“Some of these symptoms can also happen in people who have a vitamin B12 deficiency but have not developed anaemia,” it adds.
The deficiency, if left untreated, can cause severe and irreversible damage, especially to the brain and nervous system. It can also increase the risk of cardiovascular disease.
Good sources of vitamin B12 include meat, fish, milk, cheese and eggs. If you eat meat, fish or dairy foods, you should be able to get enough vitamin B12 from your diet, according to the NHS.
You can also look out for vegan and vegetarian foods that are fortified with vitamin B12, such as some plant milks and breakfast cereals.