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.