Hi Everyone,
A simple sounding question that has been giving me trouble for a while. Hopefully someone on here can explain it to me.

I understand that Polyunsaturated Essential Fatty Acids are less stable than Monounsaturates, which are less stable than Saturated fat - which in turn increases the risk of the oils going rancid as oxygen infiltrates the carbon bonds that are not saturated with hydrogen atoms. We all know rancidity is bad.

I dont understand the process that occurs due to cooking regarding polyunsaturated oils. I would assume the heat alters the oil in some way ? -if so, is this alteration beneficial or harmful to human health ? I would assume the very fragile nature of polyunsaturates would mean that they have a very low 'smoke point' - after all, there has been much discussion on cooking with olive oil (much more stable than fish oil) on this site.

Basically, how can cooking fish not alter the fish oils inside, the same way oxygen does when it makes the oils go rancid ?

Many thanks in advance for anyone that can solve this one for me - i hope there's a post somewhere i can be linked to .