I looked into food sources and even bought a jar of capers which have the highest level of quercetin of any food. Come to find out, I would need to down a few jars a day to get to the levels in supplements, 500mg. That would be like 200% RDV for sodium though.
Wikipedia says 234mg/100g. A serving is 2 Tbsp which is 5g according to the label on the jar. It would take 40 Tbsp to get to 100g of caper to give you 200ish mg of quercetin. I prefer natural sources for vitamins but in this case, a 500mg capsule looks pretty good.
I suppose you could make a super salad, w/capers/kale etc and drink some red wine with it and get fairly close. Might have to be two of your meals every day.
I agree,Onions and apples and blueberries have them, just include these things in your food unless you’re feeling sick. You can add Quercetin supplements if you want to bring the total quercetin amount up. It just healthy eating, no prescription required. Unless you are sick do you even need a full dose? Maybe hold onto the Duvet 1.87% for when you don’t feel well I suppose.
https://www.vitacost.com/vitacost-quercetin-bromelain-120-capsules
Note that the first article mention Viking Aronia as being high in quercetin and antioxidants. Not a great taste, but its healthy. Its a berry bush that you can grow without much work, mostly keep the grass and other plants from surrounding it and give it sun. Not tasty so people will not be filching it, birds avoid it unless they are migrating and need to eat. It stores and freezes well. I think Diana in Wisconsin has some bushes.
https://www.medicalnewstoday.com/articles/320610#nutritional-information
(I don’t make any money from either of these sites.)