MM a 46 year old man with recurring episodes of chest pain and syncope requiring emergency room evaluation on 5 occasions over the previous year
Dietary factors represent a significant risk category: Vegans and strict vegetarians, as B12 is naturally found almost exclusively in animal products Individuals with poor nutritional intake due to socioeconomic factors or eating disorders Elderly people with reduced dietary variety Pregnant and breastfeeding women following vegan diets (increased requirements) Gastrointestinal conditions that impair B12 absorption include: Pernicious anaemia (an autoimmune condition affecting intrinsic factor production) Crohn's disease, particularly affecting the terminal ileum Coeliac disease Previous gastric or ileal surgery (including bariatric procedures) Chronic atrophic gastritis Small intestinal bacterial overgrowth Pancreatic insufficiency (a less common cause) Medication-related risks include: Metformin therapy for type 2 diabetes (MHRA advises monitoring B12 levels) Long-term use of proton pump inhibitors (PPIs) or H2-receptor antagonists (consider testing if symptomatic or with additional risk factors) Other at-risk groups include: Older adults (over 60 years), due to reduced gastric acid production Individuals with autoimmune conditions (thyroid disease, vitiligo, Addison's disease) People with HIV infection Those with chronic alcohol misuse Recreational or occupational nitrous oxide users (causes acute functional B12 deficiency) Infants born to B12-deficient mothers, particularly if exclusively breastfed The MHRA specifically highlights the importance of monitoring B12 levels in patients on long-term metformin
HiranoAUmenoJOkamotoYShibataHOguraYMoriyamaTet al
And finally, the most interesting piece: All of these carnosol effects were nearly similar to those observed with fluoxetine
Lai ZW, Hanczko R, Bonilla E, et al
