These conditions can often be diagnosed based on your symptoms and the results of a blood test.
There are several risk factors for vitamin B12 deficiency anaemia including a family history of the disease, autoimmune diseases, including type 1 diabetes and Crohn’s disease.
If you eat meat, fish or dairy foods, you should be able to get enough vitamin B12 from your diet, and are unlikely to need to take supplements.
“However, older adults, vegetarians, vegans and people who have conditions that affect their ability to absorb vitamin B12 from foods might benefit from the use of oral supplements”, according to the Mayo Clinic.