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Pernicious Anemia

A type of anemia (low red blood cell count) caused by the body's inability to absorb vitamin B12.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

Pernicious Anemia

Pernicious anemia (per-NISH-us uh-NEE-me-uh) is a condition in which the body can't make enough healthy red blood cells because it doesn't have enough vitamin B12.

Vitamin B12 is a nutrient found in some foods. The body needs this nutrient to make healthy red blood cells and to keep its nervous system working properly.

People who have pernicious anemia can't absorb enough vitamin B12 from food. This is because they lack intrinsic (in-TRIN-sik) factor, a protein made in the stomach. A lack of this protein leads to vitamin B12 deficiency.

Other conditions and factors also can cause vitamin B12 deficiency. Examples include infections, surgery, medicines, and diet. Technically, the term "pernicious anemia" refers to vitamin B12 deficiency due to a lack of intrinsic factor. Often though, vitamin B12 deficiency due to other causes also is called pernicious anemia.

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What works? Research summarized

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Bibliographic details: Yao XJ, Liu CX.  Erythropoietin for cancer-related malignant anemia: a meta-analysis. Chinese Journal of Evidence-Based Medicine 2010; 10(7): 842-847

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Summaries for consumers

No evidence of the efficacy of vitamin B12 supplementation for cognitive function

Vitamin B12 is essential for maintaining normal function of the nervous system, but the relationship between vitamin B12 and cognitive function is not fully understood. From the three studies involving people with dementia or cognitive impairment and low blood levels of vitamin B12 eligible for inclusion in this review there was no statistically significant effect of vitamin B12 supplementation on cognition. The variety of measurement scales used to assess outcomes and uncertainty about diagnostic criteria for vitamin B12 deficiency create difficulties in pooling the results of trials.

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More about Pernicious Anemia

Photo of an adult

Also called: Pernicious Anaemia, Cobalamin deficiency, Combined systems disease

See Also: Vitamin B12

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