After becoming convinced that my problems were related to annatto, my husband (a retired doctor) wrote this letter to a doctor at Yale University. You can see the entire letter by linking here:
Letter About Annatto to Yale University School of Medicine
Dr. Martin Floch, a doctor at the University, then wrote this article for the Journal of Clinical Gastroenterology:
Article entitled Annatto, Diet and the Irritable Bowel Syndrome
