From the Guidelines
Vitamin B12 deficiency and iron deficiency anemia are distinct conditions that can sometimes coexist but have different underlying mechanisms and treatments. The relation between A12 (Vitamin B12) and iron deficiency anemia is that they can coexist, particularly in conditions like inflammatory bowel disease (IBD) where malabsorption of multiple nutrients can occur 1. In IBD, iron deficiency is estimated to affect a third of patients with active disease, while vitamin B12 and folate deficiency may also contribute to the anemic state 1.
Key points to consider in the management of iron deficiency anemia in the context of potential vitamin B12 deficiency include:
- The absorption of oral iron may be impaired by systemic inflammatory processes, small bowel involvement, and/or previous surgery, which may favor intravenous iron replacement therapy (IRT) in some cases 1.
- Current guidelines suggest that oral IRT in patients with IBD should contain no more than 100 mg elemental iron a day, and intravenous iron is indicated for those who are intolerant of oral iron and have moderate to severe iron deficiency anemia (Hb <100 g/L) 1.
- Optimizing nutritional and pharmacological management to bring active IBD into remission is expected to help improve iron deficiency anemia metrics and response to iron therapy 1.
- Diagnosing and treating vitamin B12 deficiency requires specific consideration, including B12 supplementation, which may be oral or injectable depending on the patient's absorption status.
In clinical practice, it's crucial to correctly diagnose which deficiency is present through appropriate blood tests, including complete blood count, peripheral smear, B12 levels, folate levels, iron studies, and sometimes methylmalonic acid or homocysteine levels for B12 deficiency confirmation. Addressing both vitamin B12 and iron deficiencies specifically, when present, is essential for improving patient outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Relation of A12 and Iron Deficiency Anemia
- The relationship between iron deficiency and vitamin B12 (A12) has been recognized for several decades, with combined deficiency being important in clinical practice due to its relationship with malabsorption syndromes 2.
- A study found that treatment of iron deficiency anemia with pharmacological iron in young adult women increased serum folate and vitamin B12 levels, suggesting that iron deficiency could affect many metabolic pathways, including vitamin B12 and folate 2.
- Vitamin B12 deficiency is a common cause of megaloblastic anemia, and screening may be warranted in patients with risk factors such as gastric or small intestine resections, inflammatory bowel disease, or use of certain medications 3.
- Iron, folic acid, and vitamin B12 deficiencies are common problems in consultations of general internal medicine, and can cause different symptoms that can be non-specific 4.
- A study in adolescents from Venezuela found that the prevalence of anemia was associated with folic acid deficiency rather than iron deficiency, and that simultaneous iron and folic acid deficiencies affected a significant proportion of anemic cases 5.
- Another study in community-dwelling elderly in Turkey found that the prevalence of anemia was 7.3%, and that deficiencies of iron, vitamin B12, and folic acid were also high in this population 6.
Key Findings
- Iron deficiency can affect vitamin B12 levels, and treatment of iron deficiency anemia can increase serum vitamin B12 levels 2.
- Vitamin B12 deficiency is a common cause of megaloblastic anemia, and screening may be warranted in patients with risk factors 3.
- Iron, folic acid, and vitamin B12 deficiencies are common problems in general internal medicine, and can cause different symptoms 4.
- The prevalence of anemia and nutritional deficiencies can vary depending on the population being studied, with different factors contributing to anemia in different age groups and populations 5, 6.
Biochemical Parameters
- Treatment of iron deficiency anemia with pharmacological iron can increase serum folate and vitamin B12 levels, as well as other biochemical parameters such as glucose, uric acid, total cholesterol, HDL cholesterol, and bilirubin 2.
- Vitamin B12 deficiency can be confirmed by measurement of serum methylmalonic acid, and oral administration of high-dose vitamin B12 can be effective in correcting anemia and neurologic symptoms 3.