Certain groups face elevated risk of B12 deficiency and should discuss testing with their healthcare provider: Individuals following vegan or strict vegetarian diets without adequate supplementation Older adults (particularly those over 60 years), due to reduced gastric acid production People with gastrointestinal conditions including Crohn's disease, coeliac disease, or those who have undergone gastric or ileal surgery Long-term users of medications affecting B12 absorption, such as metformin (MHRA advises monitoring B12 levels), PPIs, or H2-receptor antagonists Individuals with pernicious anaemia or family history of this autoimmune condition People with exposure to nitrous oxide (recreational or occupational), which can cause functional B12 deficiency Diagnostic testing typically involves serum B12 measurement , though this may not always reflect tissue stores accurately
You need a valid prescription from a qualified healthcare professional
He reviewed my records, tests, and my symptoms
doi: 10.3389/fnut.2025.1679494 Received 04 August 2025 Revised 19 October 2025 Accepted 25 December 2025 Published 22 January 2026 Volume 12 - 2025 Edited by Manuela Machado, Escola Superior de Biotecnologia - Universidade Catlica Portuguesa, Portugal Reviewed by Ivan oa, University of Rijeka, Croatia Moumita Saha, Yale University, United States Updates Copyright 2026 Chang, Lin, Renn, Liu, Yen, Liao, Tikhonova, Amstislavskaya, Singh and Chen
