoke less, drink less, have better healthcare, etc. They just happen to eat more vegetables or olive oil, or whatever researchers are looking for, but that does not mean those foods provided whatever benefit the researchers think they provided. Causation is unlikely or at least not proven.

(KM) #2

In what way did the RCT fail? Did it fail to show the results they were looking for, or did the trial itself not finish?

(Bob M) #3

The results were “bad”, meaning negative.

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(KM) #4

Thank you. As I’ve chosen not to mindfully dash anywhere, I’d hardly think of it as a failure. :wink:

(Bob M) #5

No problem.

Just to be clear, what has been happening, and I’m sure will continue to happen, is that researchers will look at people who have submitted indication of what they ate. (Typically – or perhaps only – through food frequency questionnaires, FFQs, which ask you how many times you eat something, and the amount.) They then go through this material and “score” it to see how well it matches with whatever diet they think is good. Then, they’ll declare a benefit for Diet X over a normal diet.

Take this study, for instance. They used the DASH diet criteria and scored people’s diets based on that. The people who scored higher in the DASH diet were supposedly less depressed than those who ate a “normal” diet (with lower DASH scores):

One problem, as Gary Taubes points out, is that these types of studies often compare people and not diets. Those people who are richer, take better care of themselves, drink less, smoke less, eat “healthily”, etc., are compared against people who aren’t.

Then, when you run an actual RCT, you find out there’s no difference, because you’re no longer comparing people, but instead comparing diets.

NOTE: you still could be comparing people, in the sense that some people are “adherers”, meaning they exactly follow what you want them to do, and others aren’t. But if the trial is random, hopefully each group has the same amount of those people.

(KM) #6

There’s also the touchy confirmation bias. “I invested a lot in this, therefore it was a good idea because I invested in it . If there’s a problem, I don’t feel any need to highlight it, in fact I did not notice.”. We’re all human, but it’s a shame so many people don’t excuse themselves just because their position is subjective.

(Bob M) #7

That’s definitely true. That’s what I think keeps The Harvard School of Epidemiology in business. :grinning:

(Alec) #8

It didn’t. It was a spectacular rip-roaring success. It showed how good a Mediterranean diet is for mental health compared to the other diet it was compared to (I think it was simply encouraging “healthy eating”). The result was clear: there was no difference, therefore the Mediterranean diet does not confer any special mental benefits.

That, to me, is an unqualified success. But let’s be serious, in science, which is what these chaps were supposed to be doing, then success or failure are totally subjective terms, what science is about is the result, not the judgment around whether the result was good or bad or right or wrong… the result was the result. End of.

(Edith) #9

Which is the big problem. The whole idea of experimentation is to test whether or not your hypothesis is correct. If your hypothesis is incorrect, that still means the experiment was a success: you still learned something. Well, that’s how it’s supposed to be. These days, if your hypothesis is proven to be incorrect, that is considered a failure.

(Bob M) #10

This is one of the points Taubes was trying to make: This “negative” test should be reported far and wide. We know that the MIND doesn’t work, at least not over the time period given (3 years, I think). But even when reported, it’s characterized in what might have gone wrong instead of “It doesn’t work”.

Negative results are as important as are positive results.

It’s like the massive WHI Dietary Modification Trial (DM):

https://sp.whi.org/about/SitePages/Dietary%20Trial.aspx

This doesn’t show the results, but they were negative. No benefit from lower fat, lower saturated fat, more fruits and vegetables. But you never hear about it.

(Jack Bennett) #11

The problem seems to be that the scientists (and journalists) aren’t willing to report the results honestly.

Since “everybody knows” that:

  • Hearthealthywholegrains are really good for you
  • Arterycloggingsaturatedfat is really bad for you
  • The MIND diet is the best possible diet because it increases hearthealthywholegrains and reduces arterycloggingsaturatedfat among other good things (yay vegetables and olive oil, boo meat!). Also, US News keeps ranking it among the top 3 diets! That’s meaningful, right?

It’s the rhetorical fallacy of begging the question: assuming the hypothesis is already proved, and using that proof to … prove the hypothesis.

“Well, since we already know that this is the best diet, this massive, expensive trial has to have had some flaws because if had been a perfect trial, it would have agreed with us that this is the best diet.”

(BuckRimfire) #12

Thank Chaos, someone who knows what “begging the question” means!!! A nice rhetorical device ruined by the subliterates who also brought you “gift” as a transient verb and the nonsense phrase “hone in” in recent years.

Unfortunately, this class of subliterates seems to be reaching saturation in the media and podcasting world…

(Bacon is a many-splendoured thing) #13

We need to home in on them and hone their literary skills.

P.S.–You forgot to mention using “reference” as a verb. I hate it when people verb nouns and noun verbs, lol!

(KM) #14

And when did ‘fraught’ become an adjective?

(Doug) #15

About a hundred years ago, i.e. used without an object.

(BuckRimfire) #16

Uh oh, you might have me there. “Cite” is a lovely word and “refer to” has a certain Old World charm, but using “reference” as a verb doesn’t have the same nails-on-a-chalkboard feel to me as my previously-mentioned…

(KM) #17

Really? I had never heard fraught used that way til maybe 15 years ago. I remember the first time I heard “it was very fraught”. I believe fraught is an archaic version of “freighted”. As in, “laden with”, or “burdened with”. So, laden with what? With fraughtness? :laughing:

While I’m on a curmudgeonly rant, myriad. Synonymous with much, or many, not “a lot”. “We had a myriad of problems, our journey was fraught” might sound fancy, but it translates to, “We had a much of problems, our journey was filled with”.

(KM) #18

Well said.

(Doug) #19

Yeah - “fraught with peril,” etc. That’s the way I think of it - “laden with” is the perfect way to portray it. But, the word is listed as an adjective, and I’ve read things where the subject is understood, and then they or it were “fraught” or “full-fraught.” Usually there is the sense of being distressed; negative connotations and whatnot.

‘Myriad’ - this one is about the same for me, either way. ‘A myriad of solutions,’ or ‘myriad solutions’…

I think it’s what one is used to. :slightly_smiling_face: I grew up hearing the past form of “plead” as “pled,” as with “he pled guilty.” 20 or 30 years ago on American TV it was morphing into “pleaded,” - and I know that also is correct (I’ve looked it up many times), and (insultingly) ‘pleaded’ is listed first, arrggghh.

(Bacon is a many-splendoured thing) #20

From www.etymonline.com:

fraught (adj.)

late 14c., “freighted, laden, loaded, stored with supplies” (of vessels); figurative use from early 15c.; past-participle adjective from obsolete verb fraught “to load (a ship) with cargo,” Middle English fraughten (c. 1400), which always was rarer than the past participle, from noun fraught “a load, cargo, lading of a ship” (early 13c.), which is the older form of freight (n.).