Q&A: Are only natural oils or butters prone to oxidation? Are water soluble ingredients? How can we protect these ingredients?

In the monthly Q&A, Noémie asked, Hi Susan, I’m a new subscriber and I love your work. I’m a beginner and I have a quite basic question : why only natural oils/butters are prone to oxidation ? If I well understood, oxidation occurs on double bonds in hydrocarbon chains, but don’t esters (derived from natural fatty…