Higher than normal levels of Vitamin B12 may indicate cancer risk

Vitamin B12 (cobalamin [Cbl]) is essential for maintaining healthy bodily function but higher than normal levels (reference range 200-600 pmol/L) may indicate that a patient is at risk of developing certain cancers, according to a study published November 18 in the Journal of the National Cancer Institute. Previous studies had suggested an association between high Cbl levels and specific cancers.

To assess the association between high Cbl levels and risk of cancer of any type, Johan Arendt, BSc, of the Department of Clinical Epidemiology and the Department of Clinical Biochemistry of Aarhus University Hospital in Denmark, and colleagues used Danish Medical registries to review the records of 333,667 patients without cancer who had been referred for Cbl testing and to estimate the incidence of cancer in this population from 1998 to 2010.

The researchers excluded patients who had a cancer diagnosis before the date of plasma measurement and those who were receiving Cbl therapy. They found that the risk of cancer overall increased with higher Cbl levels, especially during the first year after measurement and for those with levels > 800pmol/L. They also found that after five years of follow-up, the risk for hematological and alcohol and smoking-related cancers remained high for those with levels > 800pmol/L.

The authors conclude that "…high plasma Cbl levels increased the risk of subsequently diagnosed cancer, mostly within the first year of follow-up." However, Arendt et al. note that high plasma Cbl levels are probably not related to normal Vitamin B12 intake because consumption of Cbl containing foods or supplements do not increase plasma Cbl levels substantially. Rather, high Cbl levels may result from some unknown malignant process.

What is vitamin B12 deficiency anemia?

Having vitamin B12 deficiency means that your body does not have enough of this vitamin. You need B12 to make red blood cells camera, which carry oxygen through your body. Not having enough B12 can lead to anemia, which means your body does not have enough red blood cells to do the job. This can make you feel weak and tired.
What causes vitamin B12 deficiency anemia?

Most people get more than enough B12 from eating meat, eggs, milk, and cheese. Normally, the vitamin is absorbed by your digestive system-your stomach and intestines. Vitamin B12 deficiency anemia usually happens when the digestive system is not able to absorb the vitamin. This can happen if:

You have pernicious anemia. In this anemia, your body destroys the cells in your stomach that help you absorb vitamin B12.
You have had surgery to remove part of the stomach or the last part of your small intestine, called the ileum camera. This includes some types of surgery used to help very overweight people lose weight.