What is a common symptom of B12 deficiency?

A common symptom of vitamin B12 deficiency is fatigue. This occurs because vitamin B12 is essential for the production of red blood cells, which transport oxygen throughout the body. When there is a deficiency, the production of healthy red blood cells is impaired, leading to anemia, which can cause feelings of tiredness or weakness as the body's tissues do not receive adequate oxygen.

Fatigue is often one of the first symptoms noticed in people with B12 deficiency, and it can be accompanied by other signs such as pallor, dizziness, and difficulty concentrating. It's important to recognize these symptoms early, as prolonged deficiency can lead to more severe neurological issues and other complications.

The other options presented—weight gain, increased appetite, and shortness of breath—do not typically correlate with B12 deficiency and are not recognized as common symptoms associated with it. Understanding the typical manifestations of vitamin deficiencies can help in early diagnosis and treatment, leading to better health outcomes.