If you’ve been feeling foggy, forgetful, or constantly moody and brushing it off as “just stress,” you might want to think again. A Hyderabad-based neurologist, Dr Sudhir Kumar, recently shared a real-life case that proves how what we often dismiss as burnout could actually be a serious health issue hiding in plain sight — a Vitamin B12 deficiency. And the surprising part? It’s way more common than most people think, especially among vegetarians.

Dr Kumar took to X (formerly Twitter) to share the story of a 33-year-old IT professional who came to him after years of forgetfulness, mood swings, and irritability. Despite being young and healthy, these symptoms had started to affect his work performance and relationships. Like many of us, his family chalked it up to work stress. But Dr Kumar suspected there was more to it.

Vegetarian diet and Vitamin B-12 deficiency

On digging deeper, he discovered that the man was a strict vegetarian — a detail that immediately caught his attention. When tests were done, the results were shocking: his active Vitamin B12 level was just 10 pmol/L, while the normal range should be above 70. That’s not just low — it’s severely deficient.

“Vitamin B12 is crucial for brain and nerve function,” Dr Kumar explained. “Deficiency can present with neuropsychiatric symptoms-forgetfulness, irritability, mood changes, depression, or poor concentration, sometimes even without anaemia or obvious nerve damage.” In this case, years of following a vegetarian diet without supplements had quietly drained the man’s B12 reserves, leaving him mentally exhausted and emotionally unstable.

Once diagnosed, the patient was started on intramuscular Vitamin B12 injections and later shifted to a maintenance plan. He was also advised to add dairy products and fortified foods to his diet. Within weeks, his mood started improving. A few months later, his concentration and memory bounced back — so much so that his family said he was “back to his usual self.”

Vitamin B-12 deficiency symptoms

Dr Kumar explained that Vitamin B12 deficiency often disguises itself as stress, particularly in young professionals dealing with high-pressure jobs. Since symptoms like fatigue, brain fog, and mood swings can easily be mistaken for burnout or depression, many people never think to get tested. He emphasised that identifying the deficiency early can completely change a person’s quality of life.


He added that Vitamin B12 deficiency is extremely common in India, particularly among vegetarians and vegans, since the vitamin is mostly found in animal products. The good news? A simple blood test can detect it, and with timely treatment, the damage is completely reversible. So, if your constant stress or fading memory feels harder to explain, the problem might not be in your head — it could be on your plate. Dr Kumar pointed out that ongoing forgetfulness or irritability isn’t always about mental strain; sometimes, it’s your brain’s way of signalling that it needs more Vitamin B12.

How to prevent Vitamin B-12 deficiency?

Most people can prevent vitamin B12 deficiency by including B12-rich foods in their diet, according to the Cleveland Clinic. Animal products like fish, eggs, dairy, poultry, and red meat are natural sources of B12. Fortified foods, such as certain breakfast cereals, plant-based milks, nutritional yeast, and some breads, also provide the vitamin—just check labels for B12 content. Limiting alcohol is also important, as frequent drinking can reduce B12 absorption.