I recently learned that I am allergic to rutin, a bio-flavonoid that is found in citrus.....actually in almost all fruits and vegetables that taut being an antioxidant, as well as tea. Tea is very high in rutin, especially green tea. It took me decades (I'm 50) and numerous allergy specialists to figure this out. Imagine the hell I put myself through while trying to exist on a vegan diet, thinking it was a good thing. It's a very rare allergy (last statistics suggested that only 15% of the worldwide population have it) so there is no research/info (so no money in it) on it. If anything, when you research RUTIN, I usually only get ads on where I can purchase it as a supplement.