Bryan Johnson Diagnosed With Autoimmune Gastritis: Low Ferritin Despite Normal Blood Counts? Expert Explains

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Bryan Johnson, best known for Project Blueprint, his intensive, data-driven longevity programme has revealed that he has been diagnosed with autoimmune gastritis (AIG), a condition in which the immune system mistakenly attacks the stomach's acid-producing cells.

Johnson said the disease likely contributed to poor iron absorption despite his blood counts remaining normal for years. He publicly announced the diagnosis on June 30, 2026, writing, "My stomach is eating itself."

Photo Credit: Instagram@bryanjohnson_/AI-generated

What Led To The Diagnosis

According to Bryan Johnson, the condition went undetected despite years of intensive health monitoring because he experienced few, if any, stomach symptoms and his hemoglobin levels remained normal. However, he had persistently low ferritin (iron stores) for around 11 years, prompting doctors to investigate further. The evaluation ultimately led to a diagnosis of early autoimmune gastritis.

Bad news #1:

I have an autoimmune disease. My stomach is eating itself.

Bad news #2:

2–5% of people have this, too. Likely more, because it hides.

Good news:

Im going to try and solve it. Will share all.

As a kid, I ate sugar cereal, drank sugary soda, and gobbled down… pic.twitter.com/EbJ8a916uS

— Bryan Johnson (@bryan_johnson) June 30, 2026

Ferritin is a protein that stores iron in the body and reflects the amount of iron your body has in reserve. Since Johnson's diagnosis has drawn attention to the importance of low ferritin, an expert explains why it shouldn't be ignored even when routine blood counts appear normal.

Low Ferritin Even When Blood Counts Are Normal?

Dr. Ramakanth Reddy A, Consultant Medical Gastroenterologist at Gleneagles AWARE Hospital, Hyderabad shares insights on why low ferritin matters even if your hemoglobin and CBC are completely normal.

Photo Credit: PR

He says, "Ferritin measures your iron stores. It drops first. Anemia comes later, usually months after ferritin goes down. So finding low ferritin early is actually a good thing, because it gives us time to figure out why."

What Could Be Causing It?

Dr. Reddy points out a few main buckets:

1. Slow Blood Loss You Can't See

This is what we worry about most in men and women after menopause.

• Stomach ulcer
• Colon polyps or colon cancer
• Angiodysplasia - basically fragile blood vessels in the GI tract
• Damage from long-term painkillers like ibuprofen or naproxen

2. Trouble Absorbing Iron

You might be eating iron but your gut isn't taking it in.

• Celiac disease
• Autoimmune gastritis
• H. pylori infection
• Prior stomach or intestinal surgery, including weight-loss surgery

3. Using More Iron Than You're Getting

• Pregnancy
• Teenage years
• Very heavy periods
• Vegetarian or vegan diet without enough iron
• Donating blood often

Can You Still Have Something Serious In The Gut With Normal Blood Counts?

"Yes. Early colon cancer, celiac disease, and ulcers can all start with just low ferritin. The hemoglobin looks fine at first because your body is using up stored iron. Once the stores are empty, then anemia shows up," Dr. Reddy remarks.

What's Usually Recommended Next?

"For adult men and postmenopausal women with confirmed low ferritin, most GI guidelines say you should check for a source of blood loss in the gut. That often means:

• Upper endoscopy to look at the stomach and upper intestine
• Colonoscopy to look at the colon

This is recommended even with normal hemoglobin, especially if ferritin is quite low - under 30 ng/mL, or under 45 ng/mL by some guidelines or if you have symptoms or risk factors," he points out.

Typical First Steps Before Scopes

Dr. Reddy advises the following:

• Repeat iron tests - ferritin and transferrin saturation to confirm
• Celiac blood test - tTG-IgA plus total IgA
• Test for H. pylori if you have stomach issues
• Review diet and periods - are you getting enough iron? Are periods very heavy?

Decide on endoscopy based on your age, sex, symptoms, and risk

Don't Ignore Low Ferritin

Dr. Reddy concludes that low ferritin isn't something to brush off just because your CBC is normal. For some people it's diet or periods. For others it's the first clue to something in the GI tract.

The best move is to take this report to your primary doctor or a gastroenterologist. They'll look at your full history and decide if you need iron, diet changes, more blood work, or an endoscopy.

Bryan Johnson's recent diagnosis of autoimmune gastritis has highlighted why persistently low ferritin shouldn't be overlooked, even when routine blood counts appear normal. As Dr. Reddy explains, low ferritin can be an early clue to an underlying condition, making timely medical evaluation important to identify the cause and begin appropriate treatment.

Disclaimer: The information provided in this article is for general informational and educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or a qualified healthcare provider with any questions you may have regarding a medical condition.