From what I’ve read, heat processing flax lowers the Omega 3 and some of the other nutrients available in it.
Does roasting, boiling, light-frying (in coconut oil), heat processing nuts and seeds with high Omega 6 contents (like sunflower seeds, pumpkin seeds, peanuts, almonds etc) lower the Omega 6 in them? If so, is this a reasonable way to eat those kinds of nuts and seeds, while maintaining a balanced Omega 3:6 ratio?
The omega 6:3 balance is nonsense. Both omega 6 and 3 are beneficial. Do not limit either in an attempt to change the ratio between them. That ratio is most likely a proxy for consuming processed junk food
> Does heat processing nuts/seeds lower the Omega 6 in them, like it does for the Omega 3 in flax?
LA is more thermally stable then ALA but ALA is generally stable enough that if you are not using high heat cooking it’s not a huge concern. DHA & EPA are the larger issues and why low temperature cooking for oily fish is a good idea (beyond that it tastes better).
Temperatures <~200o losses of LA & ALA are insignificant. Higher temperatures you will generally loose ALA faster than LA.
> From what I’ve read, heat processing flax lowers the Omega 3 and some of the other nutrients available in it.
It depends on the technique. Industrial production uses a bunch of tricks to avoid this problem.
One thing to keep in mind here is the fats are almost entirely in triglycerides so even though their component fatty acids may not be thermally stable you have to break them from those to actually degrade them meaningfully. While you start to see some degradation beyond 200o even oils with poor thermal stability wont start really running into issues until 500o. The smoke/burnt flavor when you heat an oil is not the fat burning but other compounds in the oil.
> Does roasting, boiling, light-frying (in coconut oil), heat processing nuts and seeds with high Omega 6 contents (like sunflower seeds, pumpkin seeds, peanuts, almonds etc) lower the Omega 6 in them? If so, is this a reasonable way to eat those kinds of nuts and seeds, while maintaining a balanced Omega 3:6 ratio?
If you are concerned about your ratio you shouldn’t be using coconut oil, its mostly saturated fat and LA with no ALA at all.
The easiest way to improve your ratio is to eat more ALA, EPA & DHA. Walnuts (and walnut oil) is fantastic as its at 4:1 already. Flaxseed is the best cooking oil followed by canola. Nothing that is not from the ocean beats flaxseed oil and canola beats most land based sources.
Switch out land animals for oily seafood and shellfish.