That's interesting. The Wikipedia page for linoleic acid (https://en.m.wikipedia.org/wiki/Linoleic_acid) says this under Health Effects:
> Consumption of linoleic acid has been associated with lowering the risk of cardiovascular disease and premature death
Linking this study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7326588/
It's so hard to get any conclusive answers at all in food/health science...
Most vegetable oils, the main exceptions being olive oil and high-oleic sunflower oil (not classic sunflower oil), have a very high content of linoleic oil, so the daily intake can be obtained from less than 2 spoons of oil.
Those who use for cooking vegetable oils high in linoleic acid, or who eat mostly industrially-processed food, typically eat significantly more linoleic acid than the recommended intake.
When linoleic acid is in excess over what the body needs, it can be stored only in limited quantities in reserve fat, which must contain other fatty acids in higher proportions. Therefore the excess part of the linoleic acid, over what can be consumed or stored, must be transformed into those other fatty acids, in the liver.
This extra work for the liver is undesirable, and when the processing capability of the liver is also exceeded, then some of the fat in the body can have an abnormal composition, too high in linoleic acid.
The best is to eat mostly vegetable oils that are high in oleic acid, because those also include enough linoleic acid to cover all needs, and if they are eaten in excess, their fatty acids are just used to synthesize human reserve fat, which has a similar composition.
I find it's very hard to even identify controversies, scientific mysteries and open questions. The posture adopted tends to always give the impression of consensus and knowledge.
I was surprised to learn that myself recently.
Furthermore, coconuts are a seed, and coconut oil is often explicitly cited as an alternative to seed oils.
"Seed oil" is a reasonably proxy for the sort of high polyunsaturated oils we should probably avoid eating, but it's a heuristic for identifying products with bad lipid profiles, not a law.
Sunflower oil is mostly linoleic acid; its profile is unhealthy according to current thinking (and my shaky understanding). You’re right about olive oil, which is supposedly good for your heart.
EDIT: unless by “high-oleic sunflower oil” you’re referring to some special variety?
I'm only teasing a little. It's a specific sort of sunflower (safflower is also available in high-oleic) and sunflower oil will either say "high oleic" or it will have a ton of linoleic acid in it.
I use high-oleic sunflower to make mayonnaise because it has a neutral flavor. If I ever deep fry again, which eh, that might happen, I'll use a blend of it and tallow.
https://www.sunflowernsa.com/oil/High-Oleic-Sunflower-Oil/
It’s interesting!
What changed, and when?
Unlike tobacco, none of the researchers responsible for this calamity have been censured, sued, or otherwise suffered negative consequences. They are, for the most part, still in power, and research is conducted under their auspices.
Does this mean they're wrong about linoleic acid being healthy as well? No, not inherently, but it does mean that it's worth looking elsewhere and drawing your own conclusions.
However, all nutrients, including all essential nutrients, have a range of daily intakes within which they are healthy, and when eaten in much greater quantities than the upper limit of that range they become unhealthy, or even dangerous.
For example a too low selenium daily intake can cause illnesses, but eating selenium only a few times more than the maximum recommended intake can cause a severe poisoning.
That is true also for linoleic acid, in moderate quantities it is very healthy, in too large quantities it is unhealthy.
Until the last few centuries, it was extremely unlikely for anyone to be able to eat too much linoleic acid. It was possible to do that if one would have eaten huge quantities of, for example, pine nuts, poppy seed paste or walnuts, but all those were quite expensive so most people would not have been able to buy enough of them, much less eat enough of them, to suffer from that.
That changed especially since the 19th century, when the industrial production of edible oils began to provide large quantities of cheap vegetable oils, like sunflower oil and many others, which have a very high content of linoleic acid.
These cheaper oils have replaced the traditional olive oil and also the animal fats in most applications, which resulted in a greatly increased consumption of linoleic acid.
So for most people, now it is more likely that they might eat too much linoleic acid, than it is that they might eat too little linoleic acid.
But I don't think there are any dangers to poly unsaturated fats other than them easily turning into trans fats, so as long as factories are banned from making them into trans fats it should be fine. Or really the opposite, poly unsaturated fats are the healthiest fats, omega 3 and omega 6 and so on belongs to this group, just be sure to treat it carefully and don't let it turn to trans fats.
Here's the British Heart Foundation:
> Contrary to some of the reporting on this issue, cutting saturated fat doesn’t necessarily mean lowering all fat. We all need some fats in our diet and, over time, the very low fat diets recommended in the past have been put to one side as our understanding of the effect of this nutrient has developed. So, current guidance tells us to switch from saturated to unsaturated fats rather than cutting the fat completely.
> However, it is still important to talk about processed foods and what is in them. A lot of the food we eat is pre-prepared, and while sometimes the processing is as simple as canning tomatoes, processed foods also include foods like ready meals, sweet treats or processed meats where food manufacturers can alter the amounts of different fats, salt or sugar.
> As with our diets, when one thing goes out, something else will take its place. The concern is what saturated fat is replaced with when it is removed. Replacing saturated fat with refined carbohydrates, like sugary foods, or trans fats won’t improve our health, but replacing them with unsaturated fats seems to have a positive benefit.
> We also know that we are already eating too much salt and sugar on average so, while we welcome changes to reduce saturated fat in our everyday products, we also want manufacturers to be mindful of what they replace it with. As consumers, we still need to keep an eye on food labels to understand what is in the foods we are buying and make the best choices for ourselves, too.
Some of this was science not knowing they needed to check things, but a lot of it was media and industry groups trying to sell a product and running a with half truths that fit their narrative. there are a lot of old studies that we cannot/should not reference today at all because things we now know are important were not something science took care to control for.
Problem is good science takes years. Health authorities need to make recommendations today, and often for political reasons don't get the option to say I don't know.
The packaging of olive pomace oil can be deceiving though. If it seems suspiciously cheap, make sure that the label indeed reads "olive oil".
Turns out we were tragically wrong about that, causing tens, perhaps hundreds, of millions to suffer in old age and die prematurely.
So if I saw some mild evidence, like most nutrition scientists retiring, that the industry has reformed, that would be one thing.
As it is? I think they're lying, from Doing My Own Research™, but your mileage may vary. The important part is that you'd be a fool to trust the industry consensus with your own health.
After reading the books based on some internet persons suggestion I realized there’s controversy. Some say it’s junk science pushed by snake oil doctors others says it’s the next scientific revolution.
One fact remains, heart disease has gone way down and obesity has gone way up.
When I search for it, I just see studies about PUFA (polyunsaturated fats) benefits where they seem to always use canola oil (like swapping saturated fats for canola oil) to show benefits.
Yet overnight it seems like popular twitter accounts and podcasters have echoed seed oils = bad.
(I'm assuming in the above your goal is to keep PUFA low and n6/n3 balanced.)
There's also some animal studies w/ canola oil specifically that showed adverse effects, though I don't have them at hand.
Just looking at the characterization of fatty acids by unsaturatedness is omitting details which can matter -- the particular makeup of the fats (chain length -- a fatty acid w/ the same unsaturatedness can have varying effects on metabolism at different chain lengths; cis vs trans) as well as all the other chemicals that are in the oil, whether beneficial or harmful.
As one example, canola oil used to contain high levels of erucic acid, which is a 9-chain monounsaturated fat generally considered toxic. Over time the levels have gotten lower.
You might enjoy this video showing how canola oil is made:
Canola (Canadian Oil) or rape seed was used as an industrial lubricant oil. The first human lifecycle testing is now showing results. I avoid consuming it.
On a similar note, note, water is used as a lubricant, an industrial cleaner, an industrial solvent, and has strong corrosive properties. Too much water consumption can cause death.
https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthPro...
The page you link to say says:
> A deficiency of essential fatty acids—either omega-3s or omega-6s—can cause rough, scaly skin and dermatitis [5].
Then when we go look at [5] we get:
> Institute of Medicine, Food and Nutrition Board. Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids (macronutrients). Washington, DC: National Academy Press; 2005.
That's not actual data.
Presumably the reference intakes are based on some sort of data (would take some digging to find out, since it's incoveniently not hyperlinked) -- I might speculate it's based on exactly the 1929 Burr study that Peat is arguing was mistaken.
Hard to know though, without some digging.
Do you think PUFA is essential because it's what the NIH tells you, or because of specific experiments that have been done which demonstrate it?
If you had read the entire page that I linked you would have seen that
Do you think biochemical research into these pathways just stopped in the 1930s?
Usually if someone does this, I take it as an indication of arguing in bad faith, and give up on the conversation, but in this case I assumed good faith and scanned your link for the section that seemed relevent to your claim.
Anyway:
> Signaling molecules such as endocannabinoids are constructed from specific essential PUFAs, that combined with our cells swapping out different fatty acids to alter membrane fluidity
No dispute there...
> we literally lack the enzymes to construct them
...or there.
> tell me that we do need them
But you can't conclude that! You're still missing a demonstration that not being able use PUFA in these ways would lead to pathology.
And if it does, then what is the minimum level of PUFA consumption needed to to avoid it?
As far as I know, those questions have not been answered.
That said, I do think you're probably right, on an intuitive level. Any traditional diet (or indeed any diet that incorporates whole foods) will contain some PUFA, so it would make sense we were evolved to function best with some PUFA in our diet.
But, at least per Ray Peat's claim, all experiments with diets claiming to show the essential nature of PUFA were manifestly defficient in other ways.
So it seems the claim has yet to be demonstrated, and remains somehwat uncertain.
https://www.the-nutrivore.com/post/a-comprehensive-rebuttal-...
The conclusions is:
"In conclusion, vegetable oils appear to be a health-promoting addition to the diet, and seem to offer a range of health benefits and little to no apparent health risks to the general population. However, one should exercise caution when navigating the current food environment, as vegetable oils are included in many foods that are not particularly health-promoting. If one chooses to consume vegetable oils, it would probably be wise to integrate them into a healthy eating pattern in ways that do not promote the overconsumption of calories. Some possible healthy ways to include vegetable oils in the diet could be in the form of salad dressings or as cooking oils for sauteed vegetables."
Omega-3 is crucial to health, and the very middle-mainstream of nutritional science talks about Omega-3/6 ratios, the more extreme claim is that the ideal ratio is infinity: while there's some amount of Omega-6 we can digest without health consequences, there's no advantage to doing so relative to consuming none at all.
What about olive oil? It is not seed oil but does contain unsaturated fatty acids. Would it be considered safer than seed oils?