Entrepreneur Bryan Johnson reports spending around two million dollars a year tracking almost every measurable feature of his own biology. He is lean, sleeps more than eight hours a night, and publicly claims a “fertility age” in his early twenties at the chronological age of 48. Recently he disclosed a chronic autoimmune condition called autoimmune gastritis, describing it as a situation where “his stomach is eating itself.”
Much of the public commentary has focused on the irony: more than a decade of abnormal blood tests, an extraordinarily intensive self tracking protocol, and a slow autoimmune disease still progressing quietly in the background. That observation is understandable. It is not the most useful lesson to take away. The more important question is why the miss happened, what it says about the difference between measuring a body and understanding one, and what it means for the future of longevity medicine. Let us work through that carefully.
What autoimmune gastritis actually is
The stomach lining contains specialised parietal cells that do two main jobs: they produce gastric acid to help digest food and secrete intrinsic factor, which allows vitamin B12 to be absorbed in the small intestine. In autoimmune gastritis, the immune system produces antibodies against these parietal cells, leading over time to thinning and atrophy of the acid producing mucosa.
As this progresses, stomach acid production falls and B12 absorption declines. Iron absorption is also affected because gastric acid helps with dietary iron uptake. The usual sequence is iron deficiency first, followed by B12 deficiency and a specific type of anaemia known as pernicious anaemia, and in some cases neurological complications from prolonged B12 loss. The condition is often quiet, developing over many years without clear symptoms, which is exactly why it evades detection.
One of the earliest clues is commonly a low ferritin, a marker of stored iron, long before haemoglobin drops. You can be genuinely iron deficient with a normal haemoglobin because the body uses iron stores to preserve circulating levels. Johnson has said that repeated low ferritin results were attributed to other factors and not fully investigated. His eventual diagnosis was made in the standard way: endoscopy with biopsies from several regions of the stomach, combined with blood tests showing markedly elevated anti‑parietal cell antibodies.
Autoimmune gastritis is not only relevant because of iron and B12. It carries an increased risk of certain gastric tumours, including type 1 gastric neuroendocrine tumours and, over time, gastric cancer, which is why early identification and appropriate surveillance matter.
How common it is
Autoimmune gastritis appears to be more common than many people assume and is almost certainly underdiagnosed. Global prevalence estimates vary with the criteria and methods used. Serology based data have historically placed it between 0.3 and 2.7 percent of the general population. More recent analyses suggest a prevalence closer to 3.8 percent worldwide. Johnson himself has quoted a range of 2 to 5 percent, which sits within this spread.
The variation reflects real challenges rather than poor data. The condition is often silent, diagnostic pathways are not completely standardised, and antibody positivity is more common than confirmed disease. For example, a hospital based study reported anti parietal cell antibodies in a substantially larger proportion of people than the proportion with confirmed autoimmune gastritis. That gap between antibody positivity and clinically diagnosed disease illustrates how much of the condition remains hidden.
There are no robust, standalone Australian prevalence figures for autoimmune gastritis. What we can say is that autoimmune disease as a broader category affects around five percent of Australians, based on national reporting. Against that background, it is reasonable to assume that many people in Australia live with autoimmune gastritis without knowing it, including individuals who present with unexplained low ferritin that is treated but not fully explained.
Autoimmune disease and clustering
Autoimmune gastritis sits within a group of more than 80 conditions in which the immune system mistakenly targets the body’s own tissues. Taken together, these conditions affect roughly 4.5 to 5 percent of people globally and a similar proportion in Australia. They are typically chronic, often lifelong, and range from common to rare.
There is a well described sex skew: women carry most of the burden. Older figures suggested that around 80 percent of autoimmune diagnoses occur in women, and more recent work still places the proportion at roughly two thirds. Proposed reasons include differences in sex hormones, X‑chromosome biology, and immune response regulation.
The conditions most commonly encountered include autoimmune thyroid disease (Hashimoto thyroiditis and Graves disease), systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, Sjögren’s syndrome and coeliac disease. Conditions with more equal or male leaning distributions include type 1 diabetes, ankylosing spondylitis and some organ specific conditions such as autoimmune myocarditis.
One theme is particularly relevant to Johnson’s case: autoimmune conditions often cluster. In his situation, the picture is not just iron deficiency. It is iron deficiency, autoimmune gastritis and autoimmune thyroid disease occurring together. This clustering between stomach and thyroid has been described as thyrogastric syndrome, and Hashimoto thyroiditis is several fold more common in people with autoimmune gastritis than in the general population. In standard clinical reasoning, a known organ specific autoimmune diagnosis raises the index of suspicion for a second, and a persistently low ferritin in that setting would typically prompt consideration of autoimmune gastritis among other possibilities.
The longevity lens
This is where the story intersects with longevity medicine and why an accurate account matters more than a dramatic headline. Some of the practices Johnson has described lie at the edge of current medical practice and are not appropriate for most people: exchanging blood with a family member, tracking overnight erections as a biomarker, near complete avoidance of sunlight and extensive daily lists of interventions. Whatever one thinks of individual measures, the broader issue is access and cost. A protocol requiring seven figure annual expenditure and a personalised team of clinicians is not a public health strategy; it is one individual conducting a self experiment. Presenting such an approach as a template for the general population would not be honest.
It would also be inaccurate to dismiss the entire longevity field. Ageing biology does contain pathways with real mechanistic plausibility: cellular senescence, metabolic and mTOR signalling, mitochondrial function and chronic low grade inflammation among them. The difficulty lies in the step from mechanism to outcome in people. A compound can perform exactly as expected in preclinical models and still fail to change meaningful outcomes in humans, or reveal harms only when used at scale. Mechanistic plausibility is a reason to investigate; it is not proof of benefit, and much of the hype in longevity comes from treating those two different claims as if they were the same.
A balanced position recognises three tiers. Some longevity practices remain unproven and should be described as such. Some are plausible and under active investigation and should be labelled as promising but not yet established. Meanwhile, many of the factors that most consistently influence how long and how well people live are not exotic: adequate sleep, maintaining muscle mass, cardiovascular fitness, nutrition, not smoking, managing blood pressure and glucose, and identifying and treating conditions early. Johnson’s situation illustrates this clearly. He has publicly discussed frontier immune therapies for his gastritis, including JAK‑inhibitor and CAR‑T–style concepts that are investigational and in some cases not yet clinically available. Yet the intervention that might have served him best years earlier was simple and low cost: investigating a persistent low ferritin rather than repeatedly attributing it to benign causes.
There is an important irony here. The most measured man alive appears to have been let down not by a lack of advanced technology but by limited follow through on a common, inexpensive marker. More data did not prevent a slow autoimmune condition from progressing. More appropriate interpretation might have.
Longevity medicine and the healthspan gap
Stepping back, the case for longevity medicine is about a gap: the gap between lifespan and healthspan. We are living longer than any previous generation, but additional years are not always lived in good health. Many of those years are spent with disability, chronic disease and dependence rather than vitality. Lifespan has often outpaced healthspan, and closing that gap is the core goal.
This has been framed as “compression of morbidity” since work from James Fries and colleagues in the 1980s: reducing the duration of the period of decline at the end of life rather than simply adding years. The economic argument follows. An ageing population with extended periods of poor health carries substantial costs for health systems, aged care, productivity and families. Each additional disability free year moves in the opposite direction, supporting independence and reducing demand on acute care.
For these reasons, governments and health systems in multiple countries are beginning to invest more seriously in prevention and longevity‑oriented care. This is not about promises of extreme lifespan extension or highly priced niche protocols; it is about evidence guided efforts to extend the healthy, functional portion of life at a scale and cost that can apply beyond a small group of high resource individuals.
How we approach this at AvaElis
This is the space AvaElis was designed to work in, and Johnson’s story aligns closely with how a longevity focused practice can operate in a clinically responsible way.
We begin with fundamentals. The highest value work is often not the newest or most complex test. It is careful baseline assessment, appropriate interpretation and acting on what is found. A persistently low ferritin is investigated rather than simply supplemented. A known autoimmune or thyroid condition prompts appropriate screening for conditions that commonly coexist. This type of work is methodical rather than glamorous, and it is where many real gains in prevention and early detection occur.
We consider advanced diagnostics where they add clear value, rather than for their own sake. More data are only useful if they are interpreted in context and used to guide decisions. Johnson’s decade long experience reminds us that extensive measurement on its own is not enough; the key is the reasoning applied to those measurements.
We are also explicit about the evidence tier of what we offer. Where an approach is well established, we present it as such and anchor it in core health behaviours and standard care. Where an approach is emerging or mechanistically plausible but not yet supported by long term outcome data, we describe it as that, outline potential benefits and risks, and discuss it as part of an informed, shared decision making process. We do not present speculative options as if they were settled, and we do not dismiss carefully designed emerging work as inherently without value.
Our focus is not on the longest list of interventions or the newest devices. It is on separating science from marketing, starting with what is affordable and evidence based, and being transparent about everything else. The goal is more healthy years, explained clearly, and accessible to people who are seeking to understand and improve their health rather than to pursue extreme or unproven protocols.
This article is general information only. It does not constitute personal medical advice and does not replace consultation with a qualified healthcare practitioner. If you have a persistent or unexplained abnormality in your blood tests, including low ferritin, discuss it with your general practitioner or specialist to determine whether further assessment is appropriate for you.