I found Eat Right For Your Type by naturopath Dr. Peter D'Adamo a most fascinating book and I heartily recommend reading it. This is not another diet book, though it does discuss foods that can help one lose weight or gain weight based on one's blood type. D'Adamo makes sweeping claims about the types of food and drink to consume, exercises to do, supplements to take and avoid, and medical strategies to apply based on blood type. He and his father have many years of clinical experience to support his claims and he draws on research into the biological history of humans as well as current laboratory evidence for additional support. Though I won't do his book justice in this brief paper, I will try to touch on some highlights related to diet.

D'Adamo attempts to make the case that people with each of the different blood types do best on a particular type of diet. His argument is that type O blood, the oldest and most common blood type, does best on a meat centered diet. The earliest humans were hunter gatherers and their blood was "optimized" for this lifestyle. Some 20,000 years ago, type A blood emerged as an evolutionary response to some humans adopting an agrarian lifestyle. People with type A blood, according to D'Adamo, fare best on a vegetarian diet. Type B blood first developed about 15,000 years ago, as a blend of types A and O when people moved to less rich farmland and had to strike a balance between eating animals and their crops. D'Adamo suggests people with type B blood have the most flexible dietary choices. The newest (about 1000 years old) and rarest (2-5% of the population) blood type is AB which arose from the interbreeding of people with type A and type B bloods. They do best on a cross between diets geared for people with type A blood and those with type B.

In my mind, D'Adamo makes a compelling case, though there are a few "stubborn facts" which are not addressed. First, I have heard (but been unable to confirm) that gorillas (and likely other apes as well) share blood types in common with humans. If this is so, one would think the common type would be O and that it comes from a common primate ancestor. However, gorillas are vegetarian. If what I've heard about gorilla blood types (from a gorilla expert on TV) is true, it doesn't seem to fit with D'Adamo's theory.

Second, in many broad population studies (in which blood type was not considered an important parameter to track), humans generally fare better on vegetarian diets. Since type O blood is the most common and D'Adamo claims people with type O blood fare best on meat-based diets, there seems to be conflict between D'Adamo's theory and the results of these many and varied studies. I hope future broad population diet studies include an analysis of the effect of blood type on the studies' results.

Third, the claim that our oldest ancestors were largely carnivores doesn't fit with our physiology. Evidence for humans as, at most omnivores, can be found in our physiology when compared with true carnivores (such as dogs and cats). Compared to carnivores our teeth are not suited for ripping flesh (we've mostly grinders and short canines and hence resort to cooking our meats and using utensils to cut them), our stomach acids weak, our intestinal track too long (meats in them tend to linger and putrefy), and our "claws" ineffective at holding and tearing prey (which is why we depend on tools, weapons, or domestication to "hunt.") The species with which we are most closely related, the other apes, are largely or entirely vegetarian (whatever their blood types).

A food allergy test based on a blood sample we had done for Eric (who has type O blood) brings up a fourth stubborn fact: Eric tested allergic to meats. D'Adamo likely would claim that there was something in the meat, a chemical or hormonal residue common in the meats Americans eat, to which Eric is allergic and not the meat itself. If that claim were correct, it doesn't undercut D'Adamo's main thesis but it also doesn't help us identify the specific allergen to avoid plus it is very difficult to get residue-free meats.

Putting aside the "stubborn facts," let us for the moment assume D'Adamo is largely correct. Unfortunately for my family, we all have type O blood. We are also vegans. According to D'Adamo, our physiology is suited to eating meat and fish and largely avoiding nearly all grains, cereals, nuts, beans, legumes, and dairy products. His listing of "foods to avoid" (other than dairy products) make up the major part of our diets. The foods on which he claims our diet is to be centered are foods we avoid. There is personal evidence to support D'Adamo's theory. Our acupuncturist has diagnosed me as having a weak digestive system and Missy as having a thyroid problem--these are two problems D'Adamo predicts for type O's that do not follow a type O diet. If his theory is correct, it creates a dilemma for us.

We made the ethical choice to become vegetarian even when, at the time, we assumed we would be sacrificing our personal health. We had been schooled in the four food groups and thought it unhealthy to avoid eating meats and dairy products. We subsequently learned that a vegan diet was a healthier diet, which gave us greater comfort and confidence in our dietary choices. Now we learn it may be the case that for us it is not a healthier choice. Here is a sense of the dilemma that creates for us. Ethical vegans make little distinction among the respect we give to individuals based on their species. We are no more inclined to eat non-human animal flesh as human animal flesh. Imagine that you are told you must eat human flesh in order to maximize your health. Would you do it? You may also imagine that eating human flesh is a cultural norm but assume the production of human flesh for the masses involves enormous pain and suffering for the people who are slaughtered at a young age for their meat. That's the nature of the problem we face. We are too aware of and sensitive to the plight of non-human animals and their abuse by human animals to knowingly contribute to that abuse. Our die has been cast. If D'Adamo is correct, we will find an ethical workaround to the "need to eat meat."

An additional dilemma for Missy and I as parents: what about the foods we feed our son Eric? Do we have the right to avoid feeding him the appropriate foods for his blood type (assuming that D'Adamo is correct) based on our ethical choices? Parents (we think mistakenly) assume they not only have the right but the responsibility to instill their morality in their children. Would that apply even at the cost of physical health? (Sometimes the practices of Christian Scientists result in the unnecessary deaths of their children.) Eric, as most children, loves nature and being friends with all living creatures. Unlike most children, Eric doesn't live with the contradiction of eating his friends (the cooked and unrecognizable pieces of which are given him and also consumed by his beloved parents). When asked, Eric tells us he would never eat meat. As parents, we try to demonstrate the rationale behind moral choices and their implications. We see it as Eric's responsibility to craft or choose his own ethical system without our limitations.

D'Adamo's book has what I think is a serious shortcoming. It doesn't address the ethical and environmental ramifications of a meat-based diet for most of the world's population. If we strove to feed people foods on which D'Adamo claims they fare best based on blood type, there would be too many people eating too high on the food chain. It could not be sustained. The abuse of non-human animals in factory farms just to sustain the meat-based diets of Americans is staggering and unconscionable. Large populations combined with eating high on the food chain is also the root cause of many of our environmental problems and impending problems.

There is one other important consideration that D'Adamo does not address in his book and that is life expectancy. We know from broad population studies that humans who follow a vegetarian diet tend to live longer than those who follow a meat-based diet. (As noted earlier, these studies haven't in the past controlled for blood type.) Why might this be so? If one thinks about our oldest human hunter/gatherer ancestors, those with type O blood, the lifestyle is one in which physical strength and stamina is important. Once one moves beyond the childbearing age and one is no longer able to carry one's weight in hunting, one becomes a drain on the tribe. One is expendable from both an evolutionary and tribal perspective. For humans, eating meat may mean burning bright and dying young. As it feels good to "burn bright," people with type O blood may not look to see the short runway they are rapidly consuming along with the meat.

Agrarian based communities are those in which richer cultures develop. In these populations, the elderly are valued because they embody the traditions, rules, and stability the society needs to thrive. Since the physical work of farming is less intensely demanding (compared to hunting), it is easier to provide for one's self into an older age. Plus it is easier for the community to acquire food surpluses to provide for those who cannot provide for themselves; particularly the elderly who are now valued societal contributors. For humans, being vegetarian seems to mean positioning oneself for a long life.

D'Adamo has a website that includes discussion boards. We culled the following information from it for people with type O blood who want to largely follow D'Adamo's recommendations but who are vegans and wish to remain so (I am not personally endorsing these statements, just repeating them):

Supplement with the amino acids L-carnitine and taurine, magnesium, brewer's yeast, vitamin B12 (methylcobalamin is best type), and the ayurvedic herb "coleus forskolii" which acts as a source of cyclic nucleotides (cAMP).

Stay away from wheat, corn and dairy and try not to rely on carbohydrates (bread, pasta, bakery products, etc.) to fill up. Moderate portions of rice with blood type O friendly beans and lots of nuts and seeds will be your main protein sources. Tempeh stirfrys are an OK choice, but tofu is best used in moderation.

© 2000 frantzml@juno.com