Lower Blood Sugar and Memory
There is an interesting study published in the October 23, Issue of Neurology, a peer reviewed magazine pertaining to blood glucose and memory. The researcher published an article titled “High Glucose Linked to Poorer Memory, Even in People Without Diabetes”. In essence the researcher took 144 subjects with blood glucose in what is considered the normal range (80 -120) and conducted a memory test. What the researcher found was that people with higher ‘normal’ blood sugars had less ability to memorize and recite a list of numbers, than people with lower normal Blood Sugar. No cause and effect was determined. So, while the data was associative, it was not determined to be causal. Because of the timing of the study, I was not able to obtain a copy rom my sources or a proper citation. I read about the findings in USA Today. But the reference indexes will require another two months to catch up.
Anyway, that is all academic gibberish to the average person. But the speculations about the implications of the article are enormous. First, what if people who suffer from Alzheimer’s are changed from a normal institution diet to a low carb diet, might that improve their cognition? Are diabetics who maintain higher blood sugars at risk for diminished mental acuity? Is this another of the long term effects of diabetes, ranking with kidney failure, neuropathy, blindness, heart disease etc.? If so at what point is damage done? I need to point out that this is a small study, and again it does not establish a causal relationship. In other words other factors that may be at work limit cognition, and it could turn out that diabetes is of no major impact.
This might be thought of as an outlier study, except it is not. In 2008 a paper was published that came to similar conclusions. The paper “Functional brain connectivity and neurocognitive functioning in patients with long-standing type 1 diabetes with and without microvascular complications: a magnetoencephalography study” found that people who have had diabetes had some cognitive differences in cognition. Specifically the study found that “compared with sex- and education-matched type 1 diabetes patients and control subjects, type 1 diabetes had decreased functional connectivity. This decrease was most profound in the left and right central and parietal areas” (van Duinkerken et al., 2009, Page 2340). Again this is not a definitive study but it does form part of the rationale for concluding that higher blood sugars might decrease cognition. In this case the researcher argues that restricted blood flow because of clogging of small vessels might be the cause. Again the entire thing is full of supposition.
In the second instance only 26 diabetics were used, to make their conclusions. Yet in this case, the researcher did attempt to establish causation. However with so few test subjects the real nature of the association may be limited.
Now I can assure you that no one goes into doing one of these studies to show association. There is an old saying academia that the rigorous show causation and the also runs show association. So if these studies could have been used to show causation both would have. I know when I did my dissertation I wanted to show causation, I did not even get association. LOL I came away with no association and certainly no causation, so these two really did pretty good.
So should low carb be part of every institutional diet in order to boost mental acuity? I imagine it would not hurt, except of course one would not want to send a diabetic into a low. How serious is the high blood sugar and mental impairment? It really is unproven science. Yes there might be an issue, or there might not be. I do not think anyone should change diet based on these studies. Someday maybe we will, today no.
van Duinkerken, E., Klein, M., Schoonenboom, N. S., Hoogma, R. P., Moll, A. C., Snoek, F. J., Diamant, M. (2009).
Functional brain connectivity and neurocognitive functioning in patients with long-standing type 1 diabetes with and without microvascular complications: a magnetoencephalography study. Diabetes, 58(10), 2335-2343. doi: 10.2337/db09-0425