Bryan Johnson Reveals Autoimmune Gastritis Diagnosis, Eyes CAR-T
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- Bryan Johnson announced on X that he has autoimmune gastritis, an autoimmune disease that destroys the acid-producing cells in his stomach and prevents iron absorption; the 48-year-old biohacker said his team is exploring experimental CAR-T therapy despite no specific studies for this condition
- Autoimmune gastritis affects an estimated 4% of people worldwide but is notoriously difficult to diagnose, with experts saying gastroenterologists often fail to recognize it; patients are 13 times more likely to develop neuroendocrine tumors
- Johnson's earliest symptom was consistently low ferritin levels, while hemoglobin and hematocrit levels appeared normal — a pattern experts say allowed the condition to be easily dismissed; definitive diagnosis requires an upper endoscopy with biopsies
- Standard treatment options are limited: patients manage with oral or intravenous iron, monitor for stomach cancers, and have no specific cure available, though experts at the Medical College of Wisconsin called CAR-T investigation "the best line" for finding one
- Johnson was 48 and overdue for a colonoscopy when he finally received one, though the U.S. Preventive Services Task Force only lowered the recommended screening age from 50 to 45 in 2021
- Experts called Johnson's speculation linking his childhood diet of fast food and sugary cereals to the disease "highly speculative," though they confirmed his autoimmune thyroid disease does correlate with higher autoimmune gastritis risk
- Johnson's announcement — with his own diagnosis relieving him — could spotlight the need for biopsies in patients with iron-deficiency histories, said Medical College of Wisconsin pathologist Toby Cornish
Why it matters: Johnson, who called himself "the most biologically measured person ever" and spent $2 million on medical treatments in 2023, was still 48 and overdue for a colonoscopy when he received his diagnosis — illustrating that even the most health-optimized individuals can miss routine screenings, and that autoimmune gastritis is so hard to detect that standard blood markers like hemoglobin can appear normal while ferritin quietly signals the underlying disease for decades.
