Why did the extra iron not help ted? what is intrinsic factor, and

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?