Spreading Misinformation

Are Seed Oilz Bad For Humans?

Dec 01, 2023

So u/mesayousa, a fellow devotee of Scott Alexander and thus greatly to be respected in my eyes

https://www.reddit.com/r/slatestarcodex/comments/186vbqo/are_seed_oilz_bad_for_mice/kbbf7dg/

accuses me of spreading misinformation, and tells me that we should not care about whether seed oils are bad for mice, because they aren't bad for humans, and speaks to us about the harm that can come from not eating seed oils:

These are the papers that he cites in evidence:

https://pubmed.ncbi.nlm.nih.gov/15774905

Flow-mediated dilatation is impaired by a high-saturated fat diet but not by a high-carbohydrate diet

https://pubmed.ncbi.nlm.nih.gov/28526025

The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials

https://pubmed.ncbi.nlm.nih.gov/20351774

Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials

https://pubmed.ncbi.nlm.nih.gov/27434027

Effects of Saturated Fat, Polyunsaturated Fat, Monounsaturated Fat, and Carbohydrate on Glucose-Insulin Homeostasis: A Systematic Review and Meta-analysis of Randomised Controlled Feeding Trials

https://pubmed.ncbi.nlm.nih.gov/26615402

A high-fat, high-saturated fat diet decreases insulin sensitivity without changing intra-abdominal fat in weight-stable overweight and obese adults

https://pubmed.ncbi.nlm.nih.gov/24550191

Overfeeding polyunsaturated and saturated fat causes distinct effects on liver and visceral fat accumulation in humans

https://pubmed.ncbi.nlm.nih.gov/27434027

Effects of Saturated Fat, Polyunsaturated Fat, Monounsaturated Fat, and Carbohydrate on Glucose-Insulin Homeostasis: A Systematic Review and Meta-analysis of Randomised Controlled Feeding Trials

https://pubmed.ncbi.nlm.nih.gov/32114592

Omega-3, omega-6 and total dietary polyunsaturated fat on cancer incidence: systematic review and meta-analysis of randomised trials

https://pubmed.ncbi.nlm.nih.gov/32723506

Association between dietary fat intake and mortality from all-causes, cardiovascular disease, and cancer: A systematic review and meta-analysis of prospective cohort studies

https://pubmed.ncbi.nlm.nih.gov/9665108

Linoleic acid intake and cancer risk: a review and meta-analysis

I am most grateful for this attempt to correct some of my many misconceptions.

It seems to me that there is a good deal of evidence in there about whether or not seed oils cause cardiovascular disease and cancer. I have not read very much of it, but I am happy to bring it to your attention.

I am also happy to accept that the current medical consensus, arrived at in good faith, is that polyunsaturated fats are better for us than saturated fats, and that that consensus is based of a very great deal of evidence.

I personally do not trust that consensus as far as I can throw it, for all sorts of reasons that are beyond the scope of this poor blog about an old man trying to lose weight and fix his hysterical/psychosomatic/psycho-bio-social/neurasthenic/hypochondriac/somatoform/neurotic/malingering/neurasthenic illnesses.

But that is only my opinion, and I am an idiot who knows nothing, and furthermore a known sufferer of Chronic Fatigue Syndrome, which all the world knows is a made-up disease which silly old women claim to have as an excuse for bothering doctors, and you should not trust me.

Almost certainly the correct epistemological move for anyone reading this blog is to trust the vast consensus of experts over the rantings of an untrained neophyte with no relevant qualifications.

That is the official position of this blog, which is after all called the "Heart Attack Diet". Because if you try these things at home, they will probably cause you to have a heart attack, according to those who should know about these things.

I am simply quibbling, as beginners often do, and attempting faithfully and honestly to record my personal thoughts and experiences as I try to come to terms with this vast accumulation of knowledge.

Everything on this blog could obviously be interpreted as medical advice. You should not take it, because there is no good reason to believe it, and it will probably hurt you if you do. It is only for looking at, and I hope only to provide some amusement for those who, like me, find cranky contrarianism intriguing for its own sake.

With that said, one of these papers does seem to bear quite directly on the question of whether polyunsaturated fats cause obesity and/or metabolic disorders, which is the question that I am interested in here, so I decided to give it a 'close reading', as our friends in English Literature call it.

I feel that Medical “Science”, considered as an academic discipline, is to be accorded the same sort of respect as English Literature, considered as an academic discipline.

If not more! English Literature has never saved my life as far as I know, whereas medicine has saved it once to my knowledge, and doubtless several times when I didn't even notice.

This is the paper in question:

https://pubmed.ncbi.nlm.nih.gov/24550191 Overfeeding polyunsaturated and saturated fat causes distinct effects on liver and visceral fat accumulation in humans

Abstract:

Excess ectopic fat storage is linked to type 2 diabetes. The importance of dietary fat composition for ectopic fat storage in humans is unknown. We investigated liver fat accumulation and body composition during overfeeding saturated fatty acids (SFAs) or polyunsaturated fatty acids (PUFAs). LIPOGAIN was a double-blind, parallel-group, randomized trial. Thirty-nine young and normal-weight individuals were overfed muffins high in SFAs (palm oil) or n-6 PUFAs (sunflower oil) for 7 weeks. Liver fat, visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (SAT), total adipose tissue, pancreatic fat, and lean tissue were assessed by magnetic resonance imaging. Transcriptomics were performed in SAT. Both groups gained similar weight. SFAs, however, markedly increased liver fat compared with PUFAs and caused a twofold larger increase in VAT than PUFAs. Conversely, PUFAs caused a nearly threefold larger increase in lean tissue than SFAs. Increase in liver fat directly correlated with changes in plasma SFAs and inversely with PUFAs. Genes involved in regulating energy dissipation, insulin resistance, body composition, and fat-cell differentiation in SAT were differentially regulated between diets, and associated with increased PUFAs in SAT. In conclusion, overeating SFAs promotes hepatic and visceral fat storage, whereas excess energy from PUFAs may instead promote lean tissue in healthy humans.

As far as I can tell it's a great study. But what would I know?

I certainly couldn't ask for a better design, and I would hope that it will be successfully replicated by various different groups of people, at which point I think it should go straight into the bank of known truths that we can just rely on without worrying too much.

It directly compares palm oil to sunflower oil, and to my eyes it shows beyond reasonable doubt that if you deliberately overfeed healthy young people on fatty muffins for a few weeks in such a way that they gain weight then:

They gain weight.

As far as how much people eat goes, the effects are the same. You need the same number of extra muffins to cause people to gain the same amount of weight.

But if you overeat SFAs (palm oil), the extra energy gets stored as about half fat, half 'lean tissue'.

And if you overeat PUFAs (sunflower oil), then it gets stored as some fat, but mostly 'lean tissue'.

And also the authors say that they see the same effects in similar animal studies (they mention rats and mice, but I think they're mainly talking about rats?).

I hope that that is a fair summary, but of course you should read it for yourself, because I do not have the skills necessary to read studies.

I had hoped that u/mesayousa might comment on my summary, but he appears to be busy elsewhere at this time.

I don't know what it means for the causes of obesity.

But it does seem to show that PUFAs and SFAs behave really differently as food sources. They're not just interchangeable.

And it hints that whatever's going on might work the same in rodents as in humans.

And there also seems to be something a bit funny going on. The extra energy in the SFAs got stored as fat. Where did the extra energy in the PUFAs go?

What do you think?