Vitamin B12 is essential in brain development in children and in maintaining a healthy nervous system and red blood cells. Animal products, including meat, fish, dairy and eggs, are the only natural sources of B12. Lacto-ovo vegetarians can obtain B12 through eggs and dairy but vegans must use supplements or fortified foods. B12 deficiencies are far more prevalent of vegetarians and especially vegans.
Low blood levels of Vitamin B12 is linked with neurological disorders and memory loss. In a recent study of geriatric patients, Vitamin B12 deficiency was more prevalent in elderly males (56.67%) and was most commonly associated with increased severity of behavioral disturbances. Memory loss was present in 16 (84.2%) patients with severe Vitamin B12 deficiency (<150pmol/L). B12 deficiency can also lead to Pernicious anemia.