Bryan Johnson is battling THIS rare autoimmune disease: Biohacker shares his health issue in recent post

For a while now, Bryan Johnson has been on a mission to outsmart aging, and the world has been taking notes. He’s the American entrepreneur and venture capitalist turned longevity enthusiast who spends millions on tracking every tiny detail of his health, fixates on the latest anti-aging science, and follows strict routines most people would find impossible — all to squeeze every extra year out of life he can.However, in a twist even he probably didn’t expect, Johnson recently shared he’s been diagnosed with an autoimmune disease — Autoimmune Gastritis (AIG). It’s a chronic disease where your own immune system attacks your stomach lining.In a recent X post, Johnson wrote, “My stomach is eating itself.”Quite expectedly, this latest health update from Johnson has taken the internet by storm.Why?Well, Johnson has access to science and technology that most of us can only dream of. If a rare autoimmune disease can sneak up on him, that indeed is a matter of concern.So, what disease is it? And what do we know about it so far?Let’s unpack.Bryan Johnson’s autoimmune disease: What exactly is it?Johnson shared that he is suffering from Autoimmune Gastritis (AIG) in his X post.What is this AIG?AIG is a chronic and progressive condition. In this autoimmune disease, your immune system makes a mistake and targets your stomach’s parietal cells — these are the cells that make stomach acid and a protein called intrinsic factor (which you need to absorb vitamin B12). As the attack continues, these cells die off. That leads to less stomach acid, problems absorbing nutrients, and, over time, your stomach tissue thins and weakens.Unlike regular gastritis, which is usually caused by infections or something you ate, AIG is an autoimmune disease.Johnson wrote in his post, “As a kid, I ate sugar cereal, drank sugary soda, and gobbled down fast food. I had a few healthy years in my early 20s but then became a young father of three and began building a business.”He admitted, “Juggling that stress and grind, I let my health slip and gained 40 lbs. Within a few years I’d fallen into a deep, chronic depression,” adding, “my body began developing an autoimmune process affecting my thyroid and then my stomach lining.”Research published in Nature Reviews Disease Primers details that in AIG, immune cells target the stomach's parietal cells and eventually destroy them. For the unversed, these cells produce both stomach acid and intrinsic factor, which is a protein required for vitamin B12 absorption. AIG is driven by an immune attack against the stomach's proton pump (H+/K+ ATPase). That makes it fundamentally different from common gastritis, which is largely caused by infections or dietary irritation.Now, this really matters for Johnson because his “Blueprint” protocol relies on everything in his body running smoothly, especially how well he absorbs nutrients.Early signs of AIG: The red flags to watch forThe reason AIG is so tough isn’t just what it does — it’s how quietly it happens. Most people don’t even notice symptoms until the damage is pretty far along. Johnson revealed that he learned he had AIG only recently, though his body has probably been dealing with it for years.Johnson wrote, “My hypothyroidism got diagnosed when I was 21 years old with a routine blood draw. That enabled me to begin proactive management, supplementing levothyroxine and Armour Thyroid. They are the hormones my body should be producing on its own but wasn’t.”He added, “By taking these pills daily, my body was able to operate as though my thyroid was functioning properly. What I didn’t know was that something else was going on inside my body: my stomach had begun attacking itself. But there was no routine test to find out and I didn’t have any symptoms.”So, when did he figure out his diagnosis?“I just discovered it in May,” Johnson wrote, adding, “I'm unsure how long I've had it. AIG causes irreversible damage: nutritional deficiency, anemia, and over a long horizon, elevated cancer risk. When AIG is discovered today, standard medical care concedes defeat, stating that nothing can be done except managing the condition, no matter how awful or lethal the effects.”Now, per research, usually, iron deficiency shows up before B12 deficiency in AIG, because you need stomach acid to absorb iron. As acid production drops, iron just doesn’t get into the system, even if you’re eating plenty.Johnson never felt ill. In his words, “Looking back over the past few years, I can now see the early signals we were picking up in measurement but hadn’t connected the dots.”However, he shared, “For 11 years, I’ve had low ferritin, without anemia. We continually tried to raise my iron levels with food and supplementation but nothing would work.”“On the surface, my low ferritin was easy to dismiss by most standards of care. My hemoglobin and hematocrit were normal. Ferritin measures stored iron, while hemoglobin measures circulating iron, and because the body drains its reserves first to keep hemoglobin normal, you can be fully iron deficient with a perfectly normal hemoglobin and hematocrit,” Johnson worte, “This is why my low ferritin kept getting dismissed: the numbers that define anemia looked fine, so no one asked why my iron reserves wouldn't refill.”Why does iron matter so much? It’s about more than keeping anemia away. Iron fuels oxygen transport, muscle work, and cellular energy. For a guy working this hard to optimize body and brain, chronic iron loss is a real problem.And it doesn’t stop with iron or B12. AIG often drags down vitamin C, vitamin D, calcium, and folate too — all the nutrients that are key for bones, immunity, heart health, and aging well.This B12 loss might be the bigger long-term threat. When parietal cells get wiped out, intrinsic factor drops, and absorbing B12 becomes tough, opening the door to pernicious anemia. Without enough B12, the risks include cognitive decline, nerve damage, fatigue, and mood issues — the exact sort of problems Johnson is fighting against.Potential risk factorsThere’s another serious concern that ties directly to longevity. AIG bumps up your risk of certain stomach cancers, particularly gastric adenocarcinoma and gastric neuroendocrine tumors. Years of silent inflammation and atrophy increase this risk. Johnson knows this and says he’s keeping a close eye on cancer as part of managing his condition.Truth is, AIG exposes a blind spot in longevity science. Johnson’s spent years measuring everything possible, but AIG still went undetected for ages. That’s a pretty powerful reminder, even in the world’s most elaborate health experiment, some things still fly under the radar. The “diagnostic delay” problem is real; symptoms don’t always show up, and by the time they do, the damage is often done.How common is AIG?For a long time, doctors thought AIG was unusual. Now, evidence suggests it could be a lot more common. Johnson shared, “2–5% of people have this, too. Likely more, because it hides”Most AIG victims remain undiagnosed because you need specialized tests or biopsies to catch it. Many people have autoimmune antibodies but never realize what’s going on until something goes wrong. AIG often links up with other autoimmune diseases, like thyroid disorders, type 1 diabetes, vitiligo, Addison’s disease — the list goes on.Johnson’s no exception; he’s had hypothyroidism since he was 21. His doctors eventually noticed the connection between his thyroid issues and stomach problems, which is a pattern known as “thyrogastric syndrome.”How this impacts Bryan Johnson’s longevity journeyNow, this one’s the million-dollar question here.For most, AIG is a tough chronic disease. For Bryan Johnson, it’s an even bigger hurdle because it lands right in the middle of his core strategy.What happens to the biohacker’s quest to an eternal life?After all, AIG sabotages nutrient absorption: iron goes first, but as B12 drops, fatigue, memory trouble, nerve damage, and brain fog follow. These problems matter more in longevity science. Keeping nutrients in balance is crucial for muscle, metabolism, the brain, and aging. And since Johnson’s entire program is designed around precision, anything that scrambles those measurements is bad news.The decline in stomach acid, too, isn’t just about digestion. Low acid means problems breaking down food, a higher risk of getting sick from microbes, and less mineral absorption. Over time, it’s a domino effect, messing with systems far beyond the gut.Moreover, in the long run, the threat of cancer (especially neuroendocrine tumors) is a cloud that hangs over anyone with AIG. Johnson’s medical team plans to track tumor markers (like gastrin and chromogranin A) closely, hoping to catch any issues early.Is there a cure for AIG?Right now, no.There’s no cure or way to reverse AIG. Treatment means monitoring the disease, replacing things you’re deficient in, doing regular endoscopy checks, and dealing with problems as they show up.Johnson shared that he already fixed his iron with IV infusions and now focuses on keeping his nutrients in range. But true to form, he isn’t satisfied with just that. Currently, he’s exploring advanced immune system testing, experimental treatments, and any cutting-edge technology that might help — from regulatory T-cell approaches to cellular therapies.Most of these ideas are new and unproven, but Johnson thinks the future of medicine (immunology, AI, engineered cells) will eventually change the game for diseases like AIG.Get the latest movie news, reviews, and celebrity updates. Download the TOI App.