Longevity entrepreneur Bryan Johnson reveals he has autoimmune gastritis, a hard-to-diagnose stomach disease

Bryan Johnson, known for his longevity ventures, announced on X that he has been diagnosed with autoimmune gastritis.

The condition is a chronic inflammatory disease where antibodies attack stomach cells that produce acid, leading to poor iron absorption and higher risks of stomach cancer, vitamin B12 deficiency, anemia and neurological problems.

Autoimmune gastritis is estimated to affect about 4% of people worldwide, but it is often missed by gastroenterologists, making Johnson’s disclosure a spotlight on the disease’s diagnostic challenges.