everybody is different - for example some mums can bf through a whole pregnancy and not lose their supply too much - whereas I went dry at 7mths. Was soooo blardy annoyed about that. Others can run marathons and still feed their kids and express extra. You wont know till you try but do it slowly. and if your supply does get affected you then can decide to either back down or continue with more meds/pumping etc.
you can add flaxseed oil to foods (use it in baking instead of butter/cooking instead of olive oil etc) and chia seeds can be added to porridge/oats/biscuits/slices etc.
Lactation biscuits I think have both in them.