That Oct 21 study you link is interesting - or at least the abstract as it's paywalled. To quote from the abstract:

>> The authors found that glucose uptake is greater in microglia compared to astrocytes and neurons...

As I understand it, astrocytes are the major glucose consumer in the CNS. They then use glucose to produce glutamate that's directly consumed by neurons.

Astrocytes have the same kind of glucose transporters (GLUT1) as striated (AKA skeletal) muscles, where the "insulin resistance" cascade starts (at least in one theory of insulin resistance - I won't get into the competing ones here).

One model of Alzheimer's (T3D) posits that, as the brain becomes insulin resistant, neurons starve and die - and both tangles and plaques follow from that. Another model (inflammation) posits that the damage comes from the immune system defending (or over-defending) the CNS, resulting in cytokine damage. Both models agree that what we call Alzheimer's is the end stage of a very long process.

The linked study seems to support T3D — once GLUT1 in astrocytes is impaired, CNS cells are dependent on cell wall diffusion of glucose (which is independent of insulin levels) - or ketone bodies.

I go back and forth, depending on which study I've been reading most recently, but there's no reason it can't be both mechanisms in some combination.

TL;DR: yes, reduce sugar, particularly fructose. If it doesn't cause Alzheimer's, there are loads of other reasons to do so.