Bryan Johnson has publicly revealed that he has Autoimmune Gastritis, his ferritin has been low for 11 years, and his stomach has been slowly losing function in the background. He’s breaking down. In his own thread, he admitted that a plant-based diet meant his iron was the hard-to-absorb, non-heme kind, and that food, supplementation, timing tricks, and different formulations still did not make his iron stick.
This is not some random footnote. This should make people question the whole Blueprint philosophy.
The most measured man alive spent 11 years missing one of the most basic signs that his body was not okay.
What Autoimmune Gastritis actually means
Autoimmune Gastritis, or AIG, is an immune-mediated condition where the immune system attacks the stomach’s parietal cells. These cells help produce stomach acid and intrinsic factor, which is needed for B12 absorption. As the stomach lining atrophies, people can lose stomach acid, lose the ability to absorb key nutrients, and eventually develop iron deficiency, B12 deficiency, pernicious anemia, digestive dysfunction, and other serious issues that require surveillance.
The low ferritin part matters because iron deficiency can show up before B12 deficiency and before classic anemia. Ferritin is stored iron. Hemoglobin can still look normal while the reserve tank is being drained.
Bryan’s ferritin was low for 11 years. That is a decade of his body telling him something was wrong.
The bigger issue is that the same philosophy he sells as “optimization” may be the exact reason he missed the basics.
Mistake #1: Avoiding animal foods
This is the most obvious problem.
Bryan removed the most nutrient-dense foods on planet earth. I’ve met him a few times and asked him point blank, “if you want to live forever, why do you avoid the most nutrient dense foods?” He had no answer. He just looked at me blankly for what seemed like forever until his sidekick chimed in with something about how good is biomarkers are.
Meat. Organs. Eggs. Seafood. Shellfish. Dairy.
These are not random “old-fashioned” foods. They are the primary foods humans have relied on for deep nutrition. They provide complete protein, essential fats, fat-soluble vitamins, minerals, and compounds that are either missing from plants or much harder to get in usable amounts.
Animal-source foods provide highly bioavailable nutrients that are commonly lacking around the world: high-quality protein, iron, zinc, vitamin A, vitamin B12, calcium, iodine, DHA, and other nutrients that matter for growth, development, immune function, metabolism, fertility, and long-term health.
Plant-based diets can look good in a nutrition app, but the app is not your biology. Reviews on vegan and vegetarian diets repeatedly flag B12, vitamin D, iron, zinc, calcium, iodine, selenium, and omega-3s as nutrients of concern.
That should tell us something.
A diet that requires fortified foods, supplements, and constant micromanagement to avoid basic deficiencies is not the ancestral human default, it’s a modern luxury that I think is based on propaganda and ideology.
And in Bryan’s case, the construction failed in the most obvious place: iron.
Plants do not provide heme iron. Animal foods do. Heme iron is more bioavailable than non-heme iron and is less affected by inhibitors in the rest of the meal. Non-heme iron from plants is more variable and more easily blocked by compounds like phytate and polyphenols.
So if your ferritin is low for 11 years while you refuse the richest and most bioavailable iron foods on earth, the diet has to be part of the conversation.
This goes way beyond iron. Plant-based nutrition often counts precursors as if they are the finished nutrients the body actually uses. Beta-carotene from plants is treated like vitamin A, but the active form is retinol, which comes from animal foods. ALA from plants is treated like omega-3, but the critical forms are EPA and DHA, which come from seafood and animal foods. Non-heme iron from plants is treated like heme iron, but heme iron only comes from animal foods and is far more usable. Plant protein is treated like animal protein, but it is generally less complete, less digestible, and often packaged with starch, fiber, and anti-nutrients.
This is the central problem with plant-based nutrition: it gives you the “maybe your body can convert it” version of nutrients. Animal foods give you the real thing.
Nutrition is not what appears in a database. Nutrition is what your body can absorb, convert, and use.
Mistake #2: Pretending plant-based equals healthy
The mainstream has trained people to think “plant-based” is automatically healthy.
I disagree.
I am not anti-vegetable. I eat vegetables with every meal. I like vegetables. I think they can be useful, enjoyable, and part of a healthy diet.
But plant foods should complement animal foods, not replace them.
There is a huge difference between eating some seasonal plants with meat, eggs, or seafood, and building an entire health identity around greens, grains, legumes, seeds, nuts, plant protein, fake meats, fiber powders, fortified foods, and supplements while removing the foods that actually deliver primary nutrition.
Plants are not inert. They are living organisms with defense compounds. Some are useful in the right dose and context. Some are irritating for certain people. Some reduce mineral absorption. Some become a problem when concentrated into smoothies, juices, powders, extracts, and daily mega-servings.
I learned this the hard way. Around 12 years ago, when I was starting my health journey, I drank kale and spinach smoothies daily because I thought I was being healthy. That gave me oxalate issues, and I still deal with problems from it today.
This is not imaginary. There are published case reports of oxalate nephropathy linked to high-oxalate green smoothies or vegetable juice cleanses. These cases are not common, but they prove the broader point: concentrating huge amounts of “healthy” plant foods can backfire.
Fiber is another example. Fiber can be helpful, especially when the alternative is ultra-processed junk. But more fiber is not automatically better. In IBS and other digestive conditions, fiber type and dose matter. Reviews note that fiber can cause bloating and distension, and fermentable fibers can make symptoms worse in sensitive people.
Then there are anti-nutrients like phytates, oxalates, tannins, lectins, and other plant compounds that can reduce mineral bioavailability or irritate certain people depending on dose, preparation, gut status, genetics, and the rest of the diet.
The pesticide issue may be even more important.
A plant-heavy modern diet is not just “plants.” It can mean higher exposure to pesticide residues, herbicides, fungicides, insecticides, processing residues, and compounds used in industrial agriculture. This matters because the gut microbiome is tied to immune regulation, digestion, gut barrier function, inflammation, metabolism, and mood.
Reviews have raised concern that pesticides can alter gut microbiota composition and function, and The ISME Journal has discussed pesticide exposure and the microbiota-gut-brain axis. Low-dose glyphosate research in mice found changes in gut microbes, reduced beneficial bacteria, altered short-chain fatty acid pathways, and increased pro-inflammatory markers in this glyphosate and gut microbiota study. Another review concluded that glyphosate residues could contribute to dysbiosis.
I am not saying every pesticide exposure causes autoimmune disease. I am saying it is insane to ignore pesticides, the microbiome, and the modern food environment when we talk about gut dysfunction and immune dysregulation.
Organic helps, but organic does not mean chemical-free. A systematic review found organic foods tend to have lower levels of synthetic pesticide residues, and an organic diet intervention found reductions in urinary pesticide metabolites. But the USDA organic program still has a National List of Allowed and Prohibited Substances, meaning organic production can still use certain allowed substances.
This may be one reason so many people say they can eat bread or dairy in Europe and feel fine, then come back to the U.S. and feel terrible. I do not think Europe is magic. It could be pesticide use, wheat varieties, glyphosate practices, additives, fermentation time, lower ultra-processing, more walking, less stress, slower meals, or a completely different food culture. But it is obvious to me that the modern American food environment is not normal.
The ex-vegan pattern also fits here.
I hear from ex-vegans constantly. They went vegan to be healthy, ethical, clean, anti-aging, or environmentally conscious. At first, many felt better because they removed junk food. Then months or years later came the problems: fatigue, low ferritin, B12 issues, hormone issues, low libido, gut problems, bloating, skin issues, anxiety, brain fog, poor recovery, dental issues, and autoimmune flares.
Then they add back animal foods, and many feel like their body turns back on.
I do not need a randomized trial of every autoimmune condition to say this pattern makes sense. If you remove the most nutrient-dense and bioavailable foods, rely heavily on plant compounds that can be irritating for some people, increase exposure to agricultural chemicals, and depend on supplements to fill in the gaps, susceptible people are going to run into problems.
Complex diseases have many causes. Genetics, infections, immune regulation, gut health, micronutrient status, pesticide exposure, stress, sleep, light exposure, and other environmental triggers can all play a role. We will never know for sure what caused his condition, but my humble opinion is that his protocols have been working against his own biology.
Mistake #3: Living against nature
Bryan’s diet is only one piece of the bigger problem.
Read on at: https://foodlies.substack.com/p/the-most-optimized-man-alive-is-breaking