DEAR DR. BLONZ: I have pernicious anemia, for which I receive B12 injections. Why is it that intrinsic factor cannot be synthesized and introduced into the body by injection or pills? It seems as though that would be better. -- T.D., Anderson, South Carolina
DEAR T.D.: As you know, but other readers may not, two separate components are needed for vitamin B12 to be absorbed. The first is the vitamin itself, and the second is a protein manufactured by the body that is called the “intrinsic factor.” That factor links with vitamin B12 and provides the escort that carries it through the absorptive surface of the intestines. Without its intrinsic factor, little, if any, vitamin B12 would ever get into your system.
Pernicious anemia, which only occurs in about 2% of individuals, is when the stomach produces an insufficient amount of that intrinsic factor protein. When this is the case, dietary sources of vitamin B12 do not get absorbed. We cannot get the same effect from taking intrinsic factor as a dietary supplement, as it will get broken down like other nutritional proteins.
To date, the most workable treatment for pernicious anemia is the periodic injection of the preformed vitamin B12. The strategy should be worked out with your health professional, who can help identify factors or medications that may be involved. I encourage you to discuss whether your situation is one where alternatives might be available, such as elevated oral doses of vitamin B12, or ones administered as a sublingual tablet, nasal gel or spray.
Check out the additional discussion at the National Institutes of Health at b.link/pernicious.
DEAR DR. BLONZ: A lady in my office says that she was told the calcium in milk is the wrong kind for our bodies, and is not easily absorbed. Since she is pregnant, I’d like to be sure this is correct, so she’s not ignoring something important. Is there any truth to this? -- M.M., Phoenix, Arizona
DEAR M.M.: No. The idea that the calcium in milk is the “wrong kind” is without merit.
There are many types and dietary sources of calcium. Dairy products represent an excellent and convenient source. One advantage is that the body absorbs a higher percentage of dairy calcium than calcium carbonate, which is a common form of calcium found in dietary supplements.
A key consideration here is that while calcium is essential -- especially for a mother and her developing child -- dairy products are not.
Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.