Alzheimer’s May Start Decades Before Diagnosis

In 1985, a Swiss pathologist noted Alzheimer’s disease-like changes—plaques and tangles—in the brains of about three-quarters of a small group of men and women in their 50s and 60s who had died from other causes. Most brains from people under age 30, however, did not have these features. But these studies just involved a few dozen people.

As I discuss in my video, based on thousands of autopsies, we have seen what appear to be the first silent stages of Alzheimer’s starting as early as our 20s in about 10 percent of the population and increasing to about 50 percent by age 50. “Just as the first malignant cells in cancer…fail to produce any clinically detectable symptoms but represent a larger and potentially life-threatening disease process, the presence of… [these tangles in the brain] may constitute a true threat.”

The high prevalence of the first stage of the disease and its extraordinarily long duration—most people don’t get diagnosed until their 70s—had not been fully appreciated until now. We now understand that neurodegenerative brain changes begin by middle age, and so does cognitive decline; we start losing brain function in our 40s.

Before people are diagnosed with Alzheimer’s, they are diagnosed with mild cognitive impairment, or MCI. That’s when cognitive decline becomes clinically apparent. A few years later, Alzheimer’s may be diagnosed, which then eventually results in death. We never knew what was happening before mild cognitive impairment was diagnosed—until now. There appears to be a slow decline in brain function and the buildup of plaques and tangles in the brain for decades before Alzheimer’s is diagnosed.

This finding potentially has profound implications for the prevention of dementia: We have to start early before marked brain loss has occurred. The good news is that brain disease is not inevitable, even after age 100. The oldest woman in the world, aged 115, retained the brainpower of those practically half her age. Had she had not died from stomach cancer, she could have kept on thriving.

It turns out, there’s no such thing as dying of old age. In 42,000 consecutive autopsies, centenarians—those living past 100—succumbed to diseases in 100 percent of the cases examined, though most were perceived to have been healthy just prior to death, even by their physicians. In actuality, not one died of “old age.” Until recently, advanced age has been considered to be a disease itself, but people don’t die as a consequence of old age as commonly assumed, but from diseases and, most commonly, heart attacks.

One of the most intriguing findings from the 115-year-old woman mentioned above was that her body showed no significant atherosclerosis and the arteries in her brain were clear as well. That may have been one of the secrets to her mental clarity. There is emerging consensus that “what is good for our hearts is also good for our heads,”

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations—2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not to Die: The Role of Diet in Preventing, Arresting, and Reversing our Top 15 Killers.


Peanut Butter Smell Test for Alzheimer’s 
Reducing Glycotoxin Intake to Prevent Alzheimers
Preventing Alzheimer’s Disease with Diet


Jim Ven
Jim Ven2 years ago

thanks for sharing.

Siyus C
Siyus C2 years ago

Thank you for sharing.

heather g
heather g2 years ago

That's why nutrition and physical activity is of utmost importance....

Tania N
Tania N2 years ago

Thanks for the info.

Winn A
Winn Adams2 years ago


Ruth S
Ruth S2 years ago


LF F2 years ago

I think alot of diseases are this way. We need to pay attention to our health on a regular basis and encourage it to heal w our supplements, healing foods, and extra sleep when our bodies are telling us that we need it.

ERIKA S2 years ago

thank you for sharing

Twila H
Twila H2 years ago

Horrid evil disease. My maternal grandmother had it. Now my mom is in the mid stages of it herself, so I know that means I will have a good chance of getting this myself. Hope and pray for a cure! TYFS!

Debbi -
Debbi -2 years ago

That isn't surprising. Many cancers are silent, few if any symptoms until stage 4, when it's too late to save you. The problem is discerning the very subtle signs of serious health issues. I remember hearing about a group of scientists working on blood tests that would detect many different and deadly health problems. Evidently they haven't been successful.