Ted goes to see Dr. Zhou, complaining that he always feels tired and cold. The d

Question

Ted goes to see Dr. Zhou, complaining that he always feels tired and cold. The doctor orders some blood tests. Ted hates needles, but reluctantly gets blood drawn for the tests anyway. At their next appointment a few days later, Dr. Zhou tells Ted that he has pernicious anemia, and will need to take vitamin B12 shots once a month for the rest of his life. The doctor explains more about pernicious anemia, but Ted can’t remember much of what she says because he basically stops listening at the word “injections”. Ted is given one such injection before he leaves the office, and within a few days he begins to feel better.

However, Ted’s uncle Fred scoffs at vitamins, saying that the doctor is a quack, because, “Everybody knows anemia is from not getting enough iron.” Ted will do anything to avoid needles, so instead of going back for more shots, he instead follows Uncle Fred’s advice, and for the next six months he eats lots of red meat cooked in a cast iron skillet.

Six months later, Ted goes back to see Dr. Zhou because his previous symptoms of fatigue and chills have returned, worse than before, and in addition, his hands and feet have gone numb. Dr. Zhou explains that this is another effect of vitamin B12 deficiency, and urges him to take the shots. Ted reluctantly agrees to start taking the shots regularly, and soon his symptoms greatly improve, though he’s left with some degree of permanent nerve damage in his hands and feet.

Why did the extra iron not help Ted?

Ted tries to bargain with Dr. Zhou, saying he will diligently take B12 capsules if he can avoid the shots. Dr. Zhou explains that with pernicious anemia, the problem is not insufficient intake of vitamin B12, but lack of absorption because of lack of something called intrinsic factor.

What is intrinsic factor, and why did Ted’s body stop making it? Why must Ted take shots instead of pills?

Explanation / Answer

Iron did not help: Extra iron did not help Ted because it was not being absorbed during normal digestion by him. Since he lacks intrinsic factor responsible for vitamin B12 (iron-containing) absorption.

Intrinsic factor: It is a glycoprotein, produced by the parietal cells of the stomach, necessary for the absorption of vitamin B12 later on in the ileum of the small intestine. In case, the stomach doesn't secrete enough intrinsic factor; the intestine cannot properly absorb vitamin B12 resulting in its deficiency (condition of pernicious anaemia).

Reason for impaired synthesis: There are conditions which may result in the lack of intrinsic factor in the body. Firstly, weakened stomach lining (atrophic gastritis); secondly, an autoimmune disease when the immune system attacks body's own actual intrinsic factor protein or the parietal cell.

Ted must take shots: Ted needs sufficient vitamin B12 for his survival with pernicious anaemia. For this, he must take shots instead of capsules since he is lacking intrinsic factor making impairing the absorption via the oral route. However, when he takes it intravenously, vitamin B12 is transported directly via blood to the cells producing RBCs.

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