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Comment by twanvl | Hacker News Reader

> The evidence for the harms of canola oil is still in its early days, but continues to grow. Research has linked it to: Memory impairment [1], Alzheimer’s risk [1], Cardiovascular disease [2], [5], [6], [8], Diabetes [2], Increased all-cause mortality [2], [6], [7], Metabolic syndrome [3], Decreased brain function [4], and Oxidative stress [5], [7].

Most of these references talk about how there is no clear benefit of vegetable oils over animal oils or how "chronic canola oil consumption" results in obesity in transgenic mice. That is not really the same thing as "growing evidence for the harms of canola oil".

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For completeness, I checked them all and the score is:

* Rat

* actually about cooking _in_ canola oil

* about switching _any_ vegetable oil to _less_ olive oil

* Rat

* actually about a different oil with quite different content of the active acid being trialled

* Rat

(Oh, and the article is written by a SEO marketer)

https://news.ycombinator.com/item?id=24090817 points out that rats, rather uniquely, cannot process erucic acid (part of canola oil) and the rat studies likely do not apply to most other mammals (including humans).

At this point, we should all just flag this article til it's gone. It's FUD

I'm curious of your actual hunch, are you actually skeptical that canola (and other industrial seed oils) are not harmful?), or just pointing something out about the evidence?

I read it as twanvl pointing out that there is a lack of evidence to support the article's claims.

I would be interested to know if these studies refer to low quality vegetable oils using a chemical process to extract oil. For example, in the UK, supermarkets sell cold-pressed rapeseed oil (canola oil in the US). The cold-press process is sold as making rapeseed oil as relatively healthy cooking oil.

Does cold-pressing rapeseed/canola seed turn it into a relatively healthy cooking oil (vs the expeller-pressed or chemical extraction process)?

The problem is the fats in those oils are very susceptible to oxidation and have low smoke points, they are never safe as cooking oils for this reason.

For cooking the best options outside of animal fats are olive oil and coconut oil, but of course olive oil is most versatile and better tasting imo.

Avocado oil is much better than olive oil, which has a low boiling point.

It's probably equivalent but the taste doesn't go with most foods, also it goes bad much easier which again suggests less stability.

If you're concerned about the taste of Avocado oil you may have just had poor quality oil. I've had some bad experiences, but the one from Chosen Foods (we have it at Costco in Ontario) is a very neutral oil with a high smoke point.

I don’t know where you’re getting this from. I use canola oil when pan-frying food and it stands heat better then most olive oils. The cold-pressed variety tastes like shit though (well, actually it tastes like canola which has a kale-like flavor that I find unappealing). The refined canola oil is perfect for frying.

Right, I think what he's saying is that you shouldn't use cold-pressed oils for cooking/frying. Cheaper refined oils are better for this purpose. Keep the fancy cold-pressed oils for salads, dipping, drizzling, etc.

Refined olive oil does have a slightly higher smoke point than refined canola/rapeseed oil, but for most home cooking purposes it's probably within the margin of error. Something like refined sunflower oil or refined avocado oil has a higher smoke point still.

Quoting this study https://actascientific.com/ASNH/pdf/ASNH-02-0083.pdf (note: I get an error opening the PDF)

> Extra virgin olive oil (EVOO) yielded low levels of polar compounds and oxidative by-products, in contrast to the high levels of by-products generated for oils such as canola oil.

But I formed my position from many other points, the degradation in public health in the USA has tracked perfectly with the switch from animal fats to seed oils for cooking (and other uses but frying is the worse offender)

Any idea where I can find that study? The link above is dead. I have been using Canola oil for frying because I thought it was a neutral tasting oil that didn't produce as many toxic compounds when exposed to high heat—vs olive oil which purportedly did produce them. Seems I've been misinformed.

Unfortunately no, the title is " Evaluation of chemical and physical changes in different commercial oils during heating", hopefully you can find it.

Here's an article that makes the same point with a great overview of the underlying mechanisms: https://breaknutrition.com/omega-6-fatty-acids-alternative-h...

It also tracks perfectly with increased calorie consumption.

So one potential explanation is that people are eating more, and then another potential explanation is that there is some as yet mysterious biological process whereby processing calories through some long extant metabolic pathways triggers changes in health.

It might be good from a culinary perspective, perhaps smoke point is irrelevant, I was thinking of what causes degradation of the fats when subjected to heat.

From memory the good stuff in olive oil is destroyed by heat (if you swallow olive oil and it's good quality, you get a distinct 'burn' at the back of your throat).

Also IME olive oil loses its interesting taste rapidly when cooked with, but others may not find that.

The smoke point of olive oil varies significantly from extra light to extra virgin. Extra virgin actually has a much lower smoke point than canola oil.

Give avocado oil a shot. Great smoke point, no real flavor. I am allergic to avacado somehow and the oil doesn’t bother me.

Most allergies are to a protein in the thing you are allergic to, and refined oils that have a high smoke point usually have all of that removed (or it would cause the oil to smoke.) I have a peanut allergy but can eat anything fried by a cheap restaurant in Sysco peanut oil while I have had a reaction to something done by a three star restaurant because they used unrefined oil (looking at you Manressa...)

Makes sense. Good to know, thanks.

> obesity in transgenic mice.

I definitely read this as "obesity in transgender mice" the first couple times and was seriously wondering if that was actually a thing.

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