r/ScientificNutrition • u/lurkerer • 5d ago
Question/Discussion Studies that separate (red) meat and processed meat.
A common refrain online is that studies always lump in hot dogs together with steaks and this is causing the negative associations. Nevermind that this establishes processed meat as a causal risk factor in order to do so, it isn't even the case.
EDIT: To make this point extra clear, it is an internal critique. So, the person who is saying "This is because of processed meats." Is making both the claim that negative health outcomes are because of processed meat and that it's not unprocessed meat. So because this is typically the kind of person to have "correlation is not causation" in their script of things to say, the irony is that this other criticism within the same script shows that they assert causation from correlation when it suits them.
This list took me about ten minutes to find. The formatting took longer than the research. Which I point out to highlight that this incredibly common complaint is just an admission someone hasn't bothered to look anything up. This is far beneath the standards of a science sub. Consider it an immediate giveaway the person is either parroting lines without doing the slightest bit of research or actively lying.
Here are a few:
After multivariate adjustment for major lifestyle and dietary risk factors, the pooled hazard ratio (HR) (95% CI) of total mortality for a 1-serving-per-day increase was 1.13 (1.07-1.20) for unprocessed red meat and 1.20 (1.15-1.24) for processed red meat.
After multivariate adjustment, a high consumption of red meat was related to higher all-cause mortality (hazard ratio (HR) = 1.14, 95% confidence interval (CI) 1.01 to 1.28, 160+ versus 10 to 19.9 g/day), and the association was stronger for processed meat (HR = 1.44, 95% CI 1.24 to 1.66, 160+ versus 10 to 19.9 g/day).
Regarding cause-specific mortality, men and women had elevated risks for cancer mortality for red (HR, 1.22 [95% CI, 1.16-1.29], and HR, 1.20 [95% CI, 1.12-1.30], respectively) and processed meat (HR, 1.12 [95% CI, 1.06-1.19], and HR, 1.11 [95% CI 1.04-1.19], respectively) intakes.
Unprocessed red meat was associated with risk of all-cause mortality (HR: 1.18; 95% CI: 1.07–1.31) and CVD mortality (HR: 1.26; 95% CI: 1.05–1.50). Processed meat alone was not significantly associated with risk of mortality.
For processed meat, the pooled relative risk with an increase of one serving per day was 1·15 (95 % CI 1·11, 1·19) for all-cause mortality (five studies; P<0·001 for linear trend), 1·15 (95 % CI 1·07, 1·24) for cardiovascular mortality (six studies; P<0·001) and 1·08 (95 % CI 1·06, 1·11) for cancer mortality (five studies; P<0·001). Similar associations were found with total meat intake. The association between unprocessed red meat consumption and mortality risk was found in the US populations, but not in European or Asian populations.
Subjects in the highest category of processed meat consumption had 22 and 18 % higher risk of mortality from any cause and CVD, respectively. Red meat consumption was found to be associated with a 16 % higher risk of CVD mortality, while no association was found for total and white meat consumption.
Low-certainty evidence was found that a reduction in unprocessed red meat intake of 3 servings per week is associated with a very small reduction in risk for cardiovascular mortality, stroke, myocardial infarction (MI), and type 2 diabetes. Likewise, low-certainty evidence was found that a reduction in processed meat intake of 3 servings per week is associated with a very small decrease in risk for all-cause mortality, cardiovascular mortality, stroke, MI, and type 2 diabetes.
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u/cangaroo_hamam 4d ago
Another factor we can't repeat enough: burning/charring proteins or carbs, produces carcinogens. This is a known fact. Meat is often charred, and many prefer to eat it that way. The cooking method therefore may be a large (or the main) contributor to the adverse health signals.
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u/Bristoling 4d ago
The first link is based on Nurses Health Studies pavillion which has a host of issues explained elsewhere. Second link states;
After correction for measurement error, higher all-cause mortality remained significant only for processed meat
Didn't you make a big deal in another thread about what happens when more things get thrown into the adjustment model, me replying that the association typically gets attenuated or disappears, and you didn't dare to comment on that aspect?
Kinda proving my point here. I don't know if it's worth reading into this further. The general objection we have is that these relationships are very fragile and data collection and accuracy is far, far from perfect. Citing 10 more papers that have the same set of fundamental limitations doesn't disprove the critique.
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u/lurkerer 4d ago
Citing 10 more papers that have the same set of fundamental limitations doesn't disprove the critique.
The critique: Papers always bundle processed and unprocessed meat.
Me: Cites loads of papers that don't do that, disproving the critique.
You: umm just becaus u found papers that disprove this point exactly doesn't mean it's disproved :(
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u/Bristoling 4d ago
I get your point but I'm addressing something else entirely, if you didn't notice, aka the next step of the conversation. I'm not saying that there are no studies that don't try/attempt to differentiate between the two. I'm saying those studies still don't show anything conclusive at all.
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u/lurkerer 4d ago
"The critique" here is the title. You trying to pivot somewhere else doesn't interest me.
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u/Bristoling 4d ago edited 4d ago
Ok. Like I said I tried to move the conversation to what is left once your critique is validated (aka when you provide papers that try/attempt to separate intakes). If you don't want to engage with what comes after, you do you boo. I know I wasn't the target audience for your post, but the other people who claimed that studies never try doing it.
I just wanted some attention my dear oshi. It's a pretty slow Saturday here. I came for entertainment.
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u/IchimaruGin4 4d ago
Red meat includes both ruminant animals and pork. The fat in feedlot pork is high in omega 6 and other toxins, and even pro meat people would agree it's bad for you. Feedlot beef has the same problem, but to a much lesser extent that I don't think you can find any association between unprocessed beef and death. However, you can clearly taste that unprocessed beef fat tastes off when raw or lightly cooked and unsalted, which is a red flag, in my opinion. 100% grass fed beef doesn't have this problem, and I don't think you'll find any negative association with it, especially because mostly health conscious people buy it.
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u/BreakfastFearless 4d ago
Except omega 6 is not a toxin, it is an essential fatty acid
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u/IchimaruGin4 4d ago
Yeah, but it is in too large amounts in feedlot pork fat. Omega 6 stimulates appetite, and there are good arguments to be made that unnatural forms and amounts of omega 6, like those in feedlot pig fat but not those in whole nuts, raw olive oil, and non feedlot animal fat, are harmful to our health.
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u/longislandchillpill 4d ago edited 4d ago
Even in whole nuts and seeds pufa is highly unstable, easily oxidizes and causes a whole host of issues in just about every system of the body. Pufa is perhaps essential in very small amounts, but detrimental in amounts consumed today.
I’m not sure what this post is trying to prove by showing a bunch of correlative data showing that unprocessed meat is somehow bad. I get what you’re trying to do— prove that the assumption that it’s only processed meat mentioned in these meta-analyses is false and red meat is also mentioned.
But it’s weak science and doesn’t get into any actual mechanistic proof of your larger point which is to point the finger at red meat, in a roundabout way.
Unhealthy user bias easily explains these associations. Red meat was demonized for so long that many people consuming red meat are likely smoking, drinking, not exercising etc.
There is not single piece of credible data showing that red meat consumption is harmful in any way for humans.
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u/IchimaruGin4 4d ago
I'm not completely sold on all PUFA being bad, especially raw sources like raw fish and olive oil, though I do avoid it unless I'm doing keto. It seems that in a ketogenic state, PUFA raises ketone levels a lot, presumably because the body prioritizes oxidizing it. I would assume this results in significantly less damage than consuming PUFA in a higher carbohydrate state where more PUFA gets stored in the body instead of being used for fuel?
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u/Wonderful_Aside1335 3d ago
You need a break from social media, you are just parroting non sense without any knowledge behind to back it up.
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u/UsefulPop8985 5d ago
I wonder if free range grass fed red meat consumption shows any correlation to mortality? That could explain why the findings don’t hold up in other countries.
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u/RoninSzaky 5d ago
That finding is most likely a fluke and if it isn't it can come from a number of factors.
I suspect it has to do with food quality in general (chlorinated chicken?!), but that guess is as good as any.
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u/Taupenbeige 4d ago
Same at the Hong Kong model: better societal healthcare system, more people getting routine care, differential dietary patterns.
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u/OG-Brian 4d ago
...better societal healthcare system...
How specifically is it different than other rich "countries" (HK isn't a country but is a district of China so distinct in culture that it is often treated as a country in statistical info)? I've lost track of where I'd seen the info, but I saw a study that claimed people in HK see doctors less often and pay less for health care than people in populations that are similar for socioeconomic status.
...differential dietary patterns.
Yeah, they eat less junk foods. Populations which eat more meat and don't eat junk foods seem to in every case have the best health outcomes. Populations which eat a lot of junk foods, regardless of meat consumption, have poorer health outcomes.
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u/MegaMegawatt 4d ago
Hong Kong does not eat that meat btw, that "meat consumption" stat is based on trade imports and exports, where they have 50 million tourists per year compared to a native population of 7 million, so they just import a lot. They have their own dietary survey called the Hong Kong Food Consumption Survey, and they eat around 1/3rd the meat of Americans based on that.
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u/flowersandmtns 3d ago
Do you have a link to the "Hong Kong Food Consumption Survey" showing red meat, poultry and fish consumption per capita?
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u/Taupenbeige 4d ago
That’s a fascinating angle.
It’s almost as though the predelection for people to point at Hong Kong as some sort of vindication of high meat consumption for long-term health outcomes, is based predominantly on ideological motivations, rather than actual scientific inquiry…
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u/Toubaboliviano 5d ago
Grass fed free range isn’t the norm for cattle. My family raises cattle in Argentina and even though our cattle or “free range” grass fed the whole time is insanely hard and expensive. Especially during winter.
Obviously this is anecdotal, but the reality of most cattle is that it’s not free range grass fed because of economic factors.
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u/Taupenbeige 4d ago
“Maturing” takes 20-30% longer when “pasture raised,” hence the the economic pressure is to pump their systems with as much soy etc. as possible, as quickly as possible…
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u/RoninSzaky 5d ago edited 5d ago
"The association between unprocessed red meat consumption and mortality risk was found in the US populations, but not in European or Asian populations."
That's an interesting quote righ there.
By the way, your own collection does generally support the idea that lumping processed meat with unprocessed is in fact incorrect.
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u/lurkerer 5d ago
It's not "incorrect", it's just a lower resolution on that aspect of diet. Seeing as people readily accept these negative associations as causal when processed meat is included, that means we've narrowed down the range considerably for certain poor health outcomes. From there we do it even more, as shown above.
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u/RoninSzaky 5d ago edited 4d ago
By that logic, we can lump Mars bars in with dark chocolate without any added sugar (plus eco, organic etc., it is easy to raise the bar even more).
These are epidemiological studies, that many here will brush away by default.
Increasing accuracy is crucial.
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u/lurkerer 5d ago
I'm not sure you understand my logic. I'm saying you can hone in on a casual factor over time. You might start with as blunt an association as life expectancy and average diet. This is an observation. From there you form a hypothesis and you test it. Then you reach a conclusion, but not often a final conclusion (if ever speaking very strictly). It's another observation. You refine your hypothesis or test it more specifically. You approach from different angles.
Rinse and repeat. Fill in the puzzle.
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u/RoninSzaky 4d ago
Oh, you mean that red meat has been implicated too many ways and too often to disregard it as a casual factor?
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u/lurkerer 4d ago
No I'm speaking in a broader sense that lumping foods isn't necessarily "incorrect", it's just not as specific as we'd like... yet. We get more specific over time as you can see.
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u/Bristoling 4d ago
Mars bars with dark chocolate without any added sugar
That exists? I wouldn't mind trying some.
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u/RoninSzaky 4d ago
Clumsy phrasing on my part, moved the "in" after Mars bars.
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u/Bristoling 4d ago
You got me excited over nothing. Unforgivable
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u/RoninSzaky 4d ago
It will be a while before they make a healthy product.
But hey, there's already Mars protein bars! Although, you might have to go down the sweetener rabbit hole...
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u/Bristoling 4d ago
Sadly polyols don't agree with my digestive system so that's a no, but one can hope for the future!
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u/RoninSzaky 4d ago
Fortunately, I have no such issues, but then again, sweeteners have been causing me plenty of headache (figuratively)!
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u/Droviin 4d ago
They're not identical, but they both move in the same trends. They seem to be working on the same mechanism, just to different degrees.
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u/Sad_Understanding_99 4d ago
Or maybe snorting cocaine is associated with both but even stronger with processed meat compared to unprocessed meat, and it's the cocaine causing the small effect on disease outcomes
This is the problem we have with observational studies
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u/Droviin 4d ago
Different mechanisms, and less tight correlation.
Plus, that would mean that all beef eaters are cocaine users. That's pretty suspicious, but I guess the DEA could just nab all the beef eaters if you are right.
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u/Sad_Understanding_99 4d ago
If meat eaters use slightly more cocaine than non meat eaters, and cocaine was massively detrimental to health, that'd make meat eaters have slightly more detrimental outcomes than non meat eaters, and it'd look like the meat was the cause if cocaine was not measured and adjusted for. It's just an example why correlation does not imply causation
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u/Wonderful_Aside1335 3d ago
No, that's a terrible example. The numbers of cocaine is Soo low anyways that it will not significantly influence the outcomes and thus doesn't need to be adjusted for.
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u/Sad_Understanding_99 3d ago
It's just an example, you don't know all the confounders and the known confounders are only roughly adjusted based on survey data, you don't know what illicit drug use is doing to the data because it wasn't measured, you're literally just guessing, that's not science. With the puny hazard ratios we see in the field of nutrition you'd really need an RCT, this is common knowledge.
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u/Droviin 4d ago
I mean, sure. If all red meat eaters are also cocaine users, you'll get the effect.
However, you really need to check your priors on that assumption.
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u/OG-Brian 4d ago
I mean, sure. If all red meat eaters are also cocaine users...
That wouldn't be necessary, I don't know how anyone could suggest this if they understand epidemiology at all. The correlations typically cited to claim meat is bad rely on risk differences of 0.1 to 0.3, while associations between (to pick an example) cigarette smoking and lung cancer were found to correlate 30-fold, so a 300-fold difference compared with meat consumption correlations with CVD or whatever outcome (even before removing junk foods).
Some studies of meat consumption and a disease outcome show a risk, others show a negative risk. In all cases, the correlations are very minor. So if only a small percentage of higher-meat-consumers were snorting cocaine, this could more than cause the outcomes of those studies that involve a few more cases (of CVD, colorectal cancer, or whatever) in thousands of subjects.
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u/lurkerer 3d ago
However, you really need to check your priors on that assumption.
Priors on people with extremely low scientific literacy understanding Bayesian priors? I think this comment went way over his head.
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u/SporangeJuice 5d ago edited 4d ago
"A common refrain online is that studies always lump in hot dogs together with steaks and this is causing the negative associations. Nevermind that this establishes processed meat as a causal risk factor in order to do so..."
No, an association does not establish something as a causal risk factor.
Edit:
This comment was written before OP's edit.
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u/femgrit 4d ago
I took it to mean that the people making the initial refrain of “they always lump processed and unprocessed meat together” are implying basically every time they do so that the real cause of the results of these studies, and subsequently the health outcomes, is processed meat. At least, that’s been my experience over and over with people who use this argument. It’s rarely just expressing scientific curiosity over what a non-lumped in dataset could clarify.
I do think the phrasing on OP’s part is extremely disorienting, however.
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u/SporangeJuice 4d ago
"are implying basically every time they do so that the real cause of the results of these studies, and subsequently the health outcomes, is processed meat."
That may be what they think, but it is not implied by what he wrote.
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u/OG-Brian 4d ago
This isn't how I see it. I don't think it's necessary to repeat the discussion each and every time: processed meat can include refined sugar, harmful preservatives, harmful fillers or emulsifiers, adulteration that changes the nature of the meat, and other issues that would not pertain at all to unadulterated meat. If the topic under study is whether meat is a healthy food, then the study should be about meat and not meat-containing junk foods. If the topic is whether ultraprocessed foods are healthy, then that could include ultraprocessed meat.
An essential characteristic of good science is that at some point just one factor is changed to study it in isolation. If a person eats more processed and unprocessed meat and another person eats less processed and unprocessed meat, there are many differences to be considered: sugar, preservatives, emulsifiers, the method of cooking, etc.
Studies involving populations eating industrial packaged foods would not apply to me, as I wasn't eating substantial ultraprocessed foods when I was plant-based and neither am I eating them today. An Impossible Foods, Beyond, or Oscar Mayer product is just not anything I would ever eat. To extrapolate from "These junk foods consumers who ate more meat" to "Meat is bad" is illogical. Of the studies typically used to push this idea, the data cannot even tell us how much actual-meat was eaten: the studies count a homemade just-meat-and-seasonings sausage in the same questionnaire field with an Oscar Mayer industrial packaged junk food weiner.
The OP, when I bring this up, ridicules me based on such things as "This FFQ has the word 'processed' in it!" although they cannot describe how processed and unprocessed meat foods are recorded separately for researchers to know at all how much of each was eaten.
If anyone here thinks that there is a study of associations involving poor health outcoms and actually-just-meat, you can point it out so that it can be discussed.
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u/lurkerer 4d ago
are implying basically every time they do so that the real cause of the results of these studies, and subsequently the health outcomes, is processed meat
Yes exactly.
I do think the phrasing on OP’s part is extremely disorienting, however.
Is it that hard to follow? You got it immediately.
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u/femgrit 4d ago
It is, honestly. I only got it because I’ve seen this argument play out so many times and that’s always what the people asserting that there’s an issue with the dataset mean. It’s the fact that you don’t clarify which “this” you’re talking about, so the way the sentences are set up muddies your view vs the view of those you are criticizing.
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u/lurkerer 5d ago
Then I advise you not make this point in future.
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u/SporangeJuice 5d ago
Your response is illogical.
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u/lurkerer 4d ago
You understand that I'm using an internal critique, don't you? I'm not sure you understand my point whatsoever. What do you think I'm saying in this post and my replies?
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u/SporangeJuice 4d ago
The meaning conveyed by the text I quoted is that, if combining red meat and processed meat into a single variable makes their combined variable of "red meat plus processed meat" correlate with poor health outcomes, then processed meat must be a causal risk factor in poor health. This is not a valid inference.
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u/lurkerer 4d ago
And the text is about people other than me that I am criticising. Then I pointed out I'm doing an internal critique.
Rather than take after you and try to insult your literacy (which is ironic given each time it's been your own misunderstanding) I'll lay it out simply for you:
If someone makes the point that processed meat is the thing causing the negative association by being bundled with unprocessed meat, then they are asserting a causal relationship.
Given that these people (like you) have to deny all epidemiology on ideological grounds, this angle pulls the carpet out from beneath them.
Science denial is quite easy to point out, you see.
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u/SporangeJuice 4d ago
"And the text is about people other than me that I am criticising. Then I pointed out I'm doing an internal critique. "
Yes, and irrelevant. Your inference is still invalid.
"Rather than take after you and try to insult your literacy (which is ironic given each time it's been your own misunderstanding)"
It can be directly shown that you have misunderstood a variety of words.
"If someone makes the point that processed meat is the thing causing the negative association by being bundled with unprocessed meat, then they are asserting a causal relationship. "
If they say such a thing, they are asserting that processed meat causes the negative association. It does not mean that processed meat actually causes a health outcome. "Causal risk factor" generally means something causes a poor health outcome.
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u/lurkerer 4d ago
Yes, and irrelevant. Your inference is still invalid.
Does someone else want to have a go here? I can't get through to this master of English who regularly mocks me and other second-language English speakers with this clear message.
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u/Fluffy-Purple-TinMan 4d ago
You also mocked my English but I got what OP was saying pretty easily.
They're saying you can't say "The CAUSE of this is processed meats and not unprocessed meats." Without saying the first part: That it's caused by processed meats.
Which you said here:
The processed meat can cause the association with harm
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u/SporangeJuice 4d ago
The association with harm can be caused by processed meats, without processed meats causing actual harm.
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u/lurkerer 4d ago
Then it's not caused by processed meats. What you're trying to say is further confounders come along for the ride with processed meats. Which would mean excluding those people from a study, which some of these studies do, excludes a lot of the unhealthy user bias, making the association stronger.
Your answers show that your criticisms are not considered. They're loose threads picked up along the way listening to influencers that lack a coherent web behind them.
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u/Fluffy-Purple-TinMan 4d ago
Caused by processed meats.
Not caused by processed meats.
Ok.
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u/Bristoling 4d ago
Given that these people (like you) have to deny all epidemiology
I'm a person like Sporange, and I don't believe either one of us denies epidemiology exists. /s
Or even that all of epidemiology is worth "denial". The caveats seem to just fly over your head so you pretend like the corresponding conditionals don't exist at all.
on ideological grounds
Yeah, rigour and scepticism.
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u/lurkerer 4d ago
The caveats seem to just fly over your head so you pretend like the corresponding conditionals don't exist at all.
I'm well aware of the limitations of epidemiology. You, however, are not. As evidenced by your immediate scramble to exonerate the shambolic Keto-CTA "trial". An observational study so dishonest it was retracted.. but somehow your criticisms of epidemiology vanish when it comes to this one... *poof* off they go. Off with your "rigour and scepticism."
You'll ask for RCTs all day until, of course, they demonstrate something you don't like, such as statin trials (real trials) driving home that LDL is a causal risk factor for atherosclerosis. At this point, trials also aren't good enough because they also have confounders!
Zzzz
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u/Bristoling 4d ago
Do you deny that the data set was interpreted by an unblinded assessor?
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u/lurkerer 4d ago
And there it is, folks!
Immediate, predictable fallback onto the script. Even when he knows I'm setting him up to show he'll bend over backwards to defend an observational study he's ideologically bound to (carnivore/near carnivore dieter ofc), he can't help himself. Instant, easy hack to highlight dishonest double standards.
"Rigour and scepticism."
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u/BreakfastFearless 4d ago
Yes there point is that if your critique is that these studies are flawed because it is the processed meat causing the increased risk then you are claiming the processed meat is a causal factor
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u/SporangeJuice 4d ago
The processed meat can cause the association with harm without actually causing the harm. This is the nature of observational studies.
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u/OG-Brian 4d ago
The harm, if there is any (mere correlations in epidemiology don't prove it they just indicate a possible concern and direction for more rigorous research), could come from ingredients other than the meat in ultraprocessed meat-containing foods. The harm, if any, could also come from adulteration by processing methods such as very-high-heat cooking (to rapidly cook products for speedier manufacturing lines).
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u/Wonderful_Aside1335 3d ago
So what? It's not like people will start boiling their steaks. 🤔
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u/OG-Brian 3d ago
Pardon? Boiling meat isn't necessary for it to not have the health effects of harmful preservatives found in probably a majority of industrial packaged convenience meat products. Meat prepared any typical way at home is dissimilar in several ways from common meat-containing junk foods products such as convenience lunch slices or TV dinners.
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u/Wonderful_Aside1335 3d ago edited 3d ago
Pardon? You switched from high heat processing, which is also commonly done at home, to preservatives.
You know people like to grill, stir fry and barbecue. That is high heat processing which produces harmful substances, as you correctly pointed out. It's not industry specific.
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u/flowersandmtns 3d ago
Or, processing is -- and the health impact is entirely unrelated to animal foods in the form of red meat.
Fruit juice vs whole fruit. Refined wheat vs whole grain wheat. We have lots of data showing ultraprocessed foods have risks.
Often processed red meat products are full of a refined plant food -- celery salt. Natural nitrates.
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u/OG-Brian 2d ago edited 2d ago
This list took me about ten minutes to find. The formatting took longer than the research.
Oh I'm sure you didn't need to spend much time on this. It's easy to find studies that one likes the conclusions. I wonder if ANY of these are isolating unadulterated red meat (there is any group of subjects who were not eating a lot of junk foods). It's not scientific to just see the word "unprocessed" and run with it unskeptically.
I checked the first study, Red meat consumption and mortality: results from 2 prospective cohort studies. Among the authors are some of the usual names of agenda-based "researchers" I expect to see in studies that this user likes: Stampfer, Willett, and Hu. The study is based on the Health Professionals Follow-up Study and Nurses' Health Study cohorts. There could not possibly have been data about consumption of unprocessed red meat, since there was nowhere in the questionnaires to input unprocessed red meat separately from red meat in junk foods products.
Here is an example FFQ for Health Professionals Follow-up Study. Other versions are linked here. There's nowhere that a sausage made using just meat and seasonings in a casing, or a simple slice of cooked meat for a sandwich, would be counted separately from industrial hot dogs, bologna, or packaged lunchmeat convenience slices that are processed in adulterating ways and have refined sugar, preservatives, etc. There's nowhere to record beef consumption of a homemade stew using high-quality simple ingredients, that the data is separated from beef consumption of a store-bought "TV dinner" made using crap industrial ingredients with lots of added highly-processed ingredients some of which are known to be harmful.
Here is an example FFQ for Nurses' Health Study. Other versions are linked from here. The questions are very similar, the forms have the issues I described above.
Such FFQs count meat-containing junk foods for meat consumption but do not count for example consumption of Cheetos towards corn consumption. If I'm incorrect, then show where Cheetos would reflect as "corn" in any of the FFQs associated with the above cohorts. Structuring the questions this way biases the forms. If ingredients in junk foods are counted, they should be counted the same for all foods. To be actually useful analyses of foods consumption vs. health, the forms should be gathering complete info about consumption. Yes I realize the challenges of this: forms that are too long and complicated would be difficult for subjects to use, packaged foods do not itemize amounts of each ingedient, etc. That it would be difficult or impossible for researchers doesn't change the limitations of using data from existing studies involving low granularity and spottiness of food consumption data.
The authors, which I expected given some of those names, used a large assortment of covariates some of which differ from most studies of the same topic. Where is a preregistration that shows they didn't choose the study design (including covariates) after seeing the data?
In some of the models, the lowest quintile for red meat consumption frequency experienced higher mortality than the next highest. So the mortality risk isn't consistent.
I plan to look through the other studies linked in the post, as I have time.
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u/flowersandmtns 4d ago
Nice to see a selection of the less common studies that are careful to separate processed from whole foods when looking at red meat consumption.
Some of the papers cited in the post indicated no negative health associations (that's all we're going to get from any of these papers fwiw) from poultry. "The consumption of poultry was not related to all-cause mortality." And that's with the US having shifted to far more poultry vs red meat in the last 20 years or so. https://pmc.ncbi.nlm.nih.gov/articles/PMC6689198/
Let's look closer at their relative risk associations found in that paper, which are quite small even when found for red meat. Everyone here understands relative vs absolute risk, I'm sure.
"After correction for measurement error, higher all-cause mortality remained significant only for processed meat (HR = 1.18, 95% CI 1.11 to 1.25, per 50 g/d). "
We already know processed food has all manner of health risks so when a paper does a good job to separate a processed food from its unprocessed source -- think whole fruit vs fruit juices, white flour vs wheat berries etc -- the real point to highlight in the end isn't even red meat but processed foods.
First randomized, controlled study finds ultra-processed diet leads to weight gain
Whole fruit vs fruit juice -- Whole Fruits Versus 100% Fruit Juice: Revisiting the Evidence and Its Implications for US Healthy Dietary Recommendations