A recent narrative review2 published in the American Journal of Clinical Nutrition explores how the relationship between fructose and humans’ ancient foraging instincts might be to blame for the onset of Alzheimer’s disease (AD).
Lead author Richard Johnson, M.D., theorizes that because humans evolved to sometimes be quick-thinking risk-takers in the pursuit of food, fructose may actually enhance that instinct by getting in the way of our memory centers and attention to how much time has passed.
In other words, a human with less regard for time and recent memory may be more likely to forage for food more quickly and effectively, tending to ignore risk or other distracting factors.
But as with anything, too much of a good thing can lead to unintended problems.
“We hypothesized that the fructose-dependent reduction in cerebral metabolism in these regions was initially reversible and meant to be beneficial,” Johnson wrote. “However, the chronic and persistent decrease in cerebral metabolism driven by recurrent fructose metabolism leads to progressive brain atrophy and neuron loss with all of the features of AD.”
So, this once-lifesaving brain function may be firing too often in the modern brain and leading to permanent damage, leading to diagnoses like AD.
Scientists noted that wandering off—a common symptom of AD—may even be linked to the foraging instinct promoted in early humans.