An ancient human instinct to search for food, fueled by the production of fructose in the brain, may hold valuable clues to the onset of Alzheimer’s disease. At least that’s what researchers from the University of Colorado Anschutz Medical Campus (United States) say in a study recently published online and published in The American Journal of Clinical Nutrition (Source 1).
Clearly, Alzheimer’s disease would be a detrimental consequence of an evolutionary survival pathwayused by our distant ancestors in times of food shortage.
Fructose to stimulate foraging
When they were about to starve to death, early humans had a survival reaction which encouraged them to search for food, explain the researchers in a press release (Source 2). But this requires concentration, impulsiveness, determinism or even risk-taking. As many parameters as the metabolism of fructose would have made it possible to set up, by inhibiting other factors, such as memories or the notion of time.
Whether consumed through food or produced in the body, fructose would thus have been essential for human survival. This sugar would reduce blood flow to the cerebral cortex involved in self-control, as well as to the hippocampus and thalamus. What allow a greater blood flow around the visual cortex, associated with the food reward.
« We believe that initially the fructose-dependent reduction of brain metabolism in these regions was reversible and believed to be beneficial said Dr. Richard Johnson, first author of the study. “ But a chronic and persistent reduction in brain metabolism driven by recurrent fructose metabolism leads to progressive cerebral atrophy and loss of neurons with all the hallmarks of Alzheimer’s disease “, laments the researcher.
An evolutionary remnant stuck on “on”
Because if this evolutionary mechanism has undoubtedly allowed us to survive periods of scarcity, it would have been maintained on “ on », a bit like a switch. This would explain our certain interest in fatty, salty and sweet foods, all of which lead an overproduction of fructose. Ultimately, this could lead to brain inflammation and, in fineAlzheimer-type dementia.
« One study found that if you keep lab rats on fructose long enough, they get [une accumulation de] tau and beta-amyloid proteins in the brain, the same proteins seen in Alzheimer’s disease”, said Dr. Johnson, noting that there are memory lapses and problems of orientation in space in animals fed with fructose. “ You can also find high levels of fructose in the brains of people with Alzheimer’s disease », he added.
In view of these results, the research team suggests that “ dietary and pharmacological trials aimed at reducing fructose exposure or blocking [son] metabolism to determine if it might be beneficial in the prevention, management or treatment of Alzheimer’s disease.