Vitamin B12 plays an important role in red blood cell production, nerve function and several processes that support the brain and nervous system. When the body doesn't get enough of this vitamin, symptoms can develop gradually and may sometimes be mistaken for ordinary tiredness or stress.

A doctor has highlighted five possible warning signs that shouldn't be ignored, particularly when several of them occur together.

1. Your Tongue Becomes Red, Smooth or Painful

One possible sign of B12 deficiency is a condition called atrophic glossitis.

The tongue may appear unusually smooth, shiny or red and can sometimes feel swollen or painful. The tiny structures normally present on the surface of the tongue can become less prominent.

If these changes persist, it's worth discussing them with a healthcare professional rather than assuming they're simply due to a minor mouth problem.

2. You Feel Extremely Tired

Unexplained fatigue is another possible sign.

Vitamin B12 is involved in the production of healthy red blood cells. A significant deficiency can contribute to megaloblastic anemia, which can reduce the amount of oxygen delivered to tissues.

As a result, some people may experience tiredness, weakness, dizziness, breathlessness or reduced exercise tolerance.

However, fatigue has many possible causes, so it cannot by itself confirm a B12 deficiency.

3. Tingling or Numbness in Your Hands and Feet

B12 is important for maintaining healthy nerves. A prolonged deficiency can affect the nervous system and lead to symptoms such as tingling, numbness, burning sensations or reduced sensitivity.

These symptoms may initially appear in the feet or hands and can gradually become more noticeable.

Importantly, nerve-related symptoms can sometimes occur even when a person's blood count does not show obvious anemia.

4. Brain Fog and Memory Problems

Some people with B12 deficiency may experience changes in cognitive function.

Possible symptoms include difficulty concentrating, forgetfulness, slower thinking, confusion or changes in mood.

These symptoms can have many other causes, including lack of sleep, stress, medication effects and other medical conditions. Persistent or unexplained cognitive changes therefore deserve proper medical evaluation.

5. Problems With Balance or Walking

A prolonged B12 deficiency can affect certain nerve pathways involved in sensing the position of your body.

This can lead to balance problems, stumbling or difficulty walking, particularly in situations where visibility is poor, such as walking in the dark.

Because nerve damage can become more difficult to reverse if a deficiency remains untreated for a long time, persistent neurological symptoms should not be ignored.

Who May Be at Risk of B12 Deficiency?

B12 deficiency can occur for several reasons. People who consume little or no animal-derived food may have a higher risk because vitamin B12 naturally occurs mainly in animal foods.

Older adults and people with certain digestive conditions or problems absorbing nutrients can also be at increased risk. Some medications may affect B12 absorption as well.

Should You Take B12 Supplements on Your Own?

Not necessarily. These symptoms do not automatically mean that you have a B12 deficiency.

If you have persistent fatigue, numbness, balance problems or other symptoms, speak with a doctor. They can determine whether testing is appropriate and identify the underlying cause.

If a deficiency is confirmed, your doctor can recommend the appropriate dietary changes or supplementation based on its cause and severity.

Don't Ignore Persistent Symptoms

Vitamin B12 deficiency can affect both the blood and nervous system, and some symptoms can become more serious when the deficiency continues for a long time.