Dr D’Adamo, his father (also a doctor), and many other researchers have found significant trends in allergies, food tolerance, and disease susceptibility which are unique to each of the four blood types: A, B, AB, and O.
In Japan, people almost always know their blood type, and ascribe different tendencies to each one. It is not unusual for a job posting to specify a certain desired blood type in applicants. Some of the Japanese ideas re; the psyche of the different blood types is further quantified in D'Adamo's thoroughly researched books.
In my practice, I had 12 people in a row with GI symptoms that were along the lines of IBS, IBD. They had bloating, indigestion, and general gut misery, in varying degrees.
They also all happened to be type O! Now, what are the chances of that?
Type O's do have many advantages over other blood types, but they have a royal weakness- grains according to D'ADamo, and possibly other starchy foods, according to Elaine Gottschall, who wrote the Gut Reaction. More on her on the Gut/ Digestion page which I am going to build, promise!
Anyway, getting back to these 12 people- they all improved greatly by following their correct blood type O diet, and by taking some supplements I had discussed with them.The two worst ones were on heavy prescribed drugs, including strong anti-inflammatories. Guess what? In less than a week, they got off all their pills, and felt wonderful!