The hidden signs of Vitamin B12 deficiency that mimic depression and ageing

If you often wake up tired, lose focus at work, or feel unusually low, your body might be missing something simple - Vitamin B12. This essential nutrient keeps your brain sharp, nerves healthy, and energy levels stable. Yet doctors say deficiency is far more common than most people realise, especially among vegetarians and older adults. Take a look

Vitamin B12 deficiency and how it affects energy and mood

If you often feel exhausted, forget simple things, or find it hard to concentrate, it may not just be stress. Doctors call Vitamin B12 deficiency one of the most overlooked health problems today because it quietly affects the brain, mood, and nerves.




According to the National Institutes of Health (NIH), Vitamin B12 is needed to make red blood cells, protect nerves, and produce DNA. When levels fall, the body struggles to carry oxygen efficiently, leading to weakness, fatigue, and cognitive changes.

Why Indians are more prone to Vitamin B12 deficiency

Vitamin B12 is found mainly in animal-based foods such as eggs, milk, fish, and meat. This makes vegetarians and vegans more likely to have low levels.

A 2020 study by AIIMS found that nearly half of Indians tested had insufficient Vitamin B12, especially urban adults who eat little dairy or animal protein. Certain medicines, including metformin for diabetes and acid-reducing drugs, can further lower absorption.

Ageing also increases risk because stomach acid production decreases with time, making it harder to release B12 from food.

Common Vitamin B12 deficiency symptoms that often go unnoticed

Vitamin B12 deficiency develops slowly, so symptoms often go unnoticed or are mistaken for other issues such as anxiety, depression, or early ageing.

Common warning signs include:

• Persistent fatigue or weakness
• Numbness or tingling in hands and feet
• Poor concentration or memory lapses
• Mood swings or irritability
• Pale skin or shortness of breath
• Balance or coordination problems
• Frequent infections or slow-healing wounds
• Brittle nails or hair loss due to nutrient deficiencies

If untreated, severe deficiency can cause permanent nerve damage and cognitive decline.

Vitamin B12 and brain health: How low levels affect mood and memory

Vitamin B12 helps the brain produce serotonin, the chemical that regulates mood and sleep. Low levels can lead to low mood, brain fog, and anxiety-like symptoms.

A review in the Journal of Psychopharmacology found that treating Vitamin B12 deficiency improved mood and reduced depressive symptoms in several patient groups. Another Harvard Health analysis noted that older adults with low Vitamin B12 levels were more likely to experience memory and thinking problems.

The gut and Vitamin B12 absorption: How digestion affects your levels

Vitamin B12 absorption starts in the stomach, where it binds to a protein called intrinsic factor before moving into the intestine. Conditions such as gastritis, celiac disease, Crohn’s disease, or long-term antibiotic use can block this process.

Prolonged antibiotic use also disrupts gut bacteria that help produce certain B vitamins. For this reason, doctors often test both Vitamin B12 and folate levels in people with unexplained fatigue or tingling sensations.

Vitamin B12 food sources and safe supplementation options

Treatment depends on how low your levels are. Mild cases can usually be corrected with diet, while severe ones may need supplements or injections.



For vegetarians and vegans, fortified foods are the best option. The ICMR–NIN 2020 guidelines recommend 2.4 µg of Vitamin B12 per day for adults.

Supplements are safe when prescribed by a doctor. Because Vitamin B12 is water-soluble, any excess is passed out in urine, making toxicity very rare.

When to get tested for Vitamin B12 deficiency

If you have persistent tiredness, tingling, or memory problems, your doctor may suggest a serum Vitamin B12 test, along with homocysteine and methylmalonic acid (MMA) tests, which give a more accurate picture of your levels.

Early detection is essential. Long-term deficiency can cause nerve and brain damage that may not fully reverse even after treatment.

The takeaway


Vitamin B12 deficiency is often overlooked but easy to correct. Increasing intake of B12-rich foods, supporting gut health, and regularly monitoring levels can prevent symptoms like fatigue, mood changes, and nerve problems. Sometimes, feelings of stress or aging are actually your body signaling a need for this essential vitamin, making awareness and timely action important.