6. Difficulty Concentrating and Mental Impairment
Vitamin B12 deficiency can lead to problems with focus, memory, and overall mental clarity due to its role in brain and nerve health. Many older adults with low B12 levels experience mental decline, but studies show that proper B12 supplementation can improve these cognitive issues over time.

7. Mouth and Tongue Pain
A B12 deficiency can cause glossitis—an inflamed, red, and painful tongue. It may also lead to mouth sores (stomatitis). These symptoms can happen even without anemia and may be early signs of low B12.

8. Tingling in Hands and Feet (Paresthesia)
A common sign of B12 deficiency is a pins-and-needles feeling in the hands or feet. This can be confused with diabetic nerve damage. People with diabetes who take metformin are especially at risk, as the drug may lower B12 levels.

9. Other Signs of B12 Deficiency
B12 deficiency may also cause muscle cramps, weakness, balance problems, erectile dysfunction, and even vision disturbances, mainly due to its impact on nerves and circulation.

How is B12 deficiency detected and treated?

Vitamin B12 deficiency can be tricky to spot, since its symptoms often overlap with other conditions. That means it can sometimes be overlooked or misdiagnosed.

If you’re noticing any of the symptoms mentioned earlier, it’s a good idea to bring them up with your doctor or a healthcare provider.

This is particularly important if you:

• follow a restrictive eating pattern, such as a vegan diet
• are 60 or older
• are pregnant or breastfeeding
• have a health condition that affects B12 levels
• take medications that reduce B12, like metformin or proton pump inhibitors

Along with reviewing your health history…

What is the main cause of vitamin B12 deficiency?

B12 deficiency often happens due to a lack of animal-based foods like meat, fish, or eggs—making it more common in vegans and vegetarians. But it can also result from health issues (like anemia or digestive disorders) or medications that block B12 absorption.

Bottom Line

Vitamin B12 deficiency can lead to fatigue, headaches, depression, pale skin, cognitive issues, and mouth pain. Since these symptoms are common to other conditions, B12 deficiency can be hard to spot. If you notice any of them, see a doctor for proper testing and treatment.