ah, gotcha. Okay. If you give them just a teaspoon of oil occasionally - like 3-4x a week, that's really no problem. And i fyou get an oil like Udo's Choice (or is it Udo's Prime? I forget!) you can use that practically daily because it isn't just flax but other oils too.
Then the rest of their oils can be fish, cod liver (cod liver oil is a MUST), olive and coconut and you'll be doing really great!
The key with foods, since none are perfect, is variety and not overdosing. That way the body gets all the building blocks it needs and the anti-nutrient properties of one will be counter-balanced by another. Very few foods are like Soy, so imbalanced that the only way to balance them is to AVOID them.