June 6, 2014
Watch B12 Levels If You Take Metformin or Antacids
The Joslin Diabetes Center apparently has some doubts about metformin causing vitamin B12 deficiency. Studies have shown that long-term metformin use causes about 30 percent of patients to develop B12 deficiency. Yet, Joslin believes that food is the answer and waits until the last two paragraphs to discuss to problems that vitamin B12 deficiency can cause. They even try to minimize the deficiency and go to great lengths and quote the American Diabetes Association to emphasize their point.
The unidentified blog author says, “But just because these people taking metformin had lower levels of B12 in their bloodstream doesn’t necessarily mean the B12 that’s there isn’t getting the job done. New measurements of B12 activity have indicated that although metformin does seem to reduce blood levels of B12, this may not reduce the vitamin’s effectiveness in carrying out it its functions in the body. When B12 doesn’t work the way it’s supposed to, levels of something called total plasma homocysteine (tHcy) go up. But newer studies looking at the levels of tHcy in people who take metformin have found that they have not been elevated.”
“According to an article published this year in Diabetes Care, “low serum B12 alone without disturbances in the metabolic markers has no diagnostic value.” From a practical standpoint, this means that if a B12 deficiency is suspected from a serum B12 test, further testing should be undertaken before assuming the patient is B12 deficient.”
Vitamin B12 is one of the B vitamins that are needed for the healthy development of blood cells, DNA, and the nervous system. B12 is a water soluble vitamin and can possibly be stored in the liver as long as one year. Vitamin B12 is obtained from most animal products, fish, and especially animal liver. People eating a vegan diet will need to consume a B12 supplement, B12 enriched tofu, or yeast to obtain adequate levels of vitamin B12.
This is important for people with type 2 diabetes and on metformin. B12 deficiency can lead to megaloblastic anemia, a type of anemia in which the red blood cells are significantly larger than normal. People with mild B12 deficiency may feel weak and tired, bleed easily, experience tingling in the hands and feet (neuropathy), and swelling of the tongue. People that experience severe B12 deficiency can have serious effects such as memory loss, delusions, lost of taste and smell.
In the last paragraph, the author finally admits that metformin contributes to serum B12 deficiency by preventing its transfer into the blood through a calcium dependent membrane. This leads to decreased absorption. For vitamin B12 to be absorbed into the blood stream, it needs an acid environment in the stomach.
As people get older and have the need to take acid reducing medications, such as antacids or proton pump inhibitors, they have the increase in the likelihood that they will suffer from a B12 deficiency. It is also possible for this to happen in certain gastrointestinal disorders such as atrophic gastritis, Crohns disease, and surgical reduction of the stomach.
I admit I do not understand doctors that fail to test for B12 deficiency properly and just tell people to eat more meats. Few consider the person's age or ask what medications the person is taking that might be a cause for B12 deficiency.
This article also helps justify B12 testing. Early Alzheimer's can be confused for B12 deficiency. Please read the post linked.