Tech entrepreneur Bryan Johnson diagnosed with autoimmune gastritis

Tech founder and biohacker Bryan Johnson announced on social media that he has been diagnosed with autoimmune gastritis (AIG), an autoimmune disorder in which the body attacks the stomach's acid-producing cells. The diagnosis followed a series of endoscopic examinations and biopsies after Johnson observed persistently low ferritin levels despite multiple oral iron supplements. "Two days later, the results of biopsies came in, showing clear signs of early autoimmune gastritis: early atrophy confined to the acid-producing lining, with the rest of the stomach still spared," he wrote.

Stanford gastroenterologist Dr. Robert Huang explained that AIG can lead to vitamin B12 deficiency, anemia and nerve damage, while also increasing the risk of gastric cancers and neuroendocrine tumors. He noted that the condition may affect up to 2% of adults, a figure that has risen as endoscopic screening becomes more common. Dr. Neil Parikh of Connecticut GI added that blood tests are now able to detect markers of the disease and that treatment focuses on managing nutrient deficiencies through oral supplements, iron infusions or intramuscular B12 injections.

Symptoms often begin with low iron or anemia, and may progress to gastrointestinal discomfort, gastroparesis or small-intestinal bacterial overgrowth. Johnson, who follows a primarily vegetarian diet, said he has not experienced anemia or B12-related symptoms, likely due to his frequent, personalized blood testing. Experts recommend regular surveillance endoscopies for patients with AIG to monitor for potential complications such as gastric cancer or neuroendocrine tumors.