Health Information & Chronic Conditions

Why Do at Least Half of People With PA Have Iron Deficiency With or Without Anemia?

2026-08-082026-08-08 by Laurel Fitzhugh

Iron deficiency and pernicious anemia both result from destruction of parietal cells.

Gastritis destroys parietal cells

Parietal cells make two things: intrinsic factor and hydrochloric acid. Gastritis has several possible causes: autoimmune attack, H. pylori, long-term PPI use, or gastric surgery. Regardless of which one is responsible, the damage takes out acid and intrinsic factor production together.

The acid connection is specifically relevant for iron absorption. Food iron is mostly ferric (Fe3+), and stomach acid helps keep it soluble and facilitates its reduction to ferrous (Fe2+), the form DMT1 transporters in the duodenum can absorb. Achlorhydria impairs that process. So even with adequate dietary iron, absorption drops.

Oral and Sublingual B12 in Pernicious Anemia

2026-06-272026-06-22 by Laurel Fitzhugh

Sublingual B12 raises blood numbers. It has never been shown to protect a single nerve. There is no reason to think it prevents permanent nerve damage.

PA and B12 Deficiency Run in Families

2026-06-052026-06-05 by Laurel Fitzhugh

Family sitting together in a forest with parents holding hands behind their children.

Pernicious anemia has documented familial prevalence. First-degree relatives of PA patients carry a risk four times higher than the general population, and among siblings the figure is higher still — roughly six times the baseline rate. This reflects shared genetic architecture that shapes immune function across generations. B12 deficiency more broadly also clusters in families … Read more

Polyautoimmunity and Helminthic Therapy

2026-05-30 by Laurel Fitzhugh

Autoimmune diseases often cluster within the same individual and family. This article examines helminthic therapy through the lens of immune training, microbiome ecology, and transgenerational biology, exploring evidence that the absence of co-evolved organisms may contribute to immune dysregulation across diseases and generations. It reviews current research on regulatory T cells, the microbiome-immune axis, maternal transmission, and the broader implications of biome depletion for understanding autoimmune disease.

No Market, No Attention: Pernicious Anemia and the Cost of Invisibility

2026-06-052026-02-27 by Laurel Fitzhugh

Pernicious anemia is one of the clearest cases in contemporary medicine where everything required for good outcomes exists — the diagnostic tools, the treatment, the evidence base — and the outcomes remain poor anyway. The gap between what medicine knows and what medicine does is not a gap in knowledge.

History and Misdiagnosis of Pernicious Anemia

2026-06-052026-02-27 by Laurel Fitzhugh

How a 19th-Century Disease Model Still Shapes Modern Care Pernicious anemia has been misunderstood since it was first described. That misunderstanding did not persist because of a lack of scientific progress, but because early observations hardened into a disease model that medicine never fully revised. The result is a condition that remains misdiagnosed, underdiagnosed, and … Read more

Why Do I Feel Worse After Starting B12 Treatment?

2026-08-122026-02-22 by Laurel Fitzhugh

After years of symptoms and possibly decades of misdiagnosis, starting B12 injections should bring relief. Sometimes, though, people feel worse instead of better. For many people, it feels like “two steps forward, one step back.”

Possible Explanations

About 10% of people notice their symptoms intensify in the first few weeks after starting B12 treatment. For some people, symptoms like tingling, burning, or shooting nerve pain may increase. Others notice brain fog, agitation, or mood changes. Several explanations for this pattern have been proposed. None has been confirmed by direct research.

B12 Beyond the Basics: Cellular Resistance and Functional Deficiencies

2026-08-122026-02-21 by Laurel Fitzhugh

Vitamin B12 is essential to DNA synthesis, red blood cell formation, neurological integrity, and methylation — the process by which the body converts homocysteine to methionine. Deficiency at any of these levels can produce serious and, if uncorrected, permanent damage: megaloblastic anemia, peripheral neuropathy, spinal cord degeneration, cognitive impairment, and psychiatric symptoms that are frequently misattributed to primary mental illness.

The problem facing both patients and clinicians is that B12-related illness is not a single condition with a single cause. Pernicious anemia (PA) — the best-known cause of B12 deficiency — results from an autoimmune failure of absorption. But a growing body of evidence describes a different category of B12-related illness in which absorption is intact and blood B12 levels appear normal, yet symptoms of deficiency persist. This second category, sometimes called B12 resistance or cellular resistance, reflects failures in transport, cellular uptake, or intracellular conversion after B12 has entered the bloodstream.

PA: 𝗗𝗲𝗽𝗿𝗲𝘀𝘀𝗶𝗼𝗻, 𝗔𝗻𝘅𝗶𝗲𝘁𝘆, 𝗮𝗻𝗱 𝗢𝘁𝗵𝗲𝗿 𝗣𝘀𝘆𝗰𝗵𝗼𝗹𝗼𝗴𝗶𝗰𝗮𝗹 𝗘𝗳𝗳𝗲𝗰𝘁𝘀

2026-06-052026-02-06 by Laurel Fitzhugh

𝗗𝗲𝗽𝗿𝗲𝘀𝘀𝗶𝗼𝗻, 𝗔𝗻𝘅𝗶𝗲𝘁𝘆, 𝗮𝗻𝗱 𝗢𝘁𝗵𝗲𝗿 𝗣𝘀𝘆𝗰𝗵𝗼𝗹𝗼𝗴𝗶𝗰𝗮𝗹 𝗘𝗳𝗳𝗲𝗰𝘁𝘀

𝗜𝗻𝘁𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻

Pernicious anemia often affects how a person feels, thinks, and emotionally regulates long before it is recognized as a vitamin B12 disorder.

People with pernicious anemia may experience persistent anxiety, low mood, emotional volatility, intrusive worry, difficulty concentrating, and a strong internal sense of physiological unease. Health-focused anxiety—ongoing concern about bodily sensations and symptoms—is a common expression of these changes.

These psychological effects arise from the way pernicious anemia impacts the nervous system.

Pernicious Anemia and Subacute Combined Degeneration

2026-06-052026-01-24 by Laurel Fitzhugh

Pernicious Anemia Is a Neurological Disease

I. Pernicious Anemia Is a Demyelinating Neurological Disease

Pernicious anemia (PA) is an autoimmune disorder in which vitamin B12 cannot be adequately absorbed or utilized, leading to progressive neurological injury.

Autoimmune failure of vitamin B12 absorption disrupts methylation and fatty acid metabolism essential for myelin maintenance and repair, producing central and peripheral demyelination, tract-specific spinal cord injury (classically subacute combined degeneration), and widespread cognitive, emotional, and psychiatric manifestations. These neurological effects frequently precede anemia and may occur in its absence.

Pernicious anemia (PA) typically has an insidious onset, with early symptoms that are nonspecific and easily misattributed. As a result, diagnosis is often delayed several years from symptom onset to receive a correct diagnosis, and a substantial proportion are initially misdiagnosed or not diagnosed at all. During this period, neurological injury continues to accumulate. Clinicians are therefore often faced with patients who already have advanced neural involvement by the time the underlying disorder is recognized.

Because myelin repair is metabolically demanding and time-dependent, outcomes depend not only on correcting cellular B12 deficiency but on interacting system constraints rather than hematologic markers alone.

Understanding how this injury unfolds, and why its effects vary so widely, requires looking beyond any single pathway.

Gastritis destroys parietal cells

Possible Explanations

Pernicious Anemia Is a Neurological Disease

I. Pernicious Anemia Is a Demyelinating Neurological Disease

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