People at risk of a B12 deficiency include: the elderly; those who've had surgery that removes the part of the bowel that absorbs B12; people on the drug metformin for diabetes; people following a strict vegetarian or vegan diet; those taking long-term antacid drugs for heartburn.
Unfortunately, symptoms of a vitamin B12 deficiency can take years to show up, and diagnosing it can be complex. A B12 deficiency can sometimes be mistaken for a folate deficiency. Low levels of B12 cause your folate levels to drop. However, if you have a B12 deficiency, correcting low folate levels may simply mask the deficiency and fail to fix the underlying problem.
Here are 9 signs and symptoms of a true vitamin B12 deficiency:
1. Pale or Jaundiced Skin
People with a B12 deficiency often look pale or have a slight yellow tinge to the skin and whites of the eyes, a condition known as jaundice. This happens when a lack of B12 causes problems with your body's red blood cell production. Vitamin B12 plays an essential role in the production of the DNA needed to make red blood cells. Without it, the instructions for building the cells are incomplete, and cells are unable to divide.
This causes a type of anemia called megaloblastic anemia, in which the red blood cells produced in your bone marrow are large and fragile. These red blood cells are too large to pass out of your bone marrow and into your circulation. Therefore, you don't have as many red blood cells circulating around your body, and your skin can appear pale in color. The fragility of these cells also means that many of them break down, causing an excess of bilirubin. Bilirubin is a slightly red or brown-colored substance, which is produced by the liver when it breaks down old blood cells. Large amounts of bilirubin are what give your skin and eyes a yellow tinge.