What Longevity Doesn’t Understand About Medicine
I am seeing more and more patients immersed in the world of longevity coming into my cardiology clinic.
If doctors don’t understand and adapt to this world, we are going to be increasingly out of step with the information ecosystem that our patients are living in and the preferences that they have about what the medical system is supposed to be for.1
I looked at the recent news cycle about Bryan Johnson’s autoimmune disease as an interesting insight into the collision between longevity and traditional medicine.
The last time I wrote about Bryan Johnson, I called him the living embodiment of Goodhart’s law:
Bryan Johnson is the living embodiment of Goodhart's law
Bryan Johnson is an entrepreneur who is trying to use technology to avoid dying.
I’m writing about him again today because of the recent news that he’s been diagnosed with a condition called autoimmune gastritis, where his body’s immune system attacks the lining of his stomach and causes problems with absorbing some nutrients.
His essay announcing the condition contains a critique of mainstream medicine as being behind the curve, missing the links that made this diagnosis, and being too timid to actually treat the underlying cause:
He and his team are planning to fix the gaps that medicine hasn’t been able to solve.
I would recommend reading the whole piece as a window into his thinking.
I would also recommend reading it because it reveals how little he - like too many people in the world of longevity - actually knows about how medicine works.
Before I get into any other details of this piece, I wish Johnson well and hope that he does not have progression of disease or a side effect from treatment. And so what follows are my thoughts about what he writes in the piece, not ill will for the man himself.
Thoughtful clinical reasoning made his diagnosis
The ordinary medicine Johnson dismisses is what actually caught the disease.
The diagnosis didn’t come from artificial intelligence or a proprietary algorithm, it came from established methods and a few minutes of clinical reasoning.
Look at how he describes his case - he is an otherwise healthy man with a history of hypothyroidism.
The first step - low iron levels
On routine bloodwork, his ferritin was found to be persistently low. Low ferritin is often an indication that overall iron stores are low.
He describes that no one could figure this out and that he was dismissed because he didn’t have anemia.
Low ferritin without anemia is something that 10 years ago would have been dismissed by medicine. But contemporary medicine recognizes non-anemia iron deficiency as an important entity to be evaluated. Look at this from 2012 or this from 2016.
Thinking about iron deficiency gives you a few different possibilities:
A nutritional deficiency - not taking in enough iron
A problem with absorbing iron leading to a functional nutrient deficiency
A slow loss of blood that wasn’t obvious enough to be seen macroscopically
Johnson’s team first started out with supplementing iron, thinking that because of his plant based diet, solving the problem might just be as simple as a dietary change.
It’s pretty odd for men to have iron deficiency without blood loss or a nutrient problem, because men don’t menstruate and so aren’t losing blood regularly. Iron deficiency is much more common in women, which is why women’s multivitamins contain iron and men’s multivitamins don’t.
Oddly, Johnson also discussed IV iron treatments as though they are a cutting edge method of fixing iron deficiency. In reality, fixing iron deficiency with oral iron formulations takes about a year and also makes people constipated, so most doctors have gone away from oral iron supplements and moved towards IV iron as the standard of care.2
The second step - look for blood loss
When that didn’t work, they thought about looking for blood loss, which led them to a colonoscopy to check for tumors or polyps.
The colonoscopy didn’t show any explanation.
As an aside, it’s surprising to me that he hasn’t been getting regular colonoscopies if his project is about not dying.
After all, colon cancer is detectable and preventable with colonoscopies, and it’s increasingly being seen in younger people.
The screening guidelines - which you might quibble with - would have already recommended he get a colonoscopy.
The next step - endoscopy with biopsy
But an upper endoscopy with a biopsy did make the diagnosis.
Johnson describes this as a triumph for his team - “My team had exercised great foresight though, anticipating this possible outcome. In addition to a colonoscopy, they’d ordered an upper endoscopy to be performed at the same time. The combined procedure is a bi-directional endoscopy. Probes would look at my entire intestinal tract, up from below and down the throat.”3
He describes that the biopsies taken showed the ultimate diagnosis. He also reports blood tests taken looking at the antibodies attacking the stomach also came back positive, confirming the diagnosis of autoimmune gastritis.
But doing an upper and lower endoscopy as part of a thorough anemia workup isn’t groundbreaking medicine, it’s just medicine.
And a smart doctor who thought about the case for a few minutes would have hit on the unifying diagnosis earlier.
Putting the pieces together
The final diagnosis makes sense based on nothing but the history.
He’s a 48 year old man with a history of hypothyroidism (an autoimmune disease). He had iron deficiency that wasn’t responding to supplements.
If you were to tell a second or third year internal medicine resident that you had a man with non anemic iron deficiency, they would immediately look for a source of bleeding and think about an absorption problem.
If you add in the fact that he has one autoimmune disease, you very quickly get to a malabsorption problem as the most likely unifying explanation.
When I first started reading the case, I thought about celiac disease, but autoimmune gastritis would be on the list of possible diagnoses from any doctor who was thinking critically about the situation.
Putting the pieces together to come up with a unifying explanation is a well described technique in medical reasoning - doctor’s often reference Occam’s Razor as a foundational mental model for how we think about patient cases.4
Why does it matter how Bryan Johnson thinks about the process of making a medical diagnosis?
Johnson talks about the diagnostic process the way a smart, non-medical person talks about the diagnostic process.
The best analogy I can give about this is that it’s the difference between someone who is conversational in language and someone who is fluent in a language speaks - he clearly has a lot of information, but it’s put together in a way that makes it clear to a native speaker that he doesn’t really understand what’s going on.
This is both illuminating and important, because he very quickly segues into treatment.
If someone doesn’t understand the diagnostic process all that well, how can you expect them to understand the decision-making around the risks and benefits of treatment?
For a condition that is causing him no symptoms - and for which his iron deficiency was easily corrected with a common medical intervention, IV iron - Johnson quickly proposes some pretty aggressive interventions.
He suggests monitoring the disease with bloodwork and, if it looks like there is progression, will consider treatments that are totally speculative and based on a very detailed, but superficial understanding of what is happening with his biology: immune system modulation, treatments being studied for different tumors, experimental immune-cell therapies adapted from yet a different type of cancer treatment.
The proposed treatment pathway replicates a common mistake in medicine: confusing the understanding of biochemical pathways with an understanding of the entirety of the biology.
We’ve made this type of mistake in medicine many times over
The longevity movement is speedrunning the history of medicine, and because it doesn’t understand medicine and doesn’t know the history, it’s going to make all of the same mistakes that medicine has made before.
Trying a treatment based on biologic plausibility is a mistake that people have made over and over again in medicine, sometimes to catastrophic effect.
Look at the CAST trial, probably the most instructive failure in the history of medicine - cardiologists used to think that suppressing irregular heartbeats after a heart attack was a good thing, because people who had more irregular heartbeats also had a higher risk of death.
But it turned out that suppressing irregular heartbeats made people’s EKGs look better but also increased their risk of death.
This style of mistake - falling in love with the biology and expecting it to work out - has been made over and over again in medicine.5
Even experts in traditional medicine are still making that mistake.
But if you don’t understand the history of how elegant mechanisms and biologic plausibility don’t necessary mean a beneficial treatment, you are just as likely to be wrong with your intervention as you are to be right.
That is the permanent lesson: a plausible story about the body is a hypothesis, not a result, and biology routinely humiliates plausible ones. The particulars change – antioxidant supplements that were supposed to prevent cancer and instead caused more of it; vitamin D supplements raise blood levels of vitamin D but don’t prevent disease – but the lesson never does.
And too often the commercial longevity industry is built almost entirely on plausible stories, and thinks medicine is failing because we are too cautious to act.
The reason we are cautious isn’t that we’re too scared to treat people with things that make sense. It’s that we have the scar tissue of memory from the places where things that were supposed to work actually killed people instead.
To relearn those lessons from scratch isn’t disruption. It’s making a new generation of paying customers repay tuition medicine already covered in full.
Bryan Johnson is right that the absence of symptoms is not the presence of health. But he should sit with the important sequel: the presence of a mechanism is not evidence of a cure.
Read this piece from Adam Cifu, MD on the way that he is watching medicine change as more and more longevity-adjacent ideas are infiltrating culture and the expectations that patients have of the medical system:
As any internal medicine intern how many times they’ve prescribed IV iron and you’ll quickly realize that this is an incredibly common thing to use in contemporary medicine.
It’s not true to suggest the probes looked at his entire GI tract. After all, the endoscopies miss the small bowel. A video capsule endoscopy is often done when an upper and lower endoscopy don’t demonstrate a source of bleeding.
Although any time to reference Occam’s Razor, a snarky doctor is obligated to mention Hickam’s Dictum - “a patient can have as many diseases as they damn well please” - as a rejoinder.
Look at this paper from 2018 written by Paul Ridker (a giant in cardiovascular prevention) about personalized therapy for heart disease. Ridker cites two trials that were ongoing at the time - STRENGTH and PROMINENT - as examples of data in support of treating cardiac risk related to triglycerides. There’s just one problem - when those trials were finally published, they were both neutral. And so this error isn’t one that longevity people are making alone. It’s a sin that people in medicine commit all the time.
Eleven years of a low ferritin despite supplementation before his team did an endoscopic work up. Sounds like he needs a new team, which is further supported by the proposed unproven potential treatments.
What longevity doesn’t understand about life – that’s what the title should be.