Can Vitamin B12 Deficiency Be a Sign of Cancer?

Vitamin B12 is essential for healthy nerve function, red blood cell production and DNA synthesis. A deficiency in this vitamin can lead to symptoms such as fatigue, weakness, numbness or tingling in the hands and feet, and cognitive difficulties. While vitamin B12 deficiency is often caused by dietary insufficiency or absorption problems, in some cases it may be linked to underlying medical conditions, including certain cancers.

How Cancer Can Cause Vitamin B12 Deficiency

Certain cancers can interfere with vitamin B12 absorption or increase its demand, leading to deficiency. For example, stomach cancer or cancers affecting the gastrointestinal tract may damage the cells responsible for producing intrinsic factor, a protein necessary for B12 absorption in the intestines. Without intrinsic factor, vitamin B12 cannot be properly absorbed, resulting in deficiency.

Some blood cancers, such as leukemia or lymphoma, may also disrupt normal blood cell production and vitamin metabolism, contributing to low B12 levels. Additionally, cancer treatments like chemotherapy can affect nutrient absorption or cause increased nutritional needs.

When to Seek Medical Advice

If vitamin B12 deficiency is diagnosed without an obvious cause, further investigation may be necessary to rule out serious conditions including cancer. Persistent or unexplained B12 deficiency should prompt consultation with a healthcare professional for appropriate testing and diagnosis.

Summary

Vitamin B12 deficiency can sometimes be a sign of underlying cancer, particularly those affecting the stomach or blood. While more common causes exist, unexplained deficiency warrants medical evaluation to exclude serious conditions.