Causes and Treatment of Pernicious Anemia

Pernicious anemia is one of several causes of vitamin B12 deficiency. Congenital pernicious anemia is an autoimmune disorder that impairs your ability to produce or utilize intrinsic factor, a digestive enzyme required for vitamin B12 absorption. Children may inherit pernicious anemia genetically, but symptoms don’t appear until adulthood, over the course of many years.

Another common cause of pernicious anemia is gastritis. Any kind of damage to the stomach wall inhibits your ability to absorb vitamin B12, thus increasing your risk for pernicious anemia.

What causes vitamin B12 deficiency?

Most people who eat plenty of protein-rich foods need never worry about developing pernicious anemia. Your body extracts vitamin B12 from animal-based products like lean beef, liver, chicken, seafood, eggs, and cheese, and stores what it doesn’t need in the liver for later.

Unless you follow a strict vegan or vegetarian diet, refraining from all types of meats, fish, egg, and dairy products, diet alone should not be a cause for vitamin B12 deficiency.

However, other factors can increase your risk for developing pernicious anemia and the debilitating effects of malabsorption. Lifestyle choices, medications, comorbid illnesses, and certain surgeries can prevent you from breaking down vitamin B12 naturally from the foods you eat.

Risk factors for vitamin B12 deficiency include:

  • Having gastric bypass surgery or other gastrointestinal surgeries, such as for treatment of Crohn’s disease
  • Gastrointestinal disorders, such as Crohn’s disease, ulcerative colitis, celiac disease, fibromyalgia, migraines (which cause cyclical vomiting), and lupus
  • Tendency for autoimmune disorders
  • Using certain medications, like protein pump inhibitors (PPIs) for acid reflux or metformin for diabetes
  • Old age
  • Alcoholism


More about intrinsic factor

As mentioned earlier, vitamin B12 deficiency usually results from one of two causes: when you don’t eat enough meat, or when you cannot make (or use) intrinsic factor.

So, assuming you are not a vegan, why can’t you access vitamin B12 from food? What happens to impair your ability to make this essential digestive enzyme, intrinsic factor?

  • You’re born with it. The presence of an intrinsic factor antibody indicates an autoimmune disorder. Instead of allowing intrinsic factor to perform, your body attacks it, perceiving it as a threat. As a result, over time, you become depleted of all “active” types of vitamin B12. (This does not include the amount stored in your liver, which your body is not using.) Untreated, pernicious anemia can cause severe, debilitating nerve damage, cognitive decline, lack of energy, and increased risk for heart attack and stroke.
  • You get autoimmune disorders. Even if you don’t have pernicious anemia, your increases if you have a history for other autoimmune disorders like fibromyalgia, celiac disease, or chronic fatigue syndrome (CFS).
  • You have digestive disorders. The parietal cells of your stomach are responsible for producing intrinsic factor. Any kind of damage to your stomach linings can therefore impair this ability. Chronic diarrhea, acid reflux, cyclical vomiting, stomach ulcers, and gastrointestinal disorders all correlate heavily with pernicious anemia.
  • You’re over 65. As you age, your body slows down, producing fewer bodily fluids. This includes digestive juices required for breaking down vitamins and minerals, such as stomach acids that aid in absorbing vitamin B12. Elderly individuals require vitamin B12 supplements in order to avoid pernicious anemia symptoms like memory loss, fatigue, and mood disorders.


Treating Pernicious Anemia

As pernicious anemia prevents you from absorbing vitamin B12 from foods, it makes sense that vitamin B12 pills are equally ineffective. Instead, doctors prescribe vitamin supplements that enter the blood stream directly, bypassing the need for digestion in the stomach.

For treatment of pernicious anemia, doctors prescribe:

  • Vitamin B12 injections
  • Sublingual vitamin B12, as lozenges that dissolve under the tongue or liquid drops
  • A variety of inedible over-the-counter (OTC) vitamin B12 supplements