What is autoimmune gastritis, the condition Bryan Johnson says he has?
Longevity entrepreneur Bryan Johnson has said that his stomach 'is eating itself' after being diagnosed with autoimmune gastritis: so what do we know about this rare condition?
 "What is autoimmune gastritis, the condition Bryan Johnson says he has?")
Longevity entrepreneur Bryan Johnson, who has built a global following through his ambitious anti-ageing regimen and "Don't Die" movement, has revealed that he has been diagnosed with autoimmune gastritis. In a long and detailed post on social media platform X, Johnson said, "My stomach is eating itself."
Bryan Johnson, whose X profile carries the quote, "Conquering death will be humanity's greatest achievement", said the diagnosis came after years of persistently low iron levels despite dietary changes and getting supplements. According to him, routine investigations initially failed to identify the cause until specialised blood tests and stomach biopsies confirmed the condition.
What is autoimmune gastritis?
According to the US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), autoimmune gastritis occurs when the immune system mistakenly attacks healthy cells in the stomach lining. The condition is chronic and typically non-erosive, gradually damaging the stomach's acid-producing parietal cells, which are important for digestion.
As the condition progresses, reduced stomach acid can impair iron absorption, eventually leading to vitamin B12 deficiency.
Why is it difficult to diagnose?
The NIDDK says autoimmune gastritis itself may not cause symptoms. When symptoms develop, they are often related to complications such as vitamin B12 deficiency, iron deficiency or anaemia.
These may include fatigue, weakness, dizziness, headaches, pale skin, numbness or tingling in the hands and feet, problems with balance, confusion or difficulty thinking, nausea, vomiting, loss of appetite and weight loss.
Because some people remain symptom-free, the disease may go unnoticed until nutritional deficiencies or stomach damage are identified during medical evaluation.
Is there a cure?
According to the NIDDK, treatment for autoimmune gastritis focuses on managing complications rather than reversing the disease. Depending on the patient's condition, treatment may include vitamin B12 supplements, iron supplements, or folic acid supplements to address nutritional deficiencies.
The US National Cancer Institute (NCI) notes that autoimmune gastritis is associated with an increased risk of gastric cancer, and some patients may require monitoring based on their condition.
Who is Bryan Johnson?
Bryan Johnson is an American technology entrepreneur, investor and longevity advocate best known for his efforts to slow biological ageing.
As an entrepreneur, he founded online payments company Braintree, which acquired Venmo before PayPal bought Braintree for $800 million in 2013. He later founded Kernel, a neurotechnology company focused on developing advanced brain-monitoring devices.
In recent years, Johnson has become known for "Project Blueprint", an intensive health programme involving strict diet, exercise, sleep, medical testing and continuous monitoring of biological markers. He has publicly shared many aspects of his regimen, claiming it is designed to reduce his biological age and improve long-term health.
Bryan Johnson's unconventional longevity routine
Johnson has become one of the world's best-known longevity advocates for the extraordinary measures he takes in an attempt to slow biological ageing. According to his Netflix documentary “Don't Die: The Man Who Wants to Live Forever,” he spends around $2 million a year on his anti-ageing programme, following a daily routine that includes a carefully measured diet, intensive exercise, frequent medical testing and dozens of supplements.
The documentary also shows Johnson taking more than 50 pills a day, undergoing regular MRI scans, blood tests, other health assessments, and trying experimental interventions such as gene therapy, plasma transfusions and fat transfers.
One of his most widely discussed experiments was a multi-generational plasma exchange involving Johnson, his teenage son and his father. He later said that the procedure did not produce the benefits he had hoped for and discontinued it.
According to his website, Johnson’s daily routine is equally regimented. He typically wakes at 4:30 am, eats all of his meals by around midday, avoids alcohol and caffeine, prioritises what he calls "perfect sleep" with an early bedtime, and closely monitors hundreds of biological markers using wearable devices and regular laboratory tests.