Bryan Johnson revealed that he has been diagnosed with autoimmune gastritis (AIG), a condition in which the immune system attacks the stomach's acid-producing cells, after years of unexplained low ferritin levels that did not improve despite diet and supplements. He shared that the disease, which may affect 2–5 per cent of people and often remains hidden, can lead to vitamin B12 deficiency, iron deficiency, anaemia, and an increased long-term risk of stomach complications. Experts Dr Ruby Tapari