The PUFA in grapeseed oil is linolenic acid (~75%), which this specific study ruled out as the cause of the genetic expression changes observed in high-fat diets with soybean oil.

FTA:

>One additional note on this study — the research team has not yet isolated which chemicals in the oil are responsible for the changes they found in the hypothalamus. But they have ruled out two candidates. It is not linoleic acid, since the modified oil also produced genetic disruptions; nor is it stigmasterol, a cholesterol-like chemical found naturally in soybean oil.

Huh, I did actually miss that. Thanks for pointing it out. Linoleic acid isn't fully accepted as being healthy, so it was an easy assumption for me to make.

My understanding of linoleic acid is that it got a ton of good press as a result of the blowback from the discovery that we were basically poisoning ourselves with trans fats. So it wasn't really that we know PUFAs / linoleic acid are good, it's just that we know they're an existing alternative to something very bad.

Example random study link that points out some of the unknowns around linoleic acid: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5492028/

There's a difference between a dietary supplement being overhyped, and it actively causing harm.

Unknowns != Linolenic acid is harmful; and from this study it's at least obvious that it doesn't change genetic expression in the thalamus.