Posted 07 March 2006 - 08:01 AM
The reason we never get people's "blood type" in the 21st century is that it is no longer useful. If/when someone needs a blood transfusion in this day and age we do high tech instant matches that involve a zillion more antigens than the ABO system was able to detect. During the cold war or World War 2 that was all we knew, so at least the odds of having completely fatal transfusion was somewhat lower. If you told a hospital that you were "type A" or whatever, they would respond by saying "that's nice", ignore you and re-type your blood with our modern antigen detecting systems.
Here's an interesting review re: blood types:
The concept of blood type originated in the early years of this century with German pathologist Karl Landsteiner. He identified two proteins, or antigens, that he found on the surface of the red blood cell. Calling these antigens A and B, Landsteiner proceeded to describe four blood groupings, A, B, AB, and O, according to whether they had one or the other, or both, or neither. Since then we've learned that type A's can have either AA genes or AO genes, B's can be BB or BO, ABs have to be AB, and O's have to be OO. The genes for these proteins are passed to us from our parents. Landsteiner didn't know it at the time, but the ABO identification system was only the start. In the years since his pioneering work, 276 discrete red-cell antigens have been discovered.
Let's examine D'Adamo's logic by looking at hypothetical pairings of four couple's: a type AB couple, a type A couple, a type B couple and a type O couple. According to D'Adamo, each of these couples would be a descendent of a separate ancestral populations. If we then looked at the children from these pairings, those from the AB couple could end up from the A, B or AB ancestral populations, the type A couple could produce children from the A or the O ancestral population, and the type B couple could have children that were from the B or the O ancestral population. Only the type O couple would pass the same blood type on to all of their children.
Since there are 50,000 to 100,000 genes contained in human DNA, the passing of genes from one generation to the next is tantamount to a role of the genetic dice. Granted what's on those dice is determined by one's parents -- and there are some factors that do seem to dominate -- the potential for variability is enormous. There is no question that over the millennia there has been an infinite variety of genetic mixing. Scientists at the Human Genome Project have been analyzing the structure of human DNA, a project expected to span 15 years and cost several billion dollars. It makes it all a bit of a stretch to say, for example, that a type O today has the same genetic imperatives as a type O roaming the Savannah with spear in hand.
Blood type is not totally benign. For many years, scientists wondered why type O's were more likely to than other blood types to develop stomach ulcers or stomach cancer. In 1993, scientists found that ulcers were caused by helicobacter pylori, a bacterium which had a special affinity for one of the unique type O proteins. A geneticist at Oxford University who checked for other significant associations between the ABO blood types and the incidence of disease, reported that there were only seven,; the relationships were often weak; and most, like ulcers, originated somewhere along the digestive tract. If the ABO blood type was that much of a key, as D'Adamo posits, these relationships would strong and plentiful.
It may well turn out that there are important interactions with between certain foods and one's blood type. D'Adamo, unfortunately, offers little in the way of scientific evidence, relying instead on a collection of anecdotal reports and case histories. His speculation that the one gene responsible the ABO blood type could exert such a dominant influence over everything else is unable to stand on its own merits. In the end, D'Adamo adds the caveat that individual variations still occur within blood types, so you shouldn't expect all of his recommendations to apply to you. It's nice to have it both ways, especially where book sales are involved.
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I only post these items when I feel that there is important misinformation. ULtimately thanks to living in a wonderful, open and free society one is free to eat and think whatever one wants to.
maineman
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