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Recently (Dec 2017), it came out in Nature magazine that chronic use of canola oil can lead to memory impairments and even Alzheimer's. So far I had been reading mostly good things about it, also given its high smoking point, SFA/MUFA/PUFA ratios and Omega-3 content, it seemed ideal to use for frying.

Does anybody have any meta-analysis on the effects of canola oil?

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    I think your last sentence is a question for the cooking exchange and should be deleted from this question.
    – Carey Gregory
    Jan 3 '18 at 15:16
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    @CareyGregory done
    – AA_PV
    Jan 4 '18 at 7:40
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Fat rodents are slightly dumber than lean mice?

The Effect of canola oil consumption on memory, synapse and neuropathology in the triple transgenic mouse model of Alzheimer’s disease (2017) is an interesting result, to be sure. If rapeseed oil is indeed responsible for the effects observed we should definitely get to know that and react to that.

But it is a very preliminary result in one animal study, eagerly picked up by 'journalists'. Given the small effect of a study so subpar in design that one has to wonder why that relatively prestigious journal did not enforce higher standards for what has been published. Reading just said article I wonder how a simple replication could be reliably constructed from the limited information given. The section "Materials and Methods" was either shortened severely or the design of that study was – naive – to stay polite.

Temple University again greases the clickbait machine with canola oil study

Scientists should be lauded for investigating health claims used to a market a product. But when preliminary findings are reported to the public without appropriate context, that’s a problem. […]

Only the Inquirer warned readers about relying on a mouse study, stating in the second paragraph: “The results should be viewed with caution because what happens in mice often does not happen in people.” But that warning came only after baiting readers with the overreaching headline.[…]

The Inquirer’s story also contains information that’s not in the news release and does serve to temper some of the hype. It reports that the senior investigator “considers the study a ‘red flag’ for canola oil users, though he would not tell people to stop eating it,” that he plans to experiment with different fats and doses “to see how much is needed to induce brain changes and whether changes are reversible,” and that he acknowledges not knowing why canola oil and olive oil might affect the brain differently.

An even nicer analysis than in the compressed comments on Nature is on Medium:

No Evidence of Canola Oil Causing Alzheimer’s and Dementia
Sensational Misinterpretation of Published Data Creates Concern where None is Warranted

Overall. When looking at this paper I see a good lab with competence and expertise in the area performing a test on a small number of mice, where they give standard lab chow and lab chow containing significant amount of canola oil. The effects seen cannot be directly attributed to canola oil per se, but to oil consumption, or increased calories in the diet, or just being overweight. Obesity is associated with at least certain forms of AD, so seeing specific markers and mild impairment in an AD mouse model is probably not surprising.

It may very well turn out that unidentified or untested for toxins, pollutants, pesticides, mineral oil residues or who knows what in the oil tested elicits undesirable effects. Erucic acid is perhaps not the only poison naturally found in rapeseed that makes it less than ideal as 'the standard cooking oil'. That paper in question doesn't tell and does not allow to infer any such conclusion either way. It may be an important clue, an honest error or just junk.

In the meantime, the positive evidence in favour of using rapeseed oil seems to have the majority:
Lin Lin et al.: "Evidence of health benefits of canola oil", Nutrition Reviews, Volume71, Issue6, June 2013, p 370-385, DOI:

Canola oil‐based diets have been shown to reduce plasma cholesterol levels in comparison with diets containing higher levels of saturated fatty acids. Consumption of canola oil also influences biological functions that affect various other biomarkers of disease risk. Previous reviews have focused on the health effects of individual components of canola oil. Here, the objective is to address the health effects of intact canola oil, as this has immediate practical implications for consumers, nutritionists, and others deciding which oil to consume or recommend. A literature search was conducted to examine the effects of canola oil consumption on coronary heart disease, insulin sensitivity, lipid peroxidation, inflammation, energy metabolism, and cancer cell growth. Data reveal substantial reductions in total cholesterol and low‐density lipoprotein cholesterol, as well as other positive actions, including increased tocopherol levels and improved insulin sensitivity, compared with consumption of other dietary fat sources. In summary, growing scientific evidence supports the use of canola oil, beyond its beneficial actions on circulating lipid levels, as a health‐promoting component of the diet.

Concerning Alzheimer's directly, it is even suggested that rapeseed oil might be more of a positive factor than a danger, because of their vitamin E and fatty acid contents.
Michelle Walters et al.: "Role of Nutrition to Promote Healthy Brain Aging and Reduce Risk of Alzheimer’s Disease", Current Nutrition Reports, June 2017, Volume 6, Issue 2, pp 63–71, DOI

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