Linoleic acid–good or bad for the brain? (2020) | Hacker News Reader

Linoleic acid–good or bad for the brain? (2020)

nature.com

46 pointswhalesalad77 comments

From the conclusion: "In conclusion, this review presents evidence that excess LA in the food supply might adversely affect the brain. The potential benefit of LA lowering merits detailed evaluation in well-designed and adequately-powered clinical studies, to test whether this translates into tangible reductions in the risk of neurodegenerative disorders and neurodevelopmental abnormalities at a population level."

So eat more Omega 3 and not too much Soy Bean Oil... maybe. I do wonder about diet just being another thing for people to argue about on the Internet, we know so little about the interplay between gut microbiome, food, genetics and health and doing proper clinical trials (in humans) to have some certainty is nearly impossible.

I'm pretty sure there is no way to thread the needle. The center cannot hold. Nothing in excess is the best I can come up with for longer-lasting health.

“Eat food. Not too much. Mostly plants.”

(https://www.nytimes.com/2007/01/28/magazine/28nutritionism.t...)

Here is something from Dr. M. Greger. He typically has good research to back his articles:

https://nutritionfacts.org/question/what-would-you-suggest-a...

broken link... I think you meant: https://nutritionfacts.org/questions/what-would-you-suggest-...

Thanks.

Greger is a vegan fundamentalist who ignores any evidence to the contrary of his chosen vegan lifestyle. That’s not science. At all.

I believe this is an exaggeration. I have no horse in this race, but perhaps you are judging the person’s work based on his vegan advocacy rather than on the merit of the research that he identifies.

Any food that is disproportionately represented in our post hunter-gatherer diet, especially processed food, must have an element of "bad for you" in it.

Eat whole foods and maintain a level of exercise and don't sweat the small stuff.

Any medicine that is disproportionately represented in our post hunter-gatherer treatment plans, especially synthesized chemicals, must have an element of "bad for you" in it.

Drink clean water and boil willow bark and don't sweat the small stuff.

Well, yeah. There's a reason these drugs all have side effects, and that the first principle of medicine is, Do No Harm.

We have a long history of interventions leading to worse outcomes. It's just sometimes those bad outcomes are worth it by evading worse outcomes.

Why should the general population increase their intact of salicin via Willow Bark?

What kind of advice is that?

I think he's satirizing the parent poster, by copying his logic and saying that we should eat willow bark rather than taking aspirin pills.

That doesn't make sense since we ate anything we could find and evolution only selected for procreation, not for long term health. The very things we ate for most of our history could very well be bad for us long term, like increase our cardiovascular disease risk.

I don't see why I would accept appeals to nature in favor of the balance of our best evidence.

Not if you consider parents tend to care for their descendants -> healthier parents long-term will have more successful descendants, probabilistically speaking.

ex: unfit parents won't be doing a great job of keeping their children and/or grandchildren out of the mouths of hyenas.

Note we're talking evolutionary time scales here, this is hunter-gatherers in loin cloths on the savanna territory.

Get kids and die, perfect way to procreate.

>Eat whole foods

Vegetable oil/soybean oil/canola oil/other refined oils is not a whole food.

Unrefined olive oil, butter/ghee, lard etc is.

ghee is refined butter and you could argue butter is refined cream. Those definitions are all fuzzy and context-dependant.

“Refined oil” has a specific documented definition, and to be clear I’m talking about chemical refinement. See here: https://youtu.be/Cfk2IXlZdbI

The distinction you are making is irrelevant and trollsome

> “Refined oil” has a specific documented definition

Care to link it?

> and to be clear I’m talking about chemical refinement. See here: https://youtu.be/Cfk2IXlZdbI

What makes it "chemical"? Does the refinement process chemically alter the molecular structure of the lipid molecules?

>Care to link it?

Edible oil refining is a set of processes or treatments necessary to turn vegetable raw oil into edible oil. https://en.wikipedia.org/wiki/Edible_oil_refining

>What makes it "chemical"? Does the refinement process chemically alter the molecular structure of the lipid molecules?

The process uses chemicals as opposed to physical interventions, which is why it is called chemical refinement. Chemicals used in this process can include: phosphoric, citric, sulfuric or hydrochloric acids, EDTA, bleaching earth/bentonite, phospholipase enzymes, caustic soda and silica, plus high temperatures up to 240C.

Did you watch the video? Chemical refining is the traditional method used since ancient times. It can be used for all fats and oils. Each step of the refining process has specific functions for removing some undesirable compounds. Chemical refining follows the six-step process outlined at the link (degumming, neutralization, washing and drying, bleaching, dewaxing, and deodorizing).

The process also removes the important bioactive molecules in oil such as tocopherols and polyphenols (which can act as antioxidants), squalene and sterols.

>>What makes it "chemical"? Does the refinement process chemically alter the molecular structure of the lipid molecules?

>Did you watch the video?

So your definition of "chemical" hinges on what happens in a youtube video? I doubt that's the case. What specific steps makes it "chemical"? Am I correct in assuming your criteria is "involves steps that uses scary sounding chemicals"?

Olive oil isn’t a whole food. Neither is butter, ghee, nor lard.

If you extract and concentrate some fraction of a food and eat it disproportionately to what is present in the whole product, you are by definition consuming a not-whole thing.

You can cold press canola oil. It's one of the best oils to consume rivaling olive oil.

Though this is a good example of why the heuristic is nonsense. When we replace saturated fats like your "whole foods list" with pufas like canola oil and your "refined list", we see human health outcomes improve.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4744652/

Things like this are so nit picky and nuanced it really isn’t worth caring about unless you are already doing everything else right.

People ignore low hanging fruit in their quest for health, like analyzing vegetable oils is pointless when you still eat tons of sugar, don’t sleep enough, don’t exercise, drink too much, etc.

>analyzing vegetable oils is pointless

On a personal scale perhaps. On a commercial scale though - similar to what happened to trans fats - and given how much vegetable oil is in processed food, a conclusive result could have a monumental impact on the food supply

there is low hanging fruit, sure, but a substantial amount of our food - even things that you might assume are 'healthy' - are loaded with these terrible oils. autism/adhd/neurodivergence is skyrocketing, as-are late-stage health problems like alzheimers and parkinsons. all of this is pretty well correlated with the rise of our race-to-the-bottom agricultural practices involving pesticides like glyphosate and mass cultivation of crops for seed oils.

this should not be ignored.

There have been some studies recently screening older people who grew up with more restrictive diagnostic criteria for autism that suggest that increasing rates of autism diagnosis are likely purely the result of changing diagnostic criteria and increased awareness rather than increased prevalence of austism.

polio affected 8-37 out of 100000 people between 1940 and 1950 and everyone remembers it. CDC has identird 11 communities with 1 out of 36 8 year old children have been diagnosed with autism in 2020. Estimates place roughly 1/3 of those have less than 70 IQ. So let's say 1 out of 108 children.

Sort this table by LA. Use/eat oils that have the lowest amount possible. https://en.wikipedia.org/wiki/Linoleic_acid#Dietary_sources

Coconut oil, Butter/Ghee, Olive Oil, Lard...

>Coconut oil, Butter/Ghee, Olive Oil, Lard...

The problem is that most of them (minus olive oil) are high in saturated fats, which are also bad. Out of the frying pan, into the fire.

nah, saturated fats are not bad. that is the myth big ag wants you to believe.

people will often look at old photos and wax poetic about how youthful and thin everyone was. why? they were eating saturated fats and not seed oils.

Are you confusing "fats" with "saturated fats"? Fats in general might have been vindicated, but the evidence for saturated fats being bad for you is still pretty strong[1]. Feel free to provide any sources to the contrary.

[1] https://en.wikipedia.org/wiki/Saturated_fat#Association_with...

Anything that I say will be misconstrued as conspiracy theory. Suffice to say this information is incorrect, and there is a growing snowball of evidence to suggest so. I for one do not trust the American Heart Association - they are a bunch of crooks funded by lobbyists, big agriculture and massive conglomerates. They got their start helping Proctor and Gamble market Crisco (poison in a tub) as being healthier than animal fats. In the 60s they got in bed with the tobacco industry to prove that cigarettes were not bad for you. A lot of the "studies" we have right now which paint saturated fats in a bad light are not true to the mission of science.

>Suffice to say this information is incorrect, and there is a growing snowball of evidence to suggest so.

Can you present some examples of this "growing snowball of evidence"?

>A lot of the "studies" we have right now which paint saturated fats in a bad light are not true to the mission of science.

What makes you think that? Is it just based on funding/affiliations alone? Or do you have specific methodological concerns about the studies that they use, that your studies don't have?

There is an alternative rail of nutritional science, you might call it the alt-right of nutritional science, that is taking a second look at the research (or dearth of such) that was used to develop the current mainstream canon of saturated fats bad, statins good, etc.. and presenting a competing case - and cause(s) of obesity, metabolic syndrome, high cholesterol, CV disease, etc.

If you read enough you sort of absorb it, someone else can cite some good reviews I'm sure. I will just drop a few names here if you want to investigate - Rhonda Patrick, Eric Berg, Peter Attia...

Edit: here is a published review, just the tip of the iceberg https://www.jacc.org/doi/10.1016/j.jacc.2020.05.077

Add Andrew Huberman to the list!

>Edit: here is a published review, just the tip of the iceberg https://www.jacc.org/doi/10.1016/j.jacc.2020.05.077

I skimmed the review and the conclusion seems to be "saturated fat from certain sources probably isn't bad for you"[1]. If we take that at face value, and go back to the original question of whether to replace vegetable oil with oils high in saturated fats (eg. palm oil or ghee), I think the answer is still "no". The article talks specifically talks about foods like whole fat dairy (not pure butter), unprocessed red meat (not lard) and dark chocolate (not palm oil).

[1] https://www.jacc.org/cms/asset/ee10bd12-77af-4f74-b725-7ba77...

“Just the tip of the iceberg” is the operative term there

"Tip of the iceberg" for what? That saturated fats isn't always bad for you? I think that was adequately proven in the original study. As for whether ingesting oils high in saturated fats is good for you, or whether you should be replacing your other fat consumption with them, those aren't even addressed by the study. If that's really "the tip of the iceberg", that doesn't bode well for the rest of the studies, unless for whatever reason you're withholding the strongest studies.

What kind of fats do you think your ancestors have eaten for hundreds of thousands of years?

Disclaimer: I have spent a lot of time working in ag-tech (spent many years at FarmLogs, a YC company) and I have a lot of experience in this space (industrial agriculture at massive massive scale)

Here is a nice summary post that links to a handful of studies that disprove the theory that saturated fats are bad: https://www.healthline.com/nutrition/5-studies-on-saturated-...

Here is a great video that discusses the way glyphosate is killing us: https://www.youtube.com/watch?v=Aw16LPVnNco

Here is a pretty exhaustive explanation of why the American Heart Association is full of shit: https://www.reddit.com/r/nursing/comments/rqhp7t/the_america...

Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease https://pubmed.ncbi.nlm.nih.gov/20071648/

> Conclusions: A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat.

Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis https://openheart.bmj.com/content/2/1/e000196.short?rss=1&ut...

> Conclusion: Dietary recommendations were introduced for 220 million US and 56 million UK citizens by 1983, in the absence of supporting evidence from RCTs.

Saturated fat is not the major issue https://www.bmj.com/content/347/bmj.f6340.full

A systematic review of the evidence supporting a causal link between dietary factors and coronary heart disease https://pubmed.ncbi.nlm.nih.gov/19364995/

> Insufficient evidence (< or =2 criteria) of association is present for intake of supplementary vitamin E and ascorbic acid (vitamin C); saturated and polyunsaturated fatty acids; total fat; alpha-linolenic acid; meat; eggs; and milk.

America’s most widely consumed oil causes genetic changes in the brain Soybean oil linked to metabolic and neurological changes in mice https://news.ucr.edu/articles/2020/01/17/americas-most-widel...

Soybean Oil Is More Obesogenic and Diabetogenic than Coconut Oil and Fructose in Mouse: Potential Role for the Liver https://journals.plos.org/plosone/article?id=10.1371/journal...

You like your bacon fat, we get it, you're still a quack.

https://www.zeroacre.com/blog/are-seed-oils-toxic

https://apps.who.int/iris/bitstream/handle/10665/366301/9789...

this is a meta-analysis of carefully selected studies.

What makes you think this list of studies is "carefully selected"? What makes your studies not carefully selected? In other words, if anti-saturated fat people levy the same accusation against the pro-saturated fat studies, why should I believe the pro-saturated fat side over the anti-saturated fat side?

sorry dawg at this point it is exhausting to argue with you. the facts are out there.

We don’t - pigs are fed omega 6s and their fat is unfit for humans to eat because of that. Stick to ruminant fats, preferably grass fed and grass finished.

A double blind, randomized, controlled trial showed that replacing saturated fat with seed oils high in linoleic acid significantly reduced cardiovascular disease and all cause mortality https://www.ahajournals.org/doi/10.1161/01.CIR.40.1S2.II-1

Unfortunately the full text of this study isn't on SciHub, but it's a very good study. They assigned veterans to one of two mess halls randomly, and in the experimental group they fed them food with the fat content replaced with corn oil (which is 46:1 omega 6 to 3 ratio). They also did a pre-study to make sure the fat-replaced food was palatable and hard to distinguish from unaltered food higher in saturated fat. The experimental group had significantly lower CVD outcomes and lower all cause mortality.

Don't worry about linoleic acid, it's either benign or healthy.

Like for anything else in nutrition, it is meaningless to say that linoleic acid or any specific kind of oil is healthy or unhealthy.

Only when describing the complete daily intake for some category of nutrients it is possible to say whether the quantities that are used are healthy or unhealthy.

In most human studies it is pretty much impossible to feed all the participants with exactly the same food and to vary independently various ingredients over long times in such a way as to obtain a reasonably certain conclusion.

For instance, in most days around 90% of my daily intake of fatty substances comes from a mixture of 4 oils: 50 mL of extra-virgin olive oil + 20 mL of cold-pressed sunflower oil (required to provide enough linoleic acid and enough vitamin E) + 5 mL Schizochytrium oil (provides enough DHA & EPA omega-3, can be substituted by 10 mL of fish oil, e.g. cod liver oil) + 1 drop of oil containing D3 & K2 vitamins.

According to the current knowledge, this mixture of oils is healthy.

Nevertheless, it is not possible to say that any of its components, e.g. olive oil or sunflower oil, are healthy in isolation, unless the total daily consumption and the total daily consumption of any other fatty substances are specified.

Where do you think our ancestors got their linoleic acid intake?

https://en.wikipedia.org/wiki/Naturalistic_fallacy

Where do you think our ancestors got their water? Certainly not highly purified and disinfected water straight from a water treatment plant and piped to their house. Should we go back to drinking from lakes and rivers?

>https://en.wikipedia.org/wiki/Naturalistic_fallacy

You probably meant to call my argument an appeal to nature. You seem to really know your stuff.

>Where do you think our ancestors got their water?

Lakes and rivers.

>Should we go back to drinking from lakes and rivers?

Preferably yes. I came back from a camping trip yesterday where I strictly drank from lakes and rivers, and it's very refreshing compared to city water.

I suppose this wasn't the gotcha you had planned in your head.

You drinking from a lake has nothing to do with the enormous impact of poor drinking water on the human population.

You are free to do whatever you want, but ignoring well understood issues of the world over a single personal experience is the though process of a small child.

https://www.theworldcounts.com/challenges/planet-earth/fresh...

Perhaps it's because English is not my first language, but I find it confusing to read "this is evidence that .... might ....". Isn't the purpose of evidence to prove a claim? If there is no conclusive evidence, I would expect it to be phrased along the lines of: "Preliminary evidence suggests that... might...".

The purpose of evidence is to provide support for a claim. However in colloquial speech we generally speak of someone having "evidence" of something when they have absolute proof.

100% agree.

The more specific you get about a diet, the more specific you need to get about the person eating it. So long as most dietary advice is designed and tested at population scale, it's going to be fuzzy and inconclusive.

Even the most basic advice we can give today comes with asterisks.

Nutritional studies, as stated above, always turn into people being massive certain about their positions (saturated fat vs omega 3 vs omega 6 fanboys!). I'd just assume that pretty much nothing in nutrition is proved beyond a reasonable doubt...

For what it's worth my guess is that having the wrong stomach bacteria can make all nutrition better or worse for you. And your genetics, birth mechanism, and even epigenetics all play too big a part to make blanket statements about anything. Fibre for the bugs will be the biggest thing people are missing and blunt all the supposed bad health effects of things like linoleic acid.

This seems likely a garbage-y study. It's a narrative study, not even a meta-analysis, so it's more of proposing a hypothesis rather than stating a fact. The current science shows that seed oils, and omega 6 (aka linoleic acid) fatty acids, are either benign or healthy. There was a very popular hypothesis that the omega 6 to 3 ratio was important for health, popularized in the early 2000's and getting revived now by counter-culture nonsense people, but the science has not backed that case up.

They study they link to citing neuro-development issues is https://pubmed.ncbi.nlm.nih.gov/28420388/ - which is based on a food intake survey, and it's not a controlled study, it's looking at cohorts from another study. All they checked for was linoleic acid intake, and unless you're specifically checking for food source, this usually means it comes from processed food, which is more likely the culprit than the 6 to 3 fatty acid ratio.

There is no known effect of seed oil / omega 6 intake on inflammation, which is shown in quite a few controlled studies. Seed oil intake replacing saturated fat intake has also been shown to significantly reduce CVD outcomes.

I think you should try eating three teaspoons of heart-healthy canola oil with breakfast and document the results to dunk on garbage science peddlers.

This is a very good example of the type of revival I'm talking about! There is lots of emotion in this space, which dominates the discussion over science.

Yes, exactly! Science is a fantastic way to discover truths about reality and apply them to your own life. For example, putting 15 grams of canola oil in your daily breakfast cereal.

I know you're a troll, but I'm not sure if you understand the implication of what you said. I do eat seed oils. I don't have heart disease. You can't feel arterial plaque building up, the first symptom of CVD is often a fatal event, so I'm not sure what you think I'd learn unless I did it for decades. And it wouldn't matter if I did have heart disease, n=1 is usually irrelevant in dietary hypotheses. Here's another n=1 if you think it's important: https://twitter.com/TheCarnivoreKid/status/14731222725798338...

Whoa, no need to get emotional. You're coming up with all these excuses and deflections against systematically consuming the benign and/or healthy canola oil. Why is that?

Also see: https://en.wikipedia.org/wiki/Israeli_paradox

Incidentally it seems like sunflower, safflower and soybean oils are way more common in packaged products now, higher in omega-6, presumably as a sub for palm oil. Canola has a more ideal composition among the common vegetable oils in packaged products.

One note is that most of the crops grown for seed oil are "high oleic" varieties that produce a fat makeup more similar to Canola oil than you'd previously see for those crops.

Many, but notwithstanding crops, they will be identified as such in the package ingredients. Anecdotally, I still see bog standard sunflower oil more often than the high-oleic variant.

For anyone who is confused at the significance here, I looked into the whole "Seed oils = bad" thing the other day and this claim was at the heart of it (no pun intended). Basically the idea that seed oils usually contain higher levels of linoleic acid, and butter does not, and therefore tl;dr excess butter/animal fat is not bad for you and does not cause heart disease in the way that people think it does. You can see a list of fats ranked by LA content here: https://www.news-medical.net/health/Oils-Rich-in-Linoleic-Ac...

Not saying this is correct or anything, just providing the missing context for anyone asking why Linoleic Acid is in a headline.

Thanks. There are oil/fat wars going on in research to protect billion dollar industries, so this is not surprising. A better and more helpful headline would be “whole foods are healthier than processed foods.” But everyone knows that already.

That is a good heuristic, but the hard part for people is evaluating foods at the periphery of that heuristic like chocolate and tofu and nut milk and canola oil which improve human health outcomes.

That said, and I'll quickly grant: most people in the west aren't making the mistake, say, eating too much seitan and nut milks and unsweetened 80% chocolate (all processed foods), so I won't nitpick too much.

This is a false dilemma as not all oils are high in linoleic acid or omega 6. Olive oil is the least likely to oxidize.

What quantities are we talking about? A daily serving of tofu, or ???

About two tablespoons of store-bought ranch dressing will put you at the 2% number that the article suggests as the high end of preindustrial intake.

(11g of unsaturated fat in 2 tablespoons of Hidden Valley Ranch, assume soybean oil because it's cheaper, which is ~50% LA, so about 50 calories, which is 2% of a 2500-calorie/day diet)

There is no "one quick trick" that will keep you healthy. It's a whole plethora of habits and activities that make a difference, not an individual one.

Well, yes, but that's beside the point. Processed food often contains lots of cheap seed oil which is rich in linoleic acid. People consume this stuff in vast quantities. It's worth figuring out what is or isn't poisoning people.

I've read it can leech mercury from silver fillings, resulting in brain toxicity (the "amalgalm disease" IIRC).

Is there any truth to that?

Reply on news.ycombinator.com