On pestilence, diet, natural selection, and the distribution of microbial and human blood group antigens and antibodies
Charlotte M. Otten. Current Anthropology June, 1967 Vol.8(3):209-223.
In this article written by Otten, she raises the topic of some individuals poorer resistance against viruses or bacteria that carry antigenic specificities similar to those of their own blood group substances. The hypothesis of some of the writers she mentions, note that the 'closer the structural correspondence between ABH and microbial capsular antigens, the poorer the resources for resistance in the host.' Therefore, whether the individual carries the anti-A or anti-B antibodies, is a determining factor for some protection against certain categories of organisms. Blood group specificity is a characteristic of the entire organism rather than just certain parts of the blood stream. She then discusses several factors that help support or question the hypothesis of the relationship between resistance and blood types. One of these is the dietary factors of groups of people. It suggests that there are high A frequencies associated with meat-eating and high B frequencies associated with carbohydrate-eating. However, there is a problem that arises with this and that is the lack of information on aboriginal diets. In sum, there may be evidence that they may not be done with the idea of diet being a selective force in blood group frequency distribution. The next notion is that of antibodies, this is explained through a variety of experiments and studies. One is of gamma globulin secretion which may have a significance on natural selection. These antibodies must selectively defend the portals of entry against bacterial and viral invasion and that the selection must have a 'very specific dependence upon individual blood group character.' The final discussion is that of intestinal and gastric microbiota. This basically says that the intestinal flora can affect the organism's vitality and growth. It claims that a shift in diet whether it was a change from carnivorous to herbivorous content (or vice versa) has an effect on the composition of intestinal flora. She concludes with a discussion of the lactobacilli and its association with growth enhancing activity.
The commentators who wrote about her paper were for the most part supportive of her work and found it very interesting and the data she presented to be informative. Several of them share her opinion on the 'disapproval of the uncritical acceptance of the idea that infectious diseases have significant selective effects on certain blood group genes.' Most of the commentators had positive things to say about Otten's work and shared her views. They were impressed with the material that she presented, in addition to the likeability of her work; they also presented ways in which she could strengthen her argument and where information could be lacking.
Otten seems to be appreciative of the comments and suggestions that were pointed out to her about her paper. She also seems glad of the constructive criticisms that were pointed out to her. Otten also is apologetic towards any harness or unkindness directed toward some of the writers in her discussion and says that it was unintentional. She then thanks a couple of the writers (Barnicot and Mourant), for pointing out a paper of McDonald and Zuckerman that discusses the effectiveness in the production of antibodies against A2 influenza virus in persons with type O, A, or B blood. She seems to meet the constructive criticisms of her paper by going on to discuss aspects or suggestions that some of the commentators have mentioned.
This article discusses the distribution of the ABO blood group, the theories of geographic distribution, and how they correlate with diet and immunity to certain infectious diseases. The author states her disagreement with these theories is due to inconsistencies in the research methods and results and therefore provides little evidence to prove infectious diseases favour certain immunilogical characteristics. This leads the article into a discussion of organisms and their immunilogical capabilities in the production of antibodies against viruses or bacteria that carry antigenic characteristics similar to those of their own blood group.
Research results to support this theory are provided. The research analyzed the bacillus of the bubonic plague in Europe in particular, the areas most intensely affected by the outbreak. The findings provide evidence that the areas hardest hit by the plague have diminishing O frequencies that are unable to defend against the H-specific antigens of the plague. Smallpox is another example used; the theories discussed associate high A-antigen frequencies with the spread of the A-reactive smallpox virus. Other theories discussed in this article include evaluating the relation of diet and ABO frequencies. These theories attempt to find a correlation between high A frequencies and higher fat intake and between high B frequencies and high carbohydrate intake. The inconsistencies in this theory are made apparent when O frequencies are not found to correlate with anything in specific.
One explanation for the results found in this study can be attributed to the lack of information on the effects of having a diet high in carbohydrates and starchy staples. A second explanation provided for these results can be that the occurrence of diets high in carbohydrates and starchy diets has only happened recently, perhaps too recently to see the effects on the gene frequencies and therefore, too recently to prove or disprove this theory.