
Raw data from a 40-year-old study raises new questions about fats (2017) - emmelaich
https://www.scientificamerican.com/article/records-found-in-dusty-basement-undermine-decades-of-dietary-advice/
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howlin
Note that this is mostly about saturated fat sources versus polyunsaturated
fats. These polyunsaturated fats were all high in omega 6, which is widely
regarded as less heart healthy than omega 3 oils or monounsaturated fats such
as olive oil, avocado oil, or high oleic sunflower oil. Equivocating the
results here as plant fats versus animal fats misses most of the nuance.

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zamfi
In a sense, though, I think this is exactly the point of the article: when
this study was run, we didn't know about omega-N fatty acid profiles of fats.
So things that seemed "obvious" didn't pan out in RCTs like this one.

Today, most of the RCTs about things like omega-3 fatty acids show no effect.
Why?

My guess at the root cause is a bit of scientific reductionism mixed with
overgeneralization. Omega-3 fatty acids are a great example, and often it
looks like this:

1\. Shockingly healthy population X has a diet rich in foods A, B, and C. What
do A, B, and C have in common? Perhaps it's some micronutrient in abundance
(like omega-3 in high-fat fish-eating cultures). Logically, the cause might be
that micronutrient!

2\. Early observational studies that happen to pass publication thresholds
show promising connections. People who eat salmon -- high in Omega-3 -- are
healthier! They have lower triglycerides, or cholesterol, or whatever.

3\. RCTs show no positive effect from supplementing omega-3 fatty acids.

What happens between 2 and 3? Observational studies can't really isolate the
effect of a single micronutrient, because there are a ton of interactions
happening. Probably one of those other interactions is also necessary, but we
don't know what it is -- much like how "plant fats" vs "animal fats" misses a
ton of nuance.

I'm not really sure what we can do about this, though, except stop getting
excited in phase 2?

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jfnixon
Supplementing is not the same as avoiding. As you say, the interactions are
complex. Maybe it isn't that supplements of omega3 are beneficial, since
omega3 and omega6 compete, but avoiding omega6 while having sufficient omega3
gives the benefit. Any RCT support the negative properties of omega6?

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hirundo
See the recent "FAT: A Documentary" (Amazon Prime has it) or the book "The Big
Fat Surprise" by Nina Teicholz for many more details. I found these
entertaining and compelling.

> The Frantz children always felt fortunate that their father brought his work
> home, his beliefs about the dangers of saturated fat shaping what the family
> ate. “Other kids would have ice cream; we had ice milk,” recalled Ivan
> Frantz. Bob said they were “reared on margarine,” foreswearing butter’s
> saturated fat.

I think this is key. This debate isn't about corporate shills, but honest
disagreement between sincere, hard working scientists. It shows how hard
nutrition science in particular can be.

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AtlasBarfed
So the population was mental hospitals and nursing homes?

They certainly isolated away exercise as a variable.

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AstralStorm
Likely cause is the good old bias against publishing null or negative results.

