Ok, I think I know the kind of person you are talking about- maybe a Food Babe following type of lady? Who doesn’t eat things with food coloring or preservatives, who reads labels and knows not to buy bread with dough conditioners in it? Who would never eat chocolate flavored syrup but might have pure cocoa sprinkled on her latte? Organic fruits only please? Yes, I know a lot of ladies like that.
The route to take, imho, is to slowly back into the discussion. To agree carefully and thoroughly on the food intake first, using phrases like “we are what we eat” and “every bite of our food affects who we are and how we feel”. And don’t think I’m being sarcastic with my comments- I actually agree with this! My son is gluten intolerant and my husband is allergic to half the world… we eat very, very carefully. I read labels and mostly eat from scratch.
Anyway, once she knows you are being sincere, the conversation can carefully blend over to “other things that can poison us”… And here you might have to come up with what she can tolerate or be interested in. Electromagnetic radiation? tap water with dregs of who knows what in it? Air pollution increasing asthma incidence yearly? etc. and then casually slip in, “and I’ve read that the unnecessary prescribing of medications is actually very harmful as well…fill in more info…long term use of however you want to carefully say it…”
Perhaps you can have a decent conversation with her. I hope so- but in the end, no one can change her mind except her, of course.