Bryan Johnson Was Diagnosed with Autoimmune Gastritis
Doing everything “right” doesn’t make you immune to disease.
Many people know Bryan Johnson from the Blueprint project and the documentary Don’t Die. At 48, he spends around $1 million a year optimizing his health. His blood tests, fitness, sleep, and nutrition are among the best documented in the world.
Yet he was recently diagnosed with Autoimmune Gastritis.
The surprising part
He had almost no symptoms.
For more than 10 years, the only consistent abnormality was low ferritin (low iron stores). His hemoglobin and most other tests remained normal.
Instead of ignoring it, he kept searching for the cause.
How was it discovered?
Before a routine endoscopy and colonoscopy, one blood test came back positive:
Parietal Cell Antibody: about 5 times above normal
The endoscopy looked almost normal. There were:
* No ulcers
* No bleeding
* No stomach cancer
* No Helicobacter pylori infection
However, stomach biopsies showed mild chronic inactive gastritis, confirming Autoimmune Gastritis.
What is Autoimmune Gastritis?
It is an autoimmune disease in which the immune system attacks parietal cells in the stomach.
These cells normally produce:
Stomach acid (needed for digestion and iron absorption)
Intrinsic factor (essential for vitamin B12 absorption)
As these cells are lost, patients may develop:
* Low ferritin (often the earliest sign)
* Iron deficiency anemia
* Vitamin B12 deficiency
* Numbness or tingling
* Memory and nerve problems
* Reduced absorption of nutrients
Why did he develop it?
The exact cause is unknown.
People with one autoimmune disease have a higher risk of developing another. Bryan has had autoimmune thyroid disease since age 21, making this diagnosis less surprising.
Long-term risks
Autoimmune Gastritis slightly increases the risk of:

Stomach adenocarcinoma

Type 1 gastric neuroendocrine tumors
The good news is that these neuroendocrine tumors usually grow slowly and are often treatable when detected early.
His treatment
Bryan started with:
* Intravenous iron
* Regular monitoring of ferritin
* Vitamin B12
* Gastrin
* Chromogranin A
* Pepsinogen I/II ratio
He also plans increasingly advanced treatments, including precision immune therapies and experimental approaches, aiming to stop the disease rather than simply manage it.
Bryan Johnson’s story reminds us of an important truth:
No one is healthy enough to guarantee they will never get sick.
A healthy lifestyle does not eliminate every disease.
What it does is increase the chance of:
Detecting problems earlier
Receiving treatment sooner
Preventing long-term complications
The lesson is not to copy every supplement Bryan takes.
The real lesson is to pay attention to small abnormalities, ask questions, and investigate persistent findings.
Sometimes, a single abnormal blood test—like low ferritin—can reveal an important diagnosis years before symptoms appear.

JBdaily