This study, and related article in easy-to-read layman's terms, point to the importance of diet to reduce the likelihood of Alzheimer's disease:

study - https://www.frontiersin.org/articles/10.3389/fneur.2022.900048/full
article - https://www.theepochtimes.com/regular-consumption-of-this-helps-keep-alzheimers-at-bay_4711696.html

The article may be behind a paywall (if you know someone with a subscription, "friends read free").

Brief excerpts:
Originally Posted by article
Alzheimer's patients' gut microbiomes differ tremendously from that of a healthy gut

Lipopolysaccharide Is a Major Culprit of Alzheimer’s Disease

The toxin is a variation of lipopolysaccharides (LPS)—BF-LPS. It is a neurotoxin secreted by the Bacteroides fragilis in the intestines and leaks from ruptured bowels, to enter the blood circulation system. It is capable of breaking through the blood-brain barrier (BBB) and entering the brain.

Nuts Offset LPS Toxicity

Bacteroides Love Saturated Fats
The recommended dietary changes include:
- reducing the intake of foods wth a high concentration of saturated fats,
- increasing the intake of fiber including nuts such as almonds, hazelnuts, walnuts, macadamias, and pistachios.

The article's explanations, graphics, and links to studies make it well worth reading and sharing.