8/15/2026
I'm going to continue yesterday's sharing from Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.
Topol coins two interesting terms in the book. He calls the small group of exceptionally healthy older people the “Wellderly”—healthy-aging outliers—and contrasts them with the much larger group he calls the “Illderly,” people whose later years are increasingly affected by chronic disease.
Here are some numbers that put the situation into perspective:
In the United States, 60% of adults aged 18 and older have at least one chronic disease.
40% have two or more chronic diseases.
Among people aged 65 and older, 80% have two or more chronic diseases, 23% have three or more, and about 7% have five or more.
As Topol puts it:
“If you or someone you know has a chronic condition, it is probably one of the big four: diabetes, heart disease, cancer, or some kind of neurodegeneration. Beyond these, chronic lung and kidney disease are high on the list.”
This, he says, is what his book is ultimately about: how we can maximize our healthspan and stay on the Wellderly path rather than moving toward the Illderly path.
Why the immune system?
When Topol turns to age-related diseases, I was somewhat surprised that he began with the immune system.
But his explanation is fascinating.
He writes:
“The recognition of the immune system as a common mechanistic underpinning for chronic diseases, whether it be related to why they occur or to the untoward sequelae that they induce, is a historic turning point.”
In other words, the immune system plays a central role in many of the diseases associated with aging.
Heart disease, cancer, and neurodegenerative diseases often take decades to develop. That means there may be a very long window during which we can potentially intervene before they become clinically apparent.
Take atherosclerosis, which can eventually lead to heart attacks and strokes. It remains the world's leading cause of death and disability. A major component of the process is inflammation in the walls of blood vessels—and inflammation is generated by the immune system.
Cancer provides another example. Cancer doesn't usually become deadly simply because a tumor exists; the danger often comes when cancer cells spread to other parts of the body. Our immune system plays an important role in recognizing and controlling abnormal cells.
The Brain is another example. Increasing evidence points to the role of chronic inflammation and immune-system activity in neurodegenerative diseases such as Alzheimer's and Parkinson's disease.
And when the immune system mistakenly attacks our own tissues, we get autoimmune diseases—for example, attacking the nervous system in multiple sclerosis or the joints in rheumatoid arthritis.
Topol therefore makes a much broader argument:
Dysfunction of the immune response is one of the principal drivers of accelerated aging.
This is where things get particularly interesting.
The answer isn't simply to “boost” the immune system. An immune system that is too weak can leave us vulnerable to infection and disease, but an immune system that is excessively or chronically activated can also damage our own tissues.
Topol compares it to a Goldilocks problem:
Too little isn't good. Too much is bad. We need to get it just right.
And perhaps the most important part is that the right balance may be different for different people and different tissues.
Only relatively recently have scientists begun developing tools to precisely modulate immune and inflammatory responses. According to Topol, this is an area where the science is advancing rapidly.
Which brings me to the question I'm most interested in:
If healthy aging depends partly on keeping our immune response “just right,” how do we actually do that?
That may be where the story gets really interesting.
