Despite the efforts made in recent years in terms of research, the Alzheimer’s continues to be an incurable disease.. In order to find treatments and therapies that can be used to reverse the disease, or at least to slow or stop its progression, it is essential to understand the factors behind it.
Thus, a group of scientists has identified a new element that could play an important role in the course of this form of dementia: a common type of sugar found in many foods called fructose.
A survival mechanism
As these authors explain in the specialized media American Journal of Clinical Nutrition, the theory is supported by a certain amount of previous evidence indicating that, in origin, fructose in the brain causes a series of changes that helped our ancestors in their search for food. However, it seems that, in the modern world, these same changes could be directly linked to the development of Alzheimer’s.
Specifically, fructose is a sugar that is found naturally in foods such as fruits or honey, but that our own body also produces when we eat very fatty, sugary, or salty foods. When this happens, endogenous fructose could inhibit certain parts of the brain’s metabolism. In this way, it would block out distractions, such as recent memories or the attention to the passage of time.
The point is that this inactivation could now be permanently on due to changes in our diet and lifestyle that have led us to seek a higher proportion of foods high in fat, sugar, and salt (which stimulates a greater production of fructose by the body itself).
joining dots
This work, then, what it does is join the points drawn by different previous studies that had described the details of this adaptive mechanism of fructose and those that have related the fructose levels in the brain with Alzheimer’s.
Based on this, the researchers hypothesize that the effects of fructose and its by-product, intracellular uric acid, are responsible for the characteristic accumulations of proteins that appear in Alzheimer’s.
These effects, among others, include reduced blood flow to the cortex brain, hippocampus and thalamus, and increased blood flow in the visual cortex (which, by the way, is linked to food reward signals). Even so, the relationship is not so clear, since there are other relationships to take into account: for example, many factors of the increase in the production of fructose in the brain are in turn known risk factors for Alzheimer’s.
References
Richard J. Johnson, Dean R. Tolan, Dale Bredesen, Maria Nagel, Laura G. Sanchez-Lozada, Mehdi Fini, Scott Burtis, Michael A. Lanaspa, David Perlmutter. Could Alzheimer’s disease be a maladaptation of an evolutionary survival pathway mediated by intracerebral fructose and uric acid metabolism? American Journal of Clinical Nutrition (2023). DOI: https://doi.org/10.1016/j.ajcnut.2023.01.002