A number of years ago, I came across a book called Eat Right For Your Blood Type, which argues one’s blood type determines the foods that are optimal for them, and also affects one’s personality. It’s one of those claims I thought was total bullshit until I began reading through the section for my blood type, which happens to be “B.” The generalizations there were spot on — but hey, horoscopes, or anything that vaguely assigns characteristics to big groups of people, can be spot on too, right? And I’ll never stop eating corn or lentils. One of the disconcerting parts of the write-up is the assertion that type B people tend to lose their mental acuity and memory fairly drastically with age. I’ve thought about this from time to time when I can’t seem to find the word I want or can’t remember events that at one point seemed unforgettable, but have generally dismissed it — until now. A new study published in Neurology asserts that, indeed, blood type may correspond to loss of memory later in life, particularly for people with AB type blood.
The link between blood type and various health conditions has been studied for some time, and scientists believe there is a connection between blood type and heart disease and stroke, which, aside from being dangerous in themselves, also increase one’s risk for memory loss or dementia.
Researchers at the University of Vermont’s College of Medicine wanted to focus on the specific connection between blood type and cognitive impairment. The team examined data from over 30,000 subjects in the U.S., 495 of whom developed cognitive impairment during the 3.5-year course of the study. They compared those subjects with 587 subjects who demonstrated no impairment. They found that 6% of the cognitively impaired subjects had type AB blood, which is the rarest and newest type. When they adjusted the data for differences in age, gender, race, and location, they found that people with type AB blood are roughly 82% more likely to experience some symptoms of cognitive impairment as they age. The study did not specifically examine dementia risks, though there’s an overlap between many of the symptoms noted and dementia.
Researchers also found that people with type AB blood have a higher level of the factor VIII blood clotting protein, which, in addition to being associated with a higher risk of strokes and heart attacks, also contributes to an increased risk of memory, attention, and other cognitive problems. Because of the established connection between blood type and vascular problems such as strokes, it makes sense that there seems to be a connection between blood type and cognitive impairment, but as of now, the connection is correlative, not causal — researchers can’t provide that the AB type blood is the actual cause of the impairment, so further studies will undoubtedly follow.