I have been following research that bears on AD (Alzheimer's Disease), because my mother basically died of AD, and it definitely runs in families. I have a personal incentive, one might say. I have always been a smart guy with a great, nearly "eidetic" memory. Now, at age 72, I find my memory is starting to malfunction, and I worry that this may be a sign of AD rearing its ugly head.
There are two apparent "culprits" in AD.
SO Culprit 1:
There is a brain protein called amyloid protein. It is constructed and then destructed as part of normal brain functioning. However, for reasons that nobody knows, in some people this process fails progressively as the person ages. When amyloid protein is NOT destroyed effectively and completely, a substance called beta amyloid remains. AND as everyone who has done even casual reading about Alzheimer's is aware, beta amyloid "plaques" in the brain are the principle means of recognizing that AD has occurred. I say "has occurred" because basically excess beta amyloid in the brain is not detectable until after death, and specific autopsy actions are taken postmortem to see the beta amyloid plaques and tangles. After death is the very essence of "too late", of course. Beta amyloid is toxic to brain neurons and other brain structures and cells.
Culprit 2:
There is a substance call tau protein that all cells use to build microtubules, which are critically necessary structures in all cells. However excess tau protein production kills nerve cells. Of course, nerve cells are what the brain is comprised of. Excessive tau protein production causes one's brain to deteriorate, progressively. This is the second candidate culprit, "causing" Alzheimer's Disease, though of course no one knows what causes excessive tau protein production, nor in fact, just how much tau protein production is "excessive".
Right now, all the "action" in AD research seems to be research in how to prevent beta amyloid buildup into plaques and tangles that basically destroys people's brains. There is certain (anecdotal) evidence that amphetamines, which are for example known to increase one's IQ by significant amounts, also work to enhance and increase brain function in direct, physical ways. FOR EXAMPLE: some persons whose cochlear implants were not effective (because prior long-term profound deafness caused the brain to ignore and not process the new auditory input from the implants) have been "cured" of this difficulty permanently by administration of a short course of amphetamines. An amphetamine regimen could help (probably does help) one's brain deal with beta amyloid buildup.
OTOH, amphetamines are not good for you as a permanent regimen-- the hippie slogan "Speed Kills" is well-known and quite accurate. So what to do? Well shucks, there are well-known foods and food supplements that when taken, enhance the body's own production of d-amphetamine. Specifically:
Citicoline. Citicoline is a naturally occurring brain chemical and a U.S. Food and Drug Administration-approved dietary supplement. ...
Methionine. Methionine is an essential sulfur-containing amino acid needed to make protein...
Mineral Supplements... (covered by any good, complete daily multivitamin pill)
Vitamin B-6. (also covered)
So. It looks like I should (perhaps ?) consider adding citicoline and methionine to my already heavy round of daily supplements. Please recall that, up until 1928, pernicious anemia was a deadly disease, that turned out to be completely curable by eating calves' liver, which provided nothing more than good protein, iron, and vitamin B12. It is entirely plausible that citicoline and methionine supplementation could ameliorate (or even "cure") Alzheimer's Disease. Also please recall that this is not proven, nor even studied in a systematic, scientific way.
OTOH, these substances are food, naturally occurring and with no known, bad side effects. If your body does not need or use these things, then they pass through, giving one's urine a richer, yellower color than is usual. Americans who commonly take a multivitamin as a "just in case" measure, are said to have the most expensive urine in the world. Taking food supplements that could improve brain function and just might act as a palliative to beta amyloid buildup; supplements which seem likely enough to be helpful, so that studies are being designed to evaluate them as we speak, could be regarded as cheap, "it-just-might-help" insurance against the depredations of a scary, deadly disease, i.e. AD.
I for one am not going to turn up my nose at this tiny, not-scientifically-established possibility.
UPDATED much later (12-APR-2024): Another (extensively studied and "almost proven") factor known to affect brain health is simple and quite easy to manage: Get more sleep. An adequate amount of nightly sleep is now known to help your brain health. It improves memory and learning retention and emotional resiliency and other brain functions that people consider important. The widely adopted attitudes reflected in sayings such as "I will rest when I am dead" and "Sleep is like a drug. The more you get the more you need" are in fact now "known" to injure your brain and gradually make you more stupid. Unless you like and desire becoming gradually less intelligent, get more sleep.