They tell us that Australia has an 'aging population problem' and an associated ‘dementia epidemic’, with Alzheimers Disease the leading diagnosis. But everything that looks like Alzheimers is not Alzheimers. Vitamin B12 deficiency causes an easily treatable and reversible form of dementia which has been increasingly overlooked since the 1980s, although it was discovered in 1900 and the cure found in 1926, earning Minot and Murphy a Nobel Prize. Previously it was core medical practitioner knowledge that the ability to absorb Vitamin B12 via the gut diminishes with age and may cause dementia. [See appendix at end of article: “Useful reference documents on age, Vitamin B12 and dementia.”] This failure to absorb Vitamin B12 orally can be compensated by B12 injections and or by megadose lozenges or drops absorbed under the tongue. It used to be wide practice to give B12 injections to people over 60 monthly in Australia and many other countries, but for a variety of reasons this went out of fashion. The problem is not confined to the elderly. Children breastfeeding from mothers low in B12 have a high risk of neurological damage. Vitamin B12 cannot be supplied from vegan diets. [2a] There is also quite a large group of people of all ages, including children, who develop auto-immune pernicious anaemia (due to loss of the 'intrinsic factor') , which can and will cause brain injury, psychiatric problems, dementia, paralysis and death if untreated. However Australian, British and United States medical teaching, diagnostic and treatment guidelines are very problematic with regard to B12 deficiencies. So problematic that there is now a huge international movement where sufferers of pernicious anaemia teach each other about diagnosis and treatment, and where to access different forms of the vitamin, while they try to inform the medical profession.