I was searching for a list of supplements/acids/peptides, etc., derived from Vit B (I'm allergic to certain forms) that I should avoid or that might be causing my current allergic reaction (asthma, runny nose) when I found this post. I've had 3 variations of COVID19 (I'm such a lucky lucky girl) along with a host of other issues from birth. What I've learned: aging complicates sensitivities, combining different foods and supplements, herbs, even seasonings (example, say you just started liking and eating a particular ethnic food that uses a different blend of spices and herbs than what you usually eat...) can also spark new allergies and sensitivities. As suggested above, a very simple diet of whole foods--whole blandish foods, with minimal amounts of seasonings is a good idea. Nothing processed or aged. Do a search for two-week allergy test diet. I can't remember what all is in it, but no corn, nothing with artificial preservatives or additives--(including "health" foods--there are a ton of things that slip through the cracks and still meet the requirements for labeling), certain legumes, and of course, processed sugar, etc. It's really stressful if you eat out a lot trying to find things you can eat, so it requires a commitment on your part to follow it, but it's only two weeks out of your life, and it's a DIY, so no cost except the groceries. Wheat products (but rice and rye are allowed) are a no-no... Then you slowly start adding things back in, one at a time, every three days or so for another two weeks (at the minimum). Keep a record of it. Be sure to check with your doctor first, especially if you do have health issues of any kind. It will give you an idea of the more obvious allergens or sensitivities. Just to make this all more of a mess, there is a ton of misleading information out there, especially concerning health. Covid just made everything a lot harder. I temporarily lost my sense of taste and I'm just getting it back. The best place to start is to become an informed consumer and patient; the Internet doesn't make that easy because as I said, there's a lot of misinformation, so you'll have to do due diligence. Then, talk to your doctor or healthcare practitioner. Use common sense. Best wishes.