Submitted by: Josh Hall, Muncie, Indiana

I am a big fan of NHE. I was introduced to NHE while attending a class at Ball State University, luckily it was required reading for the course! I have read it several times since and see no mention of blood type and nutrition. I was intrigued after reading an article that claimed different blood types occured as a mutation due to overpopulation, disease, migration and dietary changes thousands of years ago. Resulting in type A and B blood. The article also claimed type A people could better absorp and tolerate grains ie. carbs. due to a shortage of protein several thousands of years ago. I was wondering what your thoughts were or if you have done any research on this subject.

Thank you for your letter, and please give my best regards to everyone at Ball State, a great American university.

NHE makes numerous qualifications based upon biochemical individuality, but does not delve with particularity into that line of inquiry. Blood type affords insight into bioindividual characteristics through group differentiation, and as you suggest, correlates have been posited between blood type and dietary predisposition. This would apply not only to macronutrition as noted in your letter, but to micronutrition as well. Specifically, “mutation due to overpopulation, disease, migration and dietary changes thousands of years ago” may result in certain populations adapting to scarcity of certain vitamins or minerals by acquiring a preferential ability to absorb or retain that nutrient. Conversely, the genetic downline of populations lacking such ability due to historical abundance would suffer graver consequences from present deficiency.

To the extent one blood type better tolerates carbohydrate, it represents a gradation on the continuum of carbohydrate moderation not a departure from it. The advisability of a cyclical low-carb diet with scheduled carb-loading is not subordinate to blood type. Accordingly, while there is evidence of a relationship between blood type and optimal nutrient intake, which can be useful for fine-tuning one’s diet and supplementation regimen, this should not be permitted to obscure basic universal principles of human nutrition. Given the technology-driven changes that have occurred since the agricultural and later industrial revolutions, no view of the human evolutionary diet could reasonably maintain that bread or cookie dough consumed frequently is in any meaningful sense tolerable irrespective of blood type.