Written By: N. Lothungbeni Humtsoe | Published : November 1, 2025 7:56 PM IST
Vitamin B12 is an important nutrient that your body requires to make red blood cells, nerves and DNA. This powerful nutrient produces energy to let you go throughout the day, as well as improves brain function and mood. Interestingly, your body does not make vitamin B12 on its own, and the only way to meet your requirement is through foods that are rich in vitamin B12.
If you have been recently experiencing memory issues, confusion and cognitive changes, experts indicate that this could be a sign of vitamin B12 deficiency.
Vitamin B12 deficiency is a medical condition that occurs when your body is not getting enough or not absorbing enough vitamin B12 from the foods that you're consuming. According to Dr O'Donovan, who holds an MBBS and has a huge following on YouTube, vitamin B12 deficiency can occur when you consume too little or too much energy and nutrients, apart from other causes such as gastrointestinal disorders, certain medications, and age-related decline.
He explains, "Vitamin B12 deficiency happens if you aren't eating enough vitamin B12 or your body isn't absorbing the B12 that you're consuming properly. Now, one of the most common causes of vitamin B12 deficiency is in people who don't eat enough foods that naturally have vitamin B12 in them, or they don't eat foods that are fortified with vitamin B12."
"Another reason for not getting enough vitamin B12 is that your body isn't absorbing enough of it. Causes for this could include gastritis, which is inflammation of the stomach lining, lack of hydrochloric acid in your stomach, which is needed for absorption," Dr O'Donovan added, "People who've got something called pernicious anaemia, which is a rare medical condition, can't make enough intrinsic factor, which is the protein that is made by your stomach to help absorb B12. Diseases that affect the digestive system, like Crohn's disease and Celiac disease, can also prevent your body from fully absorbing B12."
"Similarly, people who've had gastrointestinal surgery like gastric bypass, which is a type of weight loss surgery, can also have difficulty absorbing enough vitamin B12. Alcohol use disorder can damage your digestive system and cause a deficiency. Finally, a rare condition that's called Transcobalamin 2 deficiency, which is a rare genetic disorder, impairs the transport of vitamin B12 within the body," he concludes.
Talking about the dangers of vitamin B12 deficiency, in his latest video, the doctor explains that vitamin B12 deficiency can cause a range of different things, including physical, neurological and psychological symptoms.
"Neurological symptoms of vitamin B12 deficiency, which are those affecting the brain, can include numbness or tingling in your hands and feet, vision problems, having a hard time remembering things or getting confused easily or having a difficult time walking or speaking like you usually do," Dr. O'Donovan. "Psychological symptoms of vitamin B12 deficiency can include feeling depressed, feeling irritable, experiencing a change in the way you feel or behave, so as you can see, it's a huge range of potential symptoms that could display if you have a B12 deficiency."
Other symptoms of vitamin B12 deficiency include "feeling very tired or weak, experiencing nausea, vomiting or diarrhoea, not feeling as hungry as usual, and even having weight loss, a sore mouth or tongue or developing yellowish-looking skin."
Older adults, people with certain medical conditions, those taking certain medications and people who avoid or consume less animal products are at risk of vitamin B12 deficiency.
Vitamin B12 deficiency may occur due to a diet lacking in animal products, certain medical conditions, older age, and certain medications.
