Type O
The first known blood type was Type O, which dates as far back as the ascendance of Cro-Magnons and remains today as the most common blood type worldwide. Type O, which we call “the hunter”, has a strong and ornery immune system and a hearty digestive system. The strength of the Type O immune and digestive systems ensured early survival because meat was the primary food source. The Type O has an extraordinarily high stomach acid content, capable of drawing the most nutrients from meat and efficiently assimilating such a protein heavy balance of foods.
You might say that Type Os were the first humans to eat on the run. They hunted where they were led by their prey, killed it, consumed it, and moved on. However, over time, the vast herds of available game began at last to thin. As the human race continued to evolve, the desire for survival forced many to learn the skills of growing and preserving a food supply that would protect against famine. This new system demanded that humans remain in one favorable geographic area and create settled cooperative societies that would devote themselves to sustaining the agrarian cycle. Living in communities not only demanded new social skills, it also gave rise to new diseases.
Type A
Type A, which began to gain prominence between 25,000 and 15,000 BC, differentiated its immune system from that of Type O to fight off infections and bacteria that were decimating the collectives, while the Type A digestive system adapted to a diet that was able to meet the body’s need for proteins derived primarily form plants and grains. At the same time, lakes, rivers, and seas provided a bounty of fish that incorporated yet another abundant protein source into the human diet. We refer to these new Type As as “the cultivators”.
Type B
Type B began appearing between 15,000 and 10,000 BC, as the growing tide of humanity spread beyond the range of the first Type O hunters and moved out from the settles agrarian Type A communities-one reason we call Type B “the nomads”. Century after century, enormous tribes traveled across the endless landscapes of a still primitive and ever changing world, surviving on the meat and dairy of the cattle, goats, and sheep they herded as well as on whatever they scavenged along the way. Because Type B incorporated so many of the immune and digestive system characteristics of Type O and Type A, they developed a system more balanced and tolerant than that of either of the previous types.
Type AB
For most of our history, there have been three blood types, and then, approximately ten to fifteen centuries ago, Type AB, still very rare emerged. We often call Type AB “the enigma”, because it isn’t entirely clear what stimulated this latest blood type adaptation. Perhaps the full evolution of Type AB is yet to come. What we do know is that it combines most of the strengths and weaknesses of both Type A and Type B. The Type AB immune and digestive system is more complex and quirky than any of the others, which is both good and bad. The good resides in its wide range of immune and digestive responses; the bad in its incorporation of the frailties and vulnerabilities of both Type A and Type B.