As you may know, pernicious anemia can cause devastating effects if you don’t treat its signs and symptoms early enough. But, what causes pernicious anemia in first place? What is the source of this cruel disease? For a start, we do know:
Pernicious anemia primarily affects people of northern European ancestry. It’s rare in children and infants. Onset typically occurs after age 35, and incidence increases with age. It affects about 2% of people older than age 60.
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The next thing to know is that pernicious anemia results from a deficiency of B12 caused by the body being unable to absorb the vitamin. Most of the time, this is the result of autoimmune attacks on the stomach. Let’s see what that means.
The Causes of Pernicious Anemia
People often ask us, what vitamin deficiency causes pernicious anemia? But that’s not the right question. The lack of B12 is a byproduct, not the cause. Again, since this is a key point. Pernicious anemia is caused by a deficiency of the gut’s ability to absorb B12, often due to autoimmune issues. The lack of B12 is not a cause, but a side effect.
Autoimmune issues occur when your immune system – your body’s guard against intruders – creates antibodies that attack your own cells. In PA, those are antibodies that attack your intrinsic factor (IF), a protein needed for the absorption of B12. Or they are antibodies that attack the stomach’s parietal cells, which create IF in first place.
Only when B12 combines with intrinsic factor can the B12 move to the ileum of the small intestine for absorption. In pernicious anemia, there is not enough intrinsic factor to move and absorb the B12. This is why the only treatment to bypass that defect are B12 shots straight into the bloodstream. PA patients need them for life.
Why Do Autoimmune Attacks Occur?
We’re not 100% sure. Leading researcher Dr. Alessio Fasano (discoverer of zonulin, a protein responsible for regulating intestinal tight-junctions) has put forward the idea that the main cause of autoimmune disorders is leaky gut (impaired intestinal barrier function). Some compounds, like gluten, can harm the lining of the gut.
To see a study that shows how diet can affect inflammatory bowel disease, another autoimmune condition, check out our PA diet page. If leaky gut is indeed the leading cause of autoimmune diseases, then this diet should help it heal.
Of course, there is also your inborn, hereditary predisposition to develop autoimmune reactions in first place. If you read about the etiology of pernicious anemia you will see that it mainly affects older people of Northern European descent. Even more so when they have a family history of autoimmune conditions. Genetics play a big role.
Other Causes?
Weight loss surgery (gastrectomy) may obliterate many of the parietal cells and lead to a condition that mimics pernicious anemia – where you simply don’t have enough intrinsic factor. That is dangerous, because unlike classic cases of PA, your tests may not show any antibodies to help establish the diagnosis of pernicious anemia.
Did you know?
The malabsorption of B12 can also occur in the small intestine after intrinsic factor has moved the B12 in there. But it’s not pernicious anemia. There are no PA antibodies. And it is curable! But what causes that malabsorption?
Other things that eat your B12 before your body can absorb it. It could be bacteria or tapeworm infection (eating undercooked, infected fish is one cause). Laughing gas and some medicines can also drain B12 levels.
What Causes Pernicious Anemia In Children?
When it comes to children, what is pernicious anemia caused by? PA does not usually appear until the age of 30. Rarely though, babies are born with congenital pernicious anemia, in which their bodies can’t produce the intrinsic factor they need. This is an inherited disorder with grave outcomes if not treated right away.
As you see, at any age, pernicious anemia is related to impaired absorption of B12 because of IF issues. It is very serious. Never delay treatment. No matter the pernicious anemia cause, you’re going to have to inject, likely for life. If you neglect it, the myelin sheath around your nerves will slowly strip off, and then all hell breaks loose.
B12 shots save the lives of PA patients.
