I'm a 40 year old physician who has a severe reaction to consuming annatto. If I eat any significant amount, I have the onset of severe vomiting and diarrhea roughly 12 hours later, which then persists for 12-24 hours. I don't have any classic "type I hypersensitivity" symptoms such as hives, just a severe delayed gastrointestinal symptoms. I've managed to effectively avoid annatto since the age of 4 or 5, except for rare exposures every 3-10 years since the age of 4 or 5. I've only recently learned about annatto and concluded that it is the additive that explains my intolerance to certain foods.

Here's my brief story. At a very early age, about age 5, I refused to eat cheese since I insisted it made me sick. My mother tells a story that she didn't believe this, had me eat some, and recalls "sure enough, he threw up!" However, I could drink milk and other dairy products without problem. As a teen, I figured out (the hard way) that white cheese like mozzarella didn't cause a problem, but yellow cheese did. So I continued to avoid yellow cheese, knowing that it made me ill. Everyone around me thought my aversion was odd, and I suspect many people thought it was my imagination. I would accidentally eat something with yellow cheese added every 5-10 years, get severe symptoms, and this would reinforce my belief that I really did have a "physical" intolerance.

I learned of annatto a year ago, and finally my reaction made sense. This connection was reinforced when I got sick a couple of weeks ago, and I assumed it was the flu since I had not eaten cheese. My wife looked in our refrigerator, and sure enough we had some orange yogurt with annatto added. I had eaten two the night before.

I'll also mention that at baseline, with no annatto exposure, I tend to have symptoms consistent with mild irritable bowel syndrome. I've never bothered to ask for a diagnosis, and am used to living with it. So, my pattern hasn't been chronic IBS symptoms with chronic annatto exposure, but severe reactions when I get exposed very rarely. – Physician, USA