CATE SHANAHAN: An oil's toxicity comes chiefly from polyunsaturated fatty acid (PUFA) oxidation. PUFA oxidation creates toxins, that's basic organic chemistry

Reposting the below by @jeremykauffman because it's reflective of some common misperceptions that I want to debunk. (And because @drdrew asked me to chime in.)

Here are the 2 common misperceptions.

1) Seed oil toxicity derives from omega-6. Omega-6 is a nutrient, so this is… https://t.co/ltgoPppXPV

— Cate Shanahan, MD (@drcateshanahan) November 17, 2024

Reposting the below by

@jeremykauffman

because it's reflective of some common misperceptions that I want to debunk. (And because

@drdrew

asked me to chime in.) Here are the 2 common misperceptions. 1) Seed oil toxicity derives from omega-6. Omega-6 is a nutrient, so this is mostly incorrect. 2) Dietary omega-6 drives inflammation. That’s possibly true under extreme circumstances but it’s not the reason seed oils promote inflammation. Here’s the deal. An oil's toxicity comes chiefly from polyunsaturated fatty acid (PUFA) oxidation. PUFA oxidation creates toxins, that's basic organic chemistry. And in the body PUFA oxidation also promotes inflammation, that's basic biochemistry. When you expeller press olives you make virgin olive oil. That’s edible. When you expeller press canola seeds, you make a mess. The crude canola oil is NOT edible. It has to be extensively refined and the refining process removes many stabilizing nutrients/antioxidants/vitamins. It also oxidizes and isomerize alpha-linolenic fatty acids (an omega-3) and generates toxicity. That particular fatty acid oxidizes into toxins faster than linoleic (an omega-6). These toxins are present in parts per million amounts, so they pass quality controls, but they multiply over time becuase the oil lacks the stabilizing factors nature puts into the seeds to prevent PUFA oxidation. The toxins multiply because they can attack the PUFA and create more toxins. Let’s also consider some history: We're only eating the Hateful 8 seed oils because the AHA scared us into it with the claim that they can prevent heart attacks. That claim has never been supported and even the AHA is somewhat backing off from it by saying things like olive oil is better but these are not all that bad. The AHA misled us. Now we’re eating hundreds of calories per day and everyone is unhealthy. That’s not a coincidence. We can’t trust the AHA’s advice about fats! And I wouldn’t trust anyone who has not called out the AHA for misleading us.