Vitamin B12 (Methylcobalamin)

Helicobacter pylori infection, atrophic gastritis, and disabling dementia: the Japan Public Health Center-based Prospective Study.

Matsunaga T, Yamagishi K, Iso H, Yasuda N, Inoue M, Tsugane S · Environmental health and preventive medicine · 2026 · n=817

A meta-analysis reported a positive association between Helicobacter pylori (H. pylori) infection and dementia incidence. H. pylori infection leads to atrophic gastritis (AG) and affects the absorption of nutrients needed for nerve growth, such as vitamin B12 and folate. We aimed to clarify the associations of H. pylori IgG titer, AG, and their combination with disabling dementia incidence and to examine the interaction with vitamin B12 and folate. Anti-H. pylori immunoglobulin G (IgG) titer and pepsinogen levels were measured in 6,817 participants in 1993 (40-69 years), and the incidence of disabling dementia was followed during a median follow-up of 11.0 years. Associations of anti-H. pylori IgG titer, AG, and their combination with disabling dementia were examined using a multivariable-adjusted Cox proportional hazard model, with stratified analyses by dietary intake of vitamin B12 and folate. 1,325 (19.4%) developed disabling dementia during the follow-up period from 2006 to 2016

Mendelian randomization analysis of the association between vitamin B12 deficiency anaemia and the risk of developing lung disease.

Wang Y, Liu N, Wang T, Liu Y, Yin H, Qu Y · Scientific reports · 2025

The causal relationship between vitamin B12 deficiency anaemia and the risk of developing lung diseases remains unclear. This study aimed to clarify that relationship using Mendelian randomization (MR) with Bayesian weighting, focusing on pulmonary fibrosis (PF), idiopathic PF (IPF), eosinophilic asthma (EA), squamous cell lung cancer (LUSC), chronic obstructive pulmonary disease (COPD), and pulmonary embolism (PE). We analysed genome-wide association study (GWAS) data, applied five MR models with Bayesian methods to assess causality, and validated the results via sensitivity analysis. The MVMR method explores whether vitamin B12-deficient anaemia affects the pathogenesis of IPF independently of BMI. SMR was used to explore IPF-related pathogenesis, whereas a meta-analysis was used to consolidate LUSC MR findings across ethnicities. IVW analysis revealed a positive causal link between vitamin B12 deficiency anaemia status and the risk of developing PF [OR (95% CI) = 1.161

Associations between Diet and Cognitive Function in Stroke Survivors: A Systematic Review and Meta-analysis.

Amanat S, Dordevic AL, Brodtmann A, Cardoso BR · Advances in nutrition (Bethesda, Md.) · 2025

Poststroke cognitive decline is a major form of disability in stroke survivors. Although dietary interventions have shown potential in improving cognitive outcomes in stroke-free populations, their effects on stroke survivors remain unclear. This review aimed to evaluate associations between diet and cognitive function in stroke survivors. MEDLINE, Embase, Scopus, and CINHAL were searched for studies from inception to 16 December, 2024. Eligible articles were observational and interventional studies on adult stroke survivors that evaluated the association/effect of any nutritional exposure/intervention on cognitive performance and dementia risk. Studies were excluded when an intervention was combined with nonnutritional treatment. Random-effects meta-analysis was used for similar randomized clinical trials. This review included 20 clinical trials and 14 observational studies assessing the intake of energy and proteins and a variety of single nutrients, as well as dietary patterns, sing

Efficacy of B-vitamins and vitamin D therapy in improving depressive and anxiety disorders: a systematic review of randomized controlled trials.

Borges-Vieira JG, Cardoso CKS · Nutritional neuroscience · 2023 · n=256

This systematic review aimed to evaluate the efficacy of B vitamins and vitamin D therapy in improving the standard treatment of depression and anxiety disorders. We also aimed to gather the evidence supporting the recommendations for supplementation in clinical practice. Performed between March 2020 and September 2021, the main inclusion criteria were randomized controlled trials (RCTs), with patients ≥ 18 years old, both sexes, fulfilling target diagnoses of major depressive disorder (MDD), generalized anxiety disorder (GAD), or mild to severe depressive and anxiety symptoms. In addition, the RCTs were included if the scales to assess the severity of the symptoms were standardized rating scales in psychiatric. Trials that reported diagnoses of schizophrenia, perinatal depression, bipolar depression, sleep disorders, eating disorders, cancer, and multiple sclerosis in association with any of the mentioned diagnoses were excluded. We identified 20 RCTs that match

Health outcomes associated with vegetarian diets: An umbrella review of systematic reviews and meta-analyses.

Oussalah A, Levy J, Berthezène C, Alpers DH, Guéant JL · Clinical nutrition (Edinburgh, Scotland) · 2020

Several meta-analyses evaluated the association between vegetarian diets and health outcomes. To integrate the large amount of the available evidence, we performed an umbrella review of published meta-analyses that investigated the association between vegetarian diets and health outcomes. We performed an umbrella review of the evidence across meta-analyses of observational and interventional studies. PubMed, Embase, Cochrane Database of Systematic Reviews, and ISI Web of Knowledge. Additional articles were retrieved from primary search references. Meta-analyses of observational or interventional studies that assessed at least one health outcome in association with vegetarian diets. We estimated pooled effect sizes (ESs) using four different random-effect models: DerSimonian and Laird, maximum likelihood, empirical Bayes, and restricted maximum likelihood. We assessed heterogeneity using I2 statistics and publication bias using funnel plots, radial plots, normal Q-Q plots, and the Rose

The impact of essential fatty acid, B vitamins, vitamin C, magnesium and zinc supplementation on stress levels in women: a systematic review.

McCabe D, Lisy K, Lockwood C, Colbeck M · JBI database of systematic reviews and implementation reports · 2017

Women juggling multiple roles in our complex society are increasingly experiencing psychological stress. Dietary supplementation to manage stress is widespread despite limited supporting evidence. A systematic review of the available literature was undertaken to investigate the efficacy of specific dietary supplements in managing female stress and anxiety. To identify the impact of essential fatty acids (EFAs), B vitamins, vitamin C, magnesium and/or zinc, consumed as dietary supplements to the daily diet, on female stress and anxiety levels. Women aged 18 years and over, who had participated in a study where stress and/or anxiety were assessed. Dietary supplementation with EFAs, B vitamins, vitamin C, magnesium and/or zinc. Supplements, either alone or combined, were compared with either no intervention or placebo. Randomized controlled and pseudo-randomized trials were included. Stress and anxiety were assessed using self-report or physiological outcome measures. Published and

AGA Clinical Practice Update on Diet and Nutritional Therapies in Patients With Inflammatory Bowel Disease: Expert Review.

Hashash JG, Elkins J, Lewis JD, Binion DG · Gastroenterology · 2024

Diet plays a critical role in human health, but especially for patients with inflammatory bowel disease (IBD). Guidance about diet for patients with IBD are often controversial and a source of uncertainty for many physicians and patients. The role of diet has been investigated as a risk factor for IBD etiopathogenesis and as a therapy for active disease. Dietary restrictions, along with the clinical complications of IBD, can result in malnutrition, an underrecognized condition among this patient population. The aim of this American Gastroenterological Association (AGA) Clinical Practice Update (CPU) is to provide best practice advice statements, primarily to clinical gastroenterologists, covering the topics of diet and nutritional therapies in the management of IBD, while emphasizing identification and treatment of malnutrition in these patients. We provide guidance for tailored dietary approaches during IBD remission, active disease, and intestinal failure. A healthy Mediterranean die

Pre-conception Folic Acid and Multivitamin Supplementation for the Primary and Secondary Prevention of Neural Tube Defects and Other Folic Acid-Sensitive Congenital Anomalies.

Wilson RD, Genetics Committee, Wilson RD, Audibert F, Brock JA, Carroll J · Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC · 2015

To provide updated information on the pre- and post-conception use of oral folic acid with or without a multivitamin/micronutrient supplement for the prevention of neural tube defects and other congenital anomalies. This will help physicians, midwives, nurses, and other health care workers to assist in the education of women about the proper use and dosage of folic acid/multivitamin supplementation before and during pregnancy. Published literature was retrieved through searches of PubMed, Medline, CINAHL, and the Cochrane Library in January 2011 using appropriate controlled vocabulary and key words (e.g., folic acid, prenatal multivitamins, folate sensitive birth defects, congenital anomaly risk reduction, pre-conception counselling). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English from 1985 and June 2014. Searches were updated on a regular basis and incorporated in the guideline to Jun

The use of folic acid for the prevention of neural tube defects and other congenital anomalies.

Wilson RD, Davies G, Désilets V, Reid GJ, Summers A, Wyatt P · Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC · 2003

To provide information regarding the use of folic acid for the prevention of neural tube defects (NTDs) and other congenital anomalies, in order that physicians, midwives, nurses, and other health-care workers can assist in the education of women in the preconception phase of their health care. OPTION: Folic acid supplementation is problematic, since 50% of pregnancies are unplanned and the health status of women may not be optimal. Folic acid supplementation has been proven to decrease or minimize specific birth defects. A systematic review of the literature, including review and peer-reviewed articles, government publications, the previous Society of Obstetricians and Gynaecologists of Canada (SOGC) Policy Statement of March 1993, and statements from the American College of Obstetrics and Gynecology, was used to develop a new clinical practice guideline for the SOGC. Peer-review process within the committee structure. The benefit is reduced lethal and severe morbidity birth defec

Regression of gastroesophageal reflux disease symptoms using dietary supplementation with melatonin, vitamins and aminoacids: comparison with omeprazole.

Pereira Rde S · Journal of pineal research · 2006 · n=176

The prevalence of gastroesophageal reflux disease (GERD) is increasing. GERD is a chronic disease and its treatment is problematic. It may present with various symptoms including heartburn, regurgitation, dysphagia, coughing, hoarseness or chest pain. The aim of this study was to investigate if a dietary supplementation containing: melatonin, l-tryptophan, vitamin B6, folic acid, vitamin B12, methionine and betaine would help patients with GERD, and to compare the preparation with 20 mg omeprazole. Melatonin has known inhibitory activities on gastric acid secretion and nitric oxide biosynthesis. Nitric oxide has an important role in the transient lower esophageal sphincter relaxation (TLESR), which is a major mechanism of reflux in patients with GERD. Others biocompounds of the formula display anti-inflammatory and analgesic effects. A single blind randomized study was performed in which 176 patients underwent treatment using the supplement cited above (group A) and 175 received treatm

Micronutrients in Autoimmune Diseases: Shining a Light on Vitamin D, Cobalamin, Folate, and Iron Metabolism.

Triggianese P, Ramirez GA, Cedola F, Nicola S, Costanzo G, Brussino L · Nutrients · 2026

Background: Autoimmune diseases (AIDs) are characterized by chronic inflammation and tissue damage resulting from abnormal immune responses. While genetic and environmental factors play significant roles in disease development, essential micronutrient deficiencies (MNDs) represent a critical and often overlooked contributor. Methods: This review examines the interactions between micronutrients and immune cells, focusing on vitamin D, vitamin B12, folate (FA), and iron, and their roles in AIDs, such as rheumatoid arthritis, autoimmune thyroid disorders, multiple sclerosis, systemic lupus erythematosus, and other connective tissue diseases. We explore the immunomodulatory effects of these micronutrients, their impact on immune tolerance, and the mechanisms by which MNDs contribute to disease progression. Results: MNDs are commonly observed in patients with AIDs and are associated with worsening immune dysregulation, increased inflammation, and disease severity. Vitamin D plays a pivotal

Vitamin B12 Deficiency: Common Questions and Answers.

Patel H, McGuirk R · American family physician · 2025

Vitamin B12 deficiency occurs in approximately 2% to 3% of adults in the United States. Risk factors include malabsorptive processes, limited dietary intake of vitamin B12, use of certain medications (eg, metformin, proton pump inhibitors), and older age. Symptoms vary based on the severity of vitamin B12 deficiency but may include fatigue, brain fog, depression, peripheral neuropathy, and ataxia. Although universal screening is not recommended, testing should be considered in patients with at least one risk factor for and one clinical feature of vitamin B12 deficiency. Initial testing includes total serum vitamin B12 level, which is diagnostic for deficiency if less than 180 pg/mL. Borderline levels (180-350 pg/mL) warrant a methylmalonic acid measurement, which is diagnostic for vitamin B12 deficiency if elevated. Patients without a clear cause of deficiency should undergo further testing for atrophic gastritis with a Helicobacter pylori test and evaluation for autoantibodies associa

A long-standing undiagnosed case of vitamin B12 deficiency: a case report.

Mesgarankarimi A, Rezapour M, Tabrizi N · Journal of medical case reports · 2025

Pernicious anemia, an autoimmune disease, presents with gradual, nonspecific symptoms, often leading to delayed diagnosis owing to its overlap with other conditions and variability in laboratory findings, such as neurological symptoms without anemia or macrocytosis. This case describes a 40-year-old Iranian woman with a decade-long history of nonspecific symptoms, including fatigue, widespread musculoskeletal pain, paresthesia, cognitive disturbances, and optic neuritis; misattributed to conditions such as fibromyalgia, hypothyroidism, and autoimmune diseases. Despite annual monitoring for normocytic anemia, her critically low vitamin B12 levels (< 150 pg/mL) and a diagnosis of pernicious anemia were identified only after persistent symptoms prompted further evaluation, revealing atrophic gastritis as the underlying cause. Neurologic improvement with parenteral B12 therapy, alongside management of fibromyalgia, emphasizes the importance of considering vitamin B12 defici

Vitamin B12

NIH/MedlinePlus

General information for the public about Vitamin B12, its role in the body, deficiency symptoms, and dietary sources.

Vitamin B12 or folate deficiency anaemia

National Health Service (NHS)

This NHS page details the causes, symptoms, diagnosis, and treatment of vitamin B12 and folate deficiency anaemia, offering patient-friendly information.

Cobalamin Supplementation During Infancy; Effect on B-vitamin Status, Growth and Psychomotor Development

n=107 · NCT00479479 · COMPLETED · COMPLETED

Adequate levels of vitamin B12 (cobalamin) is necessary for normal growth and development in infants. We have earlier investigated cobalamin status in healthy children and we observed metabolic evidence of impaired cobalamin status during the first 6 months, but not later in life. The purpose of this study is to determine if cobalamin supplementation may influence the metabolic profile related to cobalamin status in infants.

Evaluating the Impact of B Vitamin Supplementation (Soloways™) on Homocysteine and LDL-C Levels in Patients With MTHFR, MTR, and MTRR Polymorphisms: A Randomized, Double-blind, Placebo-controlled Trial

n=54 · NCT06163443 · COMPLETED · COMPLETED

This randomized, double-blind, placebo-controlled trial will evaluate the impact of methylfolate, pyridoxal-5'-phosphate (P5P), and methylcobalamin supplementation on homocysteine and LDL-C levels in individuals with low to medium cardiac risk and MTHFR, MTR, and MTRR gene polymorphisms. The study aims to explore the efficacy of these vitamins in reducing homocysteine levels, a critical risk factor for cardiovascular disease (CVD), while also monitoring LDL-C levels. The findings will offer valuable insights into personalized CVD prevention and management, emphasizing the significance of genetic factors in nutritional therapy.

Assessment of Functional Vitamin B12 Deficiency in Mexican Women

n=180 · NCT00826657 · COMPLETED · COMPLETED

We hope to learn the clinical and functional signs of sub-clinical vitamin B12 deficiency and its response to supplementation in non-anemic, non-pregnant, and non-lactating women in Rural Mexico. Vitamin B12 is important in hematopoiesis, neuro-cognitive functions and genetic integrity. However vitamin B12 is only found in animal source foods therefore a large segment of the population in developing countries and those practicing vegetarianism are at risk of deficiency of the vitamin. This information will help decide weather supplementation with vitamin B12 is necessary in such populations for public health reasons.

Vitamin B12 Deficiency

TRIP Database

TRIP Database offers a federated search across multiple evidence sources, including clinical guidelines, systematic reviews, and evidence-based synopses related to vitamin B12 deficiency.

Vitamin B12 monograph

Natural Medicines Database

This monograph details scientific evidence for Vitamin B12, covering its efficacy and safety for various health concerns. It includes information on its role in metabolic processes and potential therapeutic uses.