Billionaire Brian Johnson Diagnosed With Autoimmune Gastritis, Reveals Health Battle

Brian Johnson, known as "the healthiest man alive," disclosed on July 6, 2026, that he has been diagnosed with autoimmune gastritis, a chronic condition where the immune system attacks the stomach lining. Johnson, 48, has invested millions in efforts to halt aging but revealed his stomach is "eating itself," shedding light on his ongoing health challenges.

Autoimmune gastritis affects approximately 2% to 5% of the population and causes the stomach to produce less acid and reduce absorption of vitamin B12, according to Professor Adi Lehat, head of the Gastroenterology Institute at Assuta Public Hospital in Ashdod. The disease can progress silently for years, sometimes detected through anemia or iron deficiency, and symptoms may include upper abdominal discomfort, bloating, nausea, and fatigue.

Lehat explained that the immune system mistakenly attacks healthy stomach tissue, primarily affecting specific stomach regions. She noted that long-term vitamin B12 deficiency can cause numbness, sensory loss, or balance issues. Johnson’s diagnosis aligns with his medical history, as he has suffered from hypothyroidism since age 21, a condition often linked with autoimmune gastritis.

Stress and depression, which Johnson has also reported, may exacerbate immune system dysfunction and trigger autoimmune diseases in predisposed individuals. The diagnosis necessitates regular medical monitoring, including gastroscopy and biopsies, to detect potential precancerous changes or stomach cancer early. However, Lehat emphasized that most patients with autoimmune gastritis do not develop malignancies.

Johnson’s public disclosure highlights the complexity of managing chronic autoimmune conditions even in individuals dedicated to optimizing their health and longevity.