Vitamin B12 deficiency after total gastrectomy for gastric cancer, prevalence, and symptoms: a systematic review and meta-analysis.

PURPOSE: Nutrient deficiency is one of the common complications in patients who undergo gastrectomy, especially those vitamins and minerals absorbed in the stomach or by substances in the gastric juice, such as vitamin B12. Hence, this systematic review and meta-analysis were conducted for the first time to investigate the prevalence of vitamin B12 deficiency and its symptoms in gastric cancer (GC) patients who underwent gastrectomy. METHOD: PubMed, Scopus, Google Scholar, and Web of Science databases were searched to find related studies. After screening, studies were selected based on the abstract and title of related studies. The heterogeneity and inconsistency between studies were evaluated using Cochran's Q, I 2 tests. Egger's test analyzed publication bias for studies. A 95% confidence interval (95% CI) was used to estimate the overall prevalence of vitamin B12 deficiency. RESULTS: Fourteen studies, including 2627 GC patients who underwent surgery, were included in the study. The mean age of the patients in this study was 61.2 ±â€…4.93 years. The pooled estimate of meta-analysis results showed that the prevalence of vitamin B12 deficiency after gastrectomy in patients with GC was 48.8% (95% CI:32.4, 65.2%, I 2 : 98.85, τ 2  = 0.05, Q (13) = 1127.8, P  < 0.001). The most important symptoms were anemia, fatigability, cold feet or legs, numbness, and dizziness. CONCLUSION AND RECOMMENDATION: Vitamin B12 deficiency has a high prevalence among patients who have undergone gastrectomy, and it is necessary to pay enough attention to treating these patients after surgery to prevent its complications.

Vitamin B12 insufficiency and deficiency: a review of nondisease risk factors.

Vitamin B12 deficiency and insufficiency can lead to both hematological and neurological impairments. This review examines nondisease causes and risk factors associated with dietary availability, such as eating habits, food processing, cooking techniques, and bioavailability, as well as increased physiological needs and iatrogenic factors linked to medication use or surgical procedures. As a result of these nondisease influences, groups at higher risk include vegans, vegetarians, older adults, individuals with limited diets, breastfed and preterm infants, and those who primarily consume foods prepared or cooked in ways that reduce vitamin B12 content, as well as individuals on certain medications or who have undergone specific surgeries. Recognizing these diverse risk factors helps develop strategies for prevention and intervention to minimize the adverse health effects related to B12 deficiency and insufficiency.

Vitamin B12: For more than just the treatment of megaloblastic anemia?

Vitamin B12, or cobalamin, belongs to the group of water-soluble vitamins and is ingested through food of animal origin such as eggs, milk, red meat and poultry, fish, and shellfish. Its clinical indication is the treatment of hypovitaminosis B12 administered orally or intramuscularly in the form of hydroxocobalamin. Hypovitaminosis B12 is mainly caused by deficient dietary intake (individuals with malnutrition, vegetarians or vegans, older adults, pregnant people, individuals with alcohol use disorder); when intestinal absorption is reduced (atrophic gastritis, malabsorption syndrome, gastrointestinal surgery); and for causes associated with the intake of drugs (antacids, metformin). Hypervitaminosis B12 has been associated with renal failure; liver diseases such as cirrhosis and acute-phase hepatitis; alcohol use disorder with or without liver involvement; solid tumors of the lung, liver, esophagus, pancreas, and colorectum; and in hematological malignancies such as leukemia and bone marrow dysplasia.

Clinical Course of Vitamin B12 Deficiency and Associated Risk Factors in Patients After Total Gastrectomy for Gastric Cancer.

BACKGROUND/AIM: Patients are at-risk for vitamin B12 deficiency after total gastrectomy due to a lack of intrinsic factors. The aim of the study was to clarify the clinical course and risk factors for vitamin B12 deficiency after total gastrectomy for gastric cancer patients. PATIENTS AND METHODS: Patients who underwent curative resection for gastric cancer were selected from the medical records of the Yokohama City University from 2000 to 2020. A logistic regression analysis was performed to identify risk factors for vitamin B12 deficiency. RESULTS: We evaluated 47 patients. The median serum vitamin B12 levels before surgery were 359 pg/ml, while those at 3, 6, 9, and 12 months after surgery these were 255 pg/ml, 197.5 pg/ml, 195 pg/ml, and 206 pg/ml, respectively. Univariate analyses to identify factors associated with vitamin B12 deficiency at 6 months after surgery showed that the occurrence of postoperative complications was a significant risk factor (OR=6.347, 95%CI=1.607-25.774, p=0.009), while adjuvant chemotherapy was a marginally significantly risk factor (OR=3.562, 95%CI=0.877-14.477, p=0.076). CONCLUSION: Almost half of the patients were diagnosed with vitamin B12 deficiency at 6 months after total gastrectomy for gastric cancer. In addition, the occurrence of postoperative complications and adjuvant chemotherapy were risk factors for vitamin B12 deficiency at 6 months after surgery.

Vitamin B12 supplementation post-gastrectomy: a service closed-loop audit at St. James's Hospital, Dublin.

BACKGROUND: Vitamin B12 (VB12) deficiency is a well-described complication post-gastrectomy. It is caused by the loss of parietal cell mass leading to megaloblastic anaemia. This closed-loop audit assesses patient understanding of and adherence with VB12 supplementation guidelines post-gastrectomy. METHODS: A closed-loop audit cycle was performed. After the first cycle, an educational intervention was actioned prior to re-audit. One hundred twenty-five patients who underwent gastrectomy between 2010 and 2020 were available for study (86 total gastrectomies (TG), 39 subtotal gastrectomies (STG)). Twenty-nine patients who had not been adherent with VB12 supplementation/surveillance were eligible for re-audit. RESULTS: 91.9% (79/86) of TG patients reported adherence in regular parenteral VB12 supplementation. Adherence was significantly lower for STG for checking (and/or replacing) their VB12, with only 53.8% (21/39) checking their VB12 levels. 67/125 (53.6%) of the patients stated that they knew it was important to supplement B12 post-gastrectomy. 37.8% (43/113) of participants could explain why this was important, and 14.4% (18/125) had any knowledge of the complications of VB12 deficiency. Following re-audit, 5/8 (57.5%) of TG patients who had not been adherent with VB12 supplementation in the first cycle were now adherent with VB12 supplementation following our educational intervention. 7/17 (41.2%) of the STG group had received VB12 or made arrangements to receive supplemental VB12 if it was indicated. CONCLUSION: This study demonstrates good adherence in those undergoing TG. Patient understanding correlates with adherence, suggesting that patient education and knowledge reinforcement may be key to adherence with VB12 supplementation. A simple educational intervention can improve adherence with VB12 supplementation in patients undergoing gastrectomy.

The efficacy of vitamin B12 supplementation for treating vitamin B12 deficiency and peripheral neuropathy in metformin-treated type 2 diabetes mellitus patients: A systematic review.

BACKGROUND AND AIMS: Metformin-treated type 2 diabetes mellitus (T2DM) patients are at higher risk of vitamin B12 deficiency and more severe neuropathy symptoms. There is still no guideline suggesting vitamin B12 supplementation for this population. This study aimed to analyze the efficacy of vitamin B12 supplementation in this population. METHOD: Studies reporting the efficacy of vitamin B12 supplementation in metformin-treated T2DM patients were systematically searched in PubMed, Cochrane, EBSCOHost, and Scopus following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Additional relevant studies were searched manually through citations. Study quality and risk of bias were assessed using suitable tools. RESULTS: Seven clinical trials with a total of 506 participants were included. Using the Cochrane's Risk of Bias 2 tools for clinical trials, 4 studies were assessed to have high risk of bias and 3 studies had low risk of bias. There were 5 studies that measured changes in serum vitamin B12 level, all of which reported a statistically significant increase after supplementation. Significant reductions in homocysteine after supplementation were found in 2 studies. Its effect on neuropathy symptoms was still unclear, with 2 studies reporting a significant improvement and 1 study reporting no significant effect. CONCLUSIONS: The results of this systematic review support the implementation of vitamin B12 supplementation for metformin-treated T2DM to prevent or treat vitamin B12 deficiency and neuropathy. More high-quality clinical studies are required to generate quantitative analysis and to encourage supplementation in available guidelines.

Nitrous oxide in labour predicted newborn screening total homocysteine and is a potential risk factor for infant vitamin B12 deficiency.

AIM: Risk factors for vitamin B12 deficiency in infants are not fully understood. The aim of the study was to assess predictors of total homocysteine and methylmalonic acid analysed in newborn screening dried blood spots. METHODS: In a Norwegian case control study, we analysed total homocysteine and methylmalonic acid in newborn screening dried blood spots of 86 infants clinically diagnosed with vitamin B12 deficiency during 2012-2018. Results were compared to 252 healthy infants and 400 dried blood spot controls. Medical records were reviewed, and mothers completed questionnaires. RESULTS: Both total homocysteine and methylmalonic acid were significantly higher on newborn screening dried blood spots in infants later clinically diagnosed with vitamin B12 deficiency than controls. Multiple regression analysis showed that the dose of nitrous oxide during labour was the strongest predictor for total homocysteine level in newborn screening dried blood spots for all infants, with larger effect in infants later clinically diagnosed with vitamin B12 deficiency than controls. CONCLUSION: Nitrous oxide dose during labour was a predictor for total homocysteine and may impact the interpretation of total homocysteine analysis in newborn screening. Nitrous oxide is suggested as a contributing risk factor for infants prone to develop vitamin B12 deficiency.

Phase II Study of a Multi-center Randomized Controlled Trial to Evaluate Oral Vitamin B12 Treatment for Vitamin B12 Deficiency After Total Gastrectomy in Gastric Cancer Patients.

BACKGROUND/AIM: This prospective multi-central randomized phase II trial evaluated the efficacy and safety of oral Vitamin B12 500 µg/day replacement compared with oral Vitamin B12 1,500 µg/day in patients with Vitamin B12 deficiency after total gastrectomy for gastric cancer. PATIENTS AND METHODS: Patients were randomly assigned to receive oral Vitamin B12 500 µg/day or Vitamin B12 1,500 µg/day in a 1:1 ratio with a minimization method. The primary endpoint was the incidence of a normal serum Vitamin B12 level at three months after treatment. RESULTS: From January 2018 to December 2021, 3 institutions collaborated with the present study, and 74 patients were registered from these 3 institutions. The study was prematurely closed due to poor accrual after reaching almost 50% of its goal. Among the 74 recruited patients, 36 were allocated to the Vitamin B12 500 µg/day arm and 38 to Vitamin B12 1,500 µg/day arm. The incidences of patients with a normal Vitamin B12 level at 3 months (serum Vitamin B12 level >200 pg/ml) were 91.7% (33/36) in the Vitamin B12 500 µg/day arm and 100% (38/38) in the Vitamin B12 1,500 µg/day arm (p=0.3587). The types of clinical symptoms with Vitamin B12 deficiency that improved with Vitamin B12 treatment and the degree of improvement were also similar. CONCLUSION: Although the primary endpoint of the present study was not met, it was found that oral Vitamin B12 500 µg/day replacement is as effective and safe as oral Vitamin B12 1,500 µg/day replacement for Vitamin B12 deficiency.

Vitamin B12 absorption and malabsorption.

Vitamin B12 is assimilated and transported by complex mechanisms that involve three transport proteins, intrinsic factor (IF), haptocorrin (HC) and transcobalamin (TC) and their respective membrane receptors. Vitamin deficiency is mainly due to inadequate dietary intake in vegans, and B12 malabsorption is related to digestive diseases. This review explores the physiology of vitamin B12 absorption and the mechanisms and diseases that produce malabsorption. In the stomach, B12 is released from food carrier proteins and binds to HC. The degradation of HC by pancreatic proteases and the pH change trigger the transfer of B12 to IF in the duodenum. Cubilin and amnionless are the two components of the receptor that mediates the uptake of B12 in the distal ileum. Part of liver B12 is excreted in bile, and undergoes an enterohepatic circulation. The main causes of B12 malabsorption include inherited disorders (Intrinsic factor deficiency, Imerslund-Gräsbeck disease, Addison's pernicious anemia, obesity, bariatric surgery and gastrectomies. Other causes include pancreatic insufficiency, obstructive Jaundice, tropical sprue and celiac disease, bacterial overgrowth, parasitic infestations, Zollinger-Ellison syndrome, inflammatory bowel diseases, chronic radiation enteritis of the distal ileum and short bowel. The assessment of B12 deficit is recommended in the follow-up of subjects with bariatric surgery. The genetic causes of B12 malabsorption are probably underestimated in adult cases with B12 deficit. Despite its high prevalence in the general population and in the elderly, B12 malabsorption cannot be anymore assessed by the Schilling test, pointing out the urgent need for an equivalent reliable test.

Vitamin B12 deficiency.

Of the water-soluble vitamins, vitamin B12 (B12) has the lowest daily requirement. It also has several unique properties including a complex pathway for its absorption and assimilation requiring intact gastric and terminal small intestinal function, an enterohepatic pathway, and several dedicated binding proteins and chaperons. The many causes of B12 deficiency include malabsorption and defects in cellular delivery and uptake, as well as limited dietary intake. B12 is required as a cofactor for only two reactions in humans, the cytosolic methionine synthase reaction and the mitochondrial methymalonyl CoA mutase reaction. Disruption of either of these reactions gives rise to B12 deficiency. Although more common with advancing age, because of the higher prevalence of malabsorptive disorders in the elderly, B12 deficiency is widely distributed across all age groups particularly where food insecurity occurs. The consequences and severity of B12 deficiency are variable depending on the degree of deficiency and its duration. Major organ systems affected include the blood, bone marrow and nervous system. Megaloblastic anemia results from a defect in thymidine and therefore DNA synthesis in rapidly dividing cells. Nervous system involvement is varied, some of which results from defective myelin synthesis and repair. Cognitive impairment and psychosis may also occur. Diagnosis of B12 deficiency rests on clinical suspicion followed by laboratory testing, which consists of a panel of tests, that together provide clinically reliable predictive indices. B12 metabolism and deficiency is closely intertwined with folate, another B-vitamin. This chapter explores the various aspects of a unique and fascinating micronutrient.

Evaluation of the response to vitamin B12 supplementation in patients with atrophy in sleeve gastrectomy materials.

OBJECTIVE: Vitamin B12 deficiency can be seen in the cases with sleeve gastrectomy. Because the chief factor in vitamin B12 deficiency is gastric atrophy, we aimed to evaluate the effect of atrophy on postoperative vitamin B12 levels in patients who underwent sleeve gastrectomy. MATERIAL AND METHODS: Sixty patients were included in this study. Vitamin B12 levels were compared with presence of atrophy before the operation and after vitamin B12 supplementation. RESULTS: Atrophy was observed in 37 (61.7%) of the cases; 23 (38.3%) patients had no atrophy. There was a statistically significant difference between the presence of atrophy and vitamin B12 levels (p = 0.024). Despite vitamin B12 support, there were statistically significant low vitamin B12 levels after the operation in female patients having atrophy (p = 0.023). The same significance was not observed in males (p = 0.480). CONCLUSION: Vitamin B12 deficiency following obesity surgery is a condition that must be monitored and prevented. We found that histopathologically confirmed atrophy had an adverse effect on postoperative vitamin B12 levels. These findings can be a guide for the clinicians in the management of these cases.

OBJETIVO: La deficiencia de vitamina B12 se puede observar en los casos de gastrectomía en manga. Debido a que el factor principal en la deficiencia de vitamina B12 es la atrofia gástrica, nuestro objetivo fue evaluar el efecto de la atrofia en los niveles posoperatorios de vitamina B12 en pacientes que se sometieron a gastrectomía en manga. MATERIAL Y MÉTODOS: se incluyeron 60 pacientes en este estudio. Los niveles de vitamina B12 se compararon con la presencia de atrofia antes de la operación y después de la suplementación con vitamina B12. RESULTADOS: Se observó atrofia en 37(61.7%) de los casos; 23 (38.3%) pacientes no presentaron atrofia. Hubo una diferencia estadísticamente significativa entre la presencia de atrofia y los niveles de vitamina B12 (p = 0.024). A pesar del apoyo de vitamina B12, hubo niveles bajos de vitamina B12 estadísticamente significativos después de la operación en pacientes femeninas con atrofia (p = 0.023). No se observó la misma significación en los hombres (p = 0.480). CONCLUSIONES: La deficiencia de vitamina B12 luego de una cirugía de obesidad es una condición que debe ser monitoreada y prevenida. Encontramos que la atrofia confirmada histopatológicamente tuvo un efecto adverso sobre los niveles posoperatorios de vitamina B12. Estos hallazgos pueden ser una guía para los médicos en el manejo de estos casos.

Vitamin B12 and gut-brain homeostasis in the pathophysiology of ischemic stroke.

Stroke is a leading cause of morbidity and mortality worldwide. It inflicts immeasurable suffering on patients and their loved ones and carries an immense social cost. Efforts to mitigate the impact of stroke have focused on identifying therapeutic targets for the prevention and treatment. The gut microbiome represents one such potential target given its multifaceted effects on conditions known to cause and worsen the severity of stroke. Vitamin B12 (VB12) serves as a cofactor for two enzymes, methylmalonyl-CoA synthase and methionine synthase, vital for methionine and nucleotide biosynthesis. VB12 deficiency results in a buildup of metabolic substrates, such as homocysteine, that alter immune homeostasis and contribute to atherosclerotic disorders, including ischemic stroke. In addition to its support of cellular function, VB12 serves as a metabolic cofactor for gut microbes. By shaping microbial communities, VB12 further impacts local and peripheral immunity. Growing evidence suggests that gut dysbiosis-related immune dysfunction induced by VB12 deficiency may potentially contributes to stroke pathogenesis, its severity, and patient outcomes. In this review, we discuss the complex interactions of VB12, gut microbes and the associated metabolites, and immune homeostasis throughout the natural history of ischemic stroke.

Associations of atrophic gastritis and proton-pump inhibitor drug use with vitamin B-12 status, and the impact of fortified foods, in older adults.

BACKGROUND: Atrophic gastritis (AG) and use of proton pump inhibitors (PPIs) result in gastric acid suppression that can impair the absorption of vitamin B-12 from foods. The crystalline vitamin B-12 form, found in fortified foods, does not require gastric acid for its absorption and could thus be beneficial for older adults with hypochlorhydria, but evidence is lacking. OBJECTIVES: To investigate associations of AG and PPI use with vitamin B-12 status, and the potential protective role of fortified foods, in older adults. METHODS: Eligible participants (n = 3299) not using vitamin B-12 supplements were drawn from the Trinity-Ulster and Department of Agriculture cohort, a study of noninstitutionalized adults aged ≥60 y and recruited in 2008-2012. Vitamin B-12 status was measured using 4 biomarkers, and vitamin B-12 deficiency was defined as a combined indicator value < -0.5. A pepsinogen I:II ratio <3 was considered indicative of AG. RESULTS: AG was identified in 15% of participants and associated with significantly lower serum total vitamin B-12 (P < 0.001) and plasma holotranscobalamin (holoTC; P < 0.001), and higher prevalence of vitamin B-12 deficiency (38%), compared with PPI users (21%) and controls (without AG and nonusers of PPIs; 15%; P < 0.001). PPI drugs were used (≥6 mo) by 37% of participants and were associated with lower holoTC concentrations, but only in participants taking higher doses (≥30 mg/d). Regular, compared with nonregular, consumption of fortified foods (i.e., ≥5 and 0-4 portions/wk, respectively) was associated with higher vitamin B-12 biomarkers in all participants, but inadequate to restore normal vitamin B-12 status in those with AG. CONCLUSIONS: Older adults who have AG and/or use higher doses of PPIs are more likely to have indicators of vitamin B-12 deficiency. Fortified foods, if consumed regularly, were associated with enhanced vitamin B-12 status, but higher levels of added vitamin B-12 than currently provided could be warranted to optimize status in people with AG.

Clinical and radiological features of main dementias / Aspectos clínicos e radiológicos das principais demências

Dementia is a syndrome characterized by a decline of two or more cognitive functions, affecting social or professional life. Alzheimer's Disease is a neurodegenerative disorder that represents 53% of dementia cases; memory loss, inability to recognize faces, impaired judgement, disorientation and confusion are possible common symptoms. Vascular Dementia is responsible for 42% of dementia cases, due to cerebrovascular pathologies, and the clinical aspects are related to the extension and location of the brain injury. Lewy Bodies Dementia is a neurodegenerative disorder that represents 15% of dementia cases, and its symptoms include visual hallucinations, parkinsonism and fluctuating cognitive decline. Frontotemporal dementia is a group of clinical syndromes, divided in Behavioral-variant, characterized by disinhibition, compulsions, apathy, aberrant sexual behavior and executive dysfunction; and Primary Progressive Aphasia, which is subdivided in Nonfluentvariant and Semantic-variant. Vitamin B12 deficiency is a reversible cause of dementia, with a wide clinical feature, that includes psychiatric symptoms such as depression and irritability, hematological symptoms related to anemia (e.g. dyspnea and fatigue), and neurological symptoms including dementia and neuropathy. Normal pressure hydrocephalus is also reversible, presenting forgetfulness, changes in mood, decline of executive functions, reduced attention, and a lack of interest in daily activities as symptoms. The radiological findings vary depending on the etiology of dementia. For that reason, understanding neuroimaging and clinical aspects is important to diagnose effectively.

A demência é uma síndrome que consiste em um declínio de um ou mais domínios cognitivos, que afeta o desempenho social ou profissional do indivíduo. A Doença de Alzheimer é um transtorno neurocognitivo que representa 53% dos casos de demência; seus sintomas podem incluir perda de memória, incapacidade de reconhecer rostos familiares, julgamento comprometido desorientação e confusão mental. A Demência Vascular é responsável por 42% dos casos de demência e é causada por doenças cerebrovasculares, seus achados clínicos são relacionados com o local e com a extensão do dano cerebral. Já a Demência por Corpos de Lewy é uma doença neurocognitiva que representa 15% dos casos de demência, cujos sintomas incluem alucinações visuais, parkinsonismo e flutuação cognitiva. A Demência Frontotemporal, por sua vez, é um grupo de síndromes, que se dividem em variante comportamental ­ caracterizada por desinibição, compulsão, apatia, hipersexualidade e disfunções executivas ­ e Afasia Progressiva Primária, subdividida em variante não-fluente e variante semântica, que cursam com disfunções da linguagem. Há, ainda, a Deficiência de Vitamina B12, uma causa reversível de demência. Ela possui um quadro clínico variado, que inclui sintomas psiquiátricos, como depressão e irritabilidade, sintomas hematológicos relacionados a anemia, como dispneia e fadiga) e sintomas neurológicos, que incluem demência e neuropatias. Uma outra causa reversível é a Hidrocefalia de Pressão Normal, que se apresenta com esquecimentos, alterações de humor, perda de função executiva e redução da atenção e do interesse nas atividades cotidianas. Os achados de neuroimagem variam dependendo da etiologia da demência. Assim, compreender os aspectos clínicos e radiológicos é importante para um diagnóstico efetivo..

[Thromboembolic event and metabolic hyperhomocysteinemia: A case report and review of literature]. / Événement thromboembolique et hyperhomocystéinémie métabolique : case-report et revue de la littérature.

INTRODUCTION: Venous thromboembolic diseases have an incidence of 1.57/1000. Among patients under 50 years old, thrombophilia is assessed, the indications for which are increasingly stringent. Today, the need of plasma homocysteine assay is uncertain. OBSERVATION: Our case is a 42 year-old man, in whom a pulmonary embolism associated with macrocytosis made us discover a B12 deficiency secondary to Biermer's disease. In the literature, patients are men with an average age limit to the realisation of the assessment of thrombophilia. Not all of these patients had any causal other than hyperhomocysteinemia secondary to Biermer's disease. The support is not detailed. CONCLUSION: Hyperhomocysteinemia is probably not the only thromboembolic factor. The patient received anticoagulation and vitamin B12 supplementation. A good reading of the complete blood count is essential.

[Thromboembolisms due to recreational use of nitrous oxide]. / Trombo-embolieën door recreatief lachgasgebruik.

Nitrous oxide (N2O) is increasingly used as a recreational drug, and is presumed relatively safe and innocent. The risks for neurological complications are often known, however the risks of serious thromboembolic events are not. We describe three cases of acute thromboembolic events resulting in serious cardiovascular complications after N2O abuse: one case of myocardial infarction that resulted in a reduced ejection fraction, one case of peripheral arterial occlusion that led to limb amputation and one case of pulmonary embolism that resulted in hemodynamic instability requiring extracorporeal membrane oxygenation (ECMO) and surgical removal. All patients were young adults with a low cardiovascular risk profile. N2O inactivates vitamin B12, leading to vitamin B12 deficiency and subsequent to hyperhomocysteinemia, which is associated with the formation of fibrinolysis-resistant blood thrombi. In conclusion, we contest the safety and innocence of recreational N2O (ab)use. Our three cases illustrate that, next to previously described neurological complications, the use of nitrous oxide is associated with thromboembolic cardiovascular complications, presumably mediated by hyperhomocysteinemia.

Long-Term Iron and Vitamin B12 Deficiency Are Present after Bariatric Surgery, Despite the Widespread Use of Supplements.

There are few long-term nutritional studies in subjects undergoing bariatric surgery that have assessed weight regain and nutritional deficiencies. In this study, we report data 8 years after surgery on weight loss, use of dietary supplements and deficit of micronutrients in a cohort of patients from five centres in central and northern Italy. The study group consisted of 52 subjects (age: 38.1 ± 10.6 y, 42 females): 16 patients had Roux-en-Y gastric bypass (RYGB), 25 patients had sleeve gastrectomy (SG) and 11 subjects had adjustable gastric banding (AGB). All three bariatric procedures led to sustained weight loss: the average percentage excess weight loss, defined as weight loss divided by excess weight based on ideal body weight, was 60.6% ± 32.3. Despite good adherence to prescribed supplements, 80.7% of subjects (72.7%, AGB; 76.7%, SG; 93.8 %, RYGB) reported at least one nutritional deficiency: iron (F 64.3% vs. M 30%), vitamin B12 (F 16.6% vs. M 10%), calcium (F 33.3% vs. M 0%) and vitamin D (F 38.1% vs. M 60%). Long-term nutritional deficiencies were greater than the general population among men for iron and among women for vitamin B12.

Enteral Vitamin B12 Supplementation Is Effective for Improving Anemia in Patients Who Underwent Total Gastrectomy.

BACKGROUND: This study aimed to investigate the efficacy of enteral supplementation of vitamin B12 for vitamin B12 deficiency in patients who underwent total gastrectomy for gastric cancer. METHODS: The study enrolled 133 patients who underwent total gastrectomy for gastric cancer at Kochi Medical School. Clinical data were obtained to investigate associations between vitamin B12 supplementation and vitamin B12 levels. Vitamin B12 deficiency was defined as serum vitamin B12 less than 200 pg/mL. Baseline characteristics and changes in hematological variables, including vitamin B12 levels, were examined. RESULTS: Vitamin B12 deficiency was present in 71.4% of the 133 patients. Vitamin B12 levels at 3, 6, and 12 months after enteral supplementation were 306 pg/mL, 294 pg/mL, and 367 pg/mL, respectively, which were all significantly higher than those before supplementation (p < 0.001 for all comparisons). The median red blood cell count at 3, 6, and 12 months after enteral supplementation were 380 × 104/mm3, 394 × 104/mm3, and 395 × 104/mm3, respectively, which were all significantly higher than those before supplementation (p = 0.020, p = 0.001, and p = 0.003, respectively). Vitamin B12 levels at 3, 6, and 12 months after supplementation were significantly higher in patients supplemented enterally than those supplemented parenterally (p < 0.001 for all comparisons). CONCLUSIONS: Vitamin B12 deficiency was found in 71.4% of postoperative patients who underwent total gastrectomy for gastric cancer, and enteral vitamin B12 supplements might be effective to improve anemia in these patients.

Is There a Carcinogenic Risk Attached to Vitamin B12 Deficient Diets and What Should We Do About It? Reviewing the Facts.

The number of individuals partaking in veganism has increased sharply in the last decade. Therefore, it is critical to look at the implications of vegan diets for public health. Although there are multiple health benefits of a vegan diet, studies have also linked the diet with deficiencies in various micronutrients. This study focuses on vitamin B12, because of its critical role in DNA synthesis and methylation. In light of these connections, a critical review of recent scientific literature is conducted to understand the effects of a B12 deficient diet on the genome and epigenome, and whether it can give rise to cancer. It is observed that a B12 deficiency leads to increased uracil misincorporation, leading to impaired DNA synthesis and genomic instability. The deficiency also leads to global hypomethylation of DNA, a hallmark of early carcinogenesis. The findings of this study highlight the need for increased awareness among vegans to ensure adequate B12 intake through supplementation or consumption of fortified products as a preventative measure. Additionally, the biofortification of staple crops and an improved version of fermented products with increased B12 content can be developed when inadequate intake seems otherwise inevitable.

Review of Vitamin B12 deficiency in pregnancy: a diagnosis not to miss as veganism and vegetarianism become more prevalent.

Vegetarianism and veganism are increasingly popular. The Food Standards Agency, biennial Food and You Survey of adults aged 16 years and over living in the UK, found that between 2012 and 2018 the proportion of people who reported never consuming dairy products had increased from 2% to 5%. However, veganism risks development of vitamin B12 deficiency as it is not available from plant sources. Moreover, its impact may be slow to be detected because body stores of vitamin B12 can last years. There is currently no published guidance on antenatal diagnosis and management of vitamin B12 deficiency. This paper reviews the metabolism, diagnosis and treatment of vitamin B12 in pregnancy. It concludes that national screening policymakers should consider introducing screening for B12 deficiency into the Antenatal and Newborn Screening Programmes for mothers and their infants if at risk of vitamin B12 deficiency. In the interim, national policy should be developed for prophylactic vitamin B12 supplementation in high-risk groups around the time of pregnancy.