Vitamin B12 is essential for energy, nerve health, and DNA production. Despite being present in many foods, deficiency is common—especially in people over 60—due to poor absorption or diet. Symptoms can range from fatigue and weakness to mood changes or memory issues. It’s important to catch and treat B12 deficiency early to avoid long-term damage.
Vitamin B12 deficiency is determined as follows:
What happens when your vitamin B12 is low?
1. Fatigue
Feeling tired all the time? It could be due to a vitamin B12 deficiency. Your body needs B12 to make healthy red blood cells that carry oxygen. Without enough B12, you may develop megaloblastic anemia — a condition where your red blood cells are too large and not functioning properly, leading to fatigue and low energy.
2. Pale or Yellow Skin
Vitamin B12 deficiency can lead to pale or yellowish skin. This happens because the body lacks enough healthy red blood cells, similar to iron deficiency anemia. In some cases, it may also cause jaundice, where the skin and eyes turn yellow due to a buildup of bilirubin.
3. Headaches
Headaches, especially migraines, are a common sign of vitamin B12 deficiency. A 2019 study found that people with migraines had significantly lower B12 levels. Those with higher B12 were up to 80% less likely to suffer from migraines. Research is ongoing to see if B12 supplements can help reduce migraine symptoms.
4. Depressive Symptoms
Low vitamin B12 levels are linked to a higher risk of depression. This may be due to increased homocysteine, which can cause oxidative stress and cell damage, contributing to depressive symptoms. A 2020 study found that kids with depression had lower B12 and higher homocysteine levels.
5. Digestive problems
Not getting enough vitamin B12 can lead to a range of digestive troubles, including nausea, diarrhea, constipation, bloating, and excess gas.
These symptoms aren’t limited to adults—they can also show up in children.
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.