Study of Correlation between Serum Vitamin B12 Level and Aberrant DNA Methylation in Infertile Males.

Introduction: Altered DNA methylation pattern in sperms has been associated with infertility in males demonstrating defective spermatogenesis or low semen quality. Vitamin B-12, by affecting 1-carbon metabolism pathways, might alter the DNA methylation pattern. We aimed to study the correlation of serum vitamin B12 levels with aberrant DNA methylation in infertile male patients. Methods: A cross-sectional study was conducted on 17 oligozoospermic infertile males (WHO criteria, 2010) and 10 healthy fertile males. Serum vitamin B12 levels were estimated using the chemiluminescence method. Global methylation was determined using the ELISA system (Imprint Methylated DNA Quantification Kit, Sigma-Aldrich). The levels of global DNA methylation were calculated and compared relative to the methylated (100%) control DNA provided with the kit. Results: Mean serum vitamin B12 concentration in the control group was higher than that of the case group. This difference in serum vitamin B12 concentration in both groups was found statistically significant. Although the results of this study show that oligozoospermic men have relatively lower global DNA methylation as compared to normozoospermic control, the values could not reach a statistically significant level. A small positive correlation was found between serum vitamin B12 levels and percent methylation defect (r = 0.14) but was statistically insignificant. Conclusion: Our study concludes that oligozoospermic infertile males have a significant deficiency of vitamin B12 as compared to normozoospermic fertile males. This study did not find any significant difference in global DNA methylation between the two groups. The present study does not suggest any correlation between serum vitamin B12 level and percent DNA methylation.

Fluorescence Studies on the Binding Affinity and Determination of Vitamin B12 in the Presence of Fibrinogen.

The binding properties between vitamin B12 (vitB12, cyanocobalamin) and fibrinogen (Fib) were investigated by UV-vis absorption and steady-state/three-dimentional (3D) fluorescence spectra techniques as well as molecular docking. The experimental results showed that the intrinsic fluorescence of Fib quenched by vitB12 with static mechanism to form a non-fluorescent complex. The positive signs of thermodynamic parameters, ΔH (92.18 kJ/mol) and ΔS (433.5 J/molK), indicated that the hydrophobic forces were dominant in the binding mode. The molecular docking data were found to be in agreement with these experimental results and were confirmed by three hydrophobic interactions between the Trp430, Try390 residues of Fib and the vitamin. 3D spectra showed that fibrinogen undergoes a conformation change when it interacts with vitB12. Based on non-radiative energy transfer theory, binding distance was calculated to be 3.94 nm between donor (tryptophan residues of Fib) and acceptor (vitB12). The limit of detection (LOD) of vitB12 was calculated as 2.08 µM in the presence of fibrinogen. The relative standard deviation (RSD) of method was 4.28% for determinations (n = 7) of a vitB12 solution with the concentration of 7.80 µM.

Elevated Vitamin B12, Risk of Cancer, and Mortality: A Systematic Review.

Vitamin B12 (B12) is a molecule involved in several biological. Abnormally high levels are frequently found, but their causes can be multiple, and consequences have not been clearly elucidated. The objective of this review was to summarize the current evidence on the associations of elevated B12 and the development of cancer, and all-cause mortality in adults. Six references looking at mortality and seven looking at cancer risk were included. The evidence suggests an association between elevated B12 with a higher risk of cancer, with risk ratios ranging 1,88 to 5,9. There was less consistent evidence linking vitamin B12 and mortality.

Elevated B12 levels exceeding 1000 pg/L, if sustained and unexplainable, warrant a comprehensive individual assessment of each patient. This evaluation should encompass various potential factors contributing to the elevation, aiming to effectively guide the diagnostic process of neoplastic diseases.Clinical longitudinal observational studies have suggested a potential link between heightened B12 levels and the risks of cancer and mortality. Nonetheless, these studies have been retrospective cohort studies, and lack a defined threshold point of B12 levels.Studies have documented a positive correlation between elevated levels of B12 and the incidence of lung, pancreatic, and liver cancers, as well as certain hematological neoplasms, particularly those related to the myeloid lineage. Conversely, a consistent negative association has been observed in the context of breast cancer. Findings concerning neoplasms of the lower gastrointestinal tract and prostate display contradictory outcomes.The diagnostic significance of elevated B12 levels among patients already diagnosed with cancer remains uncertain and could potentially be linked to reverse causality.

'From highs to lows: a cautionary tale of nitrous oxide recreational use leading to sub-acute combined degeneration of the cord'.

BACKGROUND: Several causes lead to subacute combined degeneration (SACD) of the spinal cord, with nitrous oxide (N2O) inhalation rapidly emerging as the leading cause of functional Vitamin B12 deficiency [1]. CASE PRESENTATION: A 28-year-old man presented with numbness in the extremities and an unstable gait despite having a normal serum Vitamin B12 level. He also disclosed the recreational abuse of N2O. Magnetic Resonance Imaging (MRI) of the cervical spine revealed abnormal signals consistent with SACD. The patient's condition gradually improved after treatment with high dose Vitamin B12. Given the increasing number of N2O-induced SACD cases, the potential for drug abuse requires vigilance from clinicians. CONCLUSION: Healthcare providers are urged to inquire about a patient's history of N2O inhalation to prevent the missed diagnosis of SACD.

Biofortification, metabolomic profiling and quantitative analysis of vitamin B12 enrichment in guava juice via lactic acid fermentation using Levilactobacillus brevis strain KU15152.

BACKGROUND: Chemical fortification and dose supplementation of vitamin B12 are widely implemented to combat deficiency symptoms. However, in situ, fortification of vitamin B12 in food matrixes can be a promising alternative to chemical fortification. The present study aimed to produce vitamin B12-rich, probiotic guava juice fermented with Levilactobacillus brevis strain KU15152. Pasteurized fresh guava juice was inoculated with 7.2 log CFU mL-1 L. brevis strain KU15152 and incubated for 72 h at 37 °C anaerobically. The antioxidants, total phenolic compounds, vitamin B12 production, sugars, organic acids, pH and viable count were analyzed at 24, 48 and 72 h of incubation. The fermented juice was stored at 4 °C, and the changes in its functional properties were analyzed at 7-day intervals up to 28 days of storage. RESULTS: During fermentation, the bacteria cell count was increased from 7.01 ± 0.06 to 9.76 ± 0.42 log CFU mL-1 after 72 h of fermentation and was decreased to 6.94 ± 0.34 CFU mL-1 during storage at 4 °C after 28 days. The pH, total soluble solids, crude fiber, citric acid and total sugars decreased, while titratable acidity, total protein, antioxidants, phenolic compounds and lactic acid contents increased during fermentation. The fermented guava juice exhibited higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS)) radical scavenging activities (85.97% and 75.97%, respectively) at 48 h of fermentation. The concentration of active vitamin B12 in the sample reached 109.5 µg L-1 at 72 h of fermentation. However, this concentration gradually decreased to 70.2 µg L-1 during the storage period. During storage for 28 days at 4 °C, both the fermented and control guava juices exhibited a decline in antioxidant and phenolic compound concentrations. Furthermore, the addition of 20% honey and guava flavor enhanced the organoleptic properties and acceptability of fermented guava juice. CONCLUSION: The value-added fermented guava juice could be a novel functional food product to combat vitamin B12 deficiency. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Significance of Lignocellulosic Raw Materials on the Pore Structure of Activated Carbons Prepared by Steam Activation.

Five different lignocellulosic raw materials (coconut shells, Moso bamboo, sawtooth oak, Chinese fir, and Masson pine) were used to prepare activated carbons by steam activation at 850 °C to evaluate the effects of their structures on physical activation. The chemical compositions, botanic forms, and pore structures of the lignocellulose-based charcoal samples were systematically characterized by proximate and ultimate analyses, scanning electron microscopy, and mercury injection porosimetry. It was found that the rate of the activation reaction between charcoal and steam is determined by the porosity of the precursor. Pore structure results show that the steam activation of coconut shell and bamboo charcoals primarily produced micropores, thus yielding microporous activated carbon materials with just a few mesopores, even following a high burn-off of >66%. The steam activation of sawtooth oak charcoals produced mainly micropores at a low burn-off of <50% and both micropores and mesopores at a high burn-off of >50%. The steam activation of Chinese fir and Masson pine charcoals produced mainly mesopores at a burn-off of 0-80%. These mesopores were remarkably broadened to >20 nm on extending the activation time, resulting in a high vitamin B12 (VB12) adsorption capacity of ~530 mg/g. In conclusion, the raw lignocellulosic materials used as precursors have a decisive effect on the development of pore structures in activated carbon materials obtained through physical activation.

Autoimmune Gastritis and Hypochlorhydria: Known Concepts from a New Perspective.

Autoimmune atrophic gastritis is an immune-mediated disease resulting in autoimmune destruction of the specialized acid-producing gastric parietal cells. As a consequence, in autoimmune atrophic gastritis, gastric acid secretion is irreversibly impaired, and the resulting hypochlorhydria leads to the main clinical manifestations and is linked, directly or indirectly, to the long-term neoplastic complications of this disease. In the last few years, autoimmune atrophic gastritis has gained growing interest leading to the acquisition of new knowledge on different aspects of this disorder. Although reliable serological biomarkers are available and gastrointestinal endoscopy techniques have substantially evolved, the diagnosis of autoimmune atrophic gastritis is still affected by a considerable delay and relies on histopathological assessment of gastric biopsies. One of the reasons for the diagnostic delay is that the clinical presentations of autoimmune atrophic gastritis giving rise to clinical suspicion are very different, ranging from hematological to neurological-psychiatric up to gastrointestinal and less commonly to gynecological-obstetric symptoms or signs. Therefore, patients with autoimmune atrophic gastritis often seek advice from physicians of other medical specialties than gastroenterologists, thus underlining the need for increased awareness of this disease in a broad medical and scientific community.

Vitamin B12 and homocysteine in patients with major depressive disorder.

Background: Alterations in the level of neurotransmitters are evident in patients with major depressive disorder (MDD). Vitamin B12 mediates the synthesis of neurotransmitters, and hence, vitamin B12 deficiency could be associated with depression. Aims and Objectives: To assess the levels of serum vitamin B12, homocysteine (Hcy), and haematological profiles in patients of MDD. Materials and Methods: Fifty-nine patients with MDD were recruited based on ICD-10 criteria. Severity of depression was assessed by HAM-D scale. Vitamin B12, Hcy levels, and haematological profiles were analysed. Results: Vitamin B12 was deficient or depleted in all patients with MDD. The median level of vitamin B12 in serum was 164.2 pg./ml and significantly lower in patients with severe MDD. The mean value of Hcy was 18.34 µmol/L, which was high compared to the normal reference range. The red cell distribution width (RDW-CV) varied significantly between the three groups of MDD patients. Patients consuming non-vegetarian food had a significantly higher median value of serum vitamin B12. Conclusion: Vitamin B12 deficiency is found in patients with MDD and varies inversely with severity of MDD. Hcy is found to be higher in patients with MDD. The manifestation of depressive symptoms precedes the more commonly known haematological manifestations of vitamin B12 deficiency in this study.

Multidisciplinary rehabilitation following recreational nitrous oxide (N2O) misuse: evaluating service provision and rehabilitation outcomes in a cohort with serious disability.

Purpose: Recreational nitrous oxide (N2O) misuse is increasing globally. Chronic misuse can cause neurological impairments that require rehabilitation, though literature characterising rehabilitation is limited. This study aimed to evaluate rehabilitation service provision for impairments resulting from N2O misuse. Methods: A retrospective audit of hospitalised patients referred for rehabilitation for N2O toxicity was conducted between 2015 and 2022 at a single metropolitan hospital. Data were collected via medical record audit and analysed via descriptive and non-parametric statistics. Results: 16 eligible cases were identified, aged 18-43 years (50% female/male), with increasing case frequency. 12 cases received inpatient rehabilitation episodes for multifactorial sensorimotor, cognitive and psychosocial impairments. Cases articulated diverse rehabilitation goals and received intervention from a median of 6 clinical disciplines. All cases required assistance to mobilise or perform self-care activities on admission. Functional Independence Measure (FIM) scores significantly improved with rehabilitation (median FIM 84[75-93] to 117[112-123], p < .001). Despite gains in independence, all cases required referral for ongoing rehabilitation post-discharge. Conclusions: Demand for inpatient rehabilitation for disabling N2O toxicity appears to be increasing. In this series, cases were young, exhibited serious impairments, and had multidisciplinary rehabilitation needs. Inpatient rehabilitation led to significant functional improvements, though ongoing disability was evident post-discharge.

There appears to be rising demand for multidisciplinary rehabilitation to manage neurological disabilities from recreational Nitrous Oxide (N₂O) misuse.Heavy N₂O misuse can cause serious impairments and activity limitations across sensorimotor, cognitive and psychosocial domains.Intensive, multidisciplinary rehabilitation can improve functional independence for people with disabling N₂O toxicity; specialist rehabilitation services should be involved in optimising care of this population.Ongoing disability and the need for longer-term rehabilitation and support following hospital discharge were evident in severe cases of N₂O toxicity.

Vitamin B12-Related Biomarkers.

BACKGROUND: Adult vitamin B12 (B12) deficiency may present itself with nonspecific mainly neurological symptoms, and thus plasma biomarkers are often judged to be of major importance in the further diagnostic process. Four biomarkers are of special relevance: total B12, holotranscobalamin (the part of B12 bound to the active transport protein, transcobalamin, also named holoTC or active B12) and the 2 so-called metabolic markers that accumulate if B12 is lacking, methylmalonic acid (MMA) and homocysteine. OBJECTIVE: This article briefly reviews the inherent limitation of biomarkers, discusses its use in establishing the diagnosis and cause of B12 deficiency, and when following or discontinuing treatment with B12. METHODS: The review is based on published papers, but also on knowledge gained from working within the area. CONCLUSION: It is concluded that a combination of a B12 and a metabolic marker, for example, total B12 and MMA, may prove most useful in daily practice. An unexpectedly high level of total B12 is most often of no clinical importance, though sometimes related to the presence of underlying cancer. Measurement of total B12 is of limited value in patients on treatment with pharmacological doses of B12 but may be helpful if B12 treatment is discontinued.

Plain language titleVitamin B12-Related Blood TestsPlain language summaryBlood-testing is considered an important part of the diagnostic procedure in patients suspected to suffer from B12 deficiency. A deficiency is supported by a low level of plasma B12, and confirmed by a high level of methylmalonic acid, judged according to age and kidney function. Alternatively, a high level of homocysteine may support the diagnosis. Treatment of B12 deficiency is mainly guided by improvement of symptoms, with a very limited need for further blood testing. If B12-treatment is discontinued, B12 status should be judged every 6 months for approximately 2 years to detect a possible reoccurrence of a deficient state. An unexpected high level of plasma B12 is most often of no clinical implication.

Vitamin B12 Deficiency in Children and Adolescents: A Case for Revised Diagnostic Parameters.

BACKGROUND: Vitamin B12 deficiency is commonly diagnosed using thresholds developed for adults, yet emerging evidence indicates these levels may not be appropriate for children and adolescents. This misalignment can lead to underdiagnosis in younger populations, with potential long-term health implications. CASE SUMMARY: Chief Complaint: The 17-year-old female patient experienced severe fatigue, menstrual irregularities, psychological distress, and neurological symptoms over several years. The 13-year-old male patient had behavioral changes, gastrointestinal complaints, and sensory disturbances from an early age.Diagnosis: Both adolescents displayed B12 levels that were considered low-normal based on adult thresholds, complicating their diagnostic processes. Their diverse and atypical symptomatology required a comprehensive review of their medical and family histories, clinical symptoms, and risk factors.Intervention: Treatment included administration of hydroxocobalamin injections, complemented by dietary adjustments.Outcome: Both patients responded well to the treatment, showing significant improvements in their symptoms and overall quality of life. CONCLUSION: The main takeaway from these cases is the importance of tailoring diagnostic adequate thresholds and treatment plans to the pediatric population to address and manage B12 deficiency effectively. This approach can significantly enhance patient outcomes and prevent the progression of potentially severe complications in later life.

Plain language titleRevisiting Diagnostic Criteria for Vitamin B12 Deficiency in Children and Adolescents, a Case ReportPlain language summaryVitamin B12 deficiency is surprisingly common in kids and teenagers, but the problem is, only adult standards are available to diagnose it. Research shows that healthy children can have much different B12 levels than adults, meaning some kids with a deficiency might not get the help they need quickly. We share stories of 2 teenagers who suffered from B12 deficiency with very different symptoms, from extreme tiredness to mood changes and stomach issues. These cases show that diagnosing B12 deficiency can be difficult, especially with symptoms that don't fit the usual pattern. However, once they were properly diagnosed and treated adequate, these young people saw significant improvements in their health. These cases highlight the need for new standards tailored to children, to better identify and treat B12 deficiency early on, improving their quality of life.

Vitamin B12 Deficiency-Induced Neuropathy and Cognitive and Motor Impairment in the Elderly: A Case Study.

Vitamin B12 deficiency can present with a variety of neurological and cognitive symptoms. Especially in elderly patients, vitamin B12 deficiency can be easily overlooked because symptoms may be attributed to comorbid conditions or solely to the aging process. In this case study, we present two patients, a 71-year-old man and a 74-year-old female, with vitamin B12 deficiency. The male patient had a history of (partial) resection of the ileum/jejunum/colon because of intestinal ischemia. The female patient had a history of hypothyroidism, type 2 diabetes with complications (including peripheral neuropathy), mitochondrial myopathy, and chronic lymphocytic leukemia. Both patients presented with severe fatigue, cognitive impairment, and impaired walking. Next to this, the male patient suffered from depressive symptoms and mild disorientation, and the female patient experienced neuropathic pain. She also mentioned a positive family history for B12 deficiency. The first patient had normal to high B12 levels because he was already on B12 injections (once every three weeks) because of an earlier diagnosed B12 deficiency. The female patient had B12 levels within normal range (holotranscobalamin 54 pmol/L) and her diagnosis was confirmed by elevated homocysteine and methylmalonic acid levels. Treatment with frequent hydroxocobalamin injections and other supplements significantly improved their cognitive, emotional, and motor functions. These cases underscore the need for a high level of clinical suspicion in elderly patients, also in cases of normal B12 levels but with clinical signs of deficiency and a positive risk factor, such as stomach or small bowel surgery or positive family history.

Plain language titleA case study of two elderly patients with vitamin B12 deficiency and neurological and cognitive complaintsPlain language summaryVitamin B12 deficiency in elderly patients can be easily overlooked as symptoms can also be caused by other age-related diseases or the aging process. In our article we present two elderly patients, a 71-year-old male and a 74-year-old female, with neurological complaints, such as severe fatigue, cognitive decline, and walking impairment. The male patient had a history of small bowel surgery, and the female patient mentioned that she had several siblings with B12 deficiency. Additionally, the male patient suffered from depressive symptoms and mild disorientation, and the female had severe pain in her legs. The male patient already received B12 injections because of an earlier B12 diagnosis, but with a relatively low frequency. The B12 levels of the female patients were within the normal range. However, her diagnoses could be confirmed with additional laboratory measurements, such as homocysteine and methylmalonic acid. Treatment with frequent B12 injections and other supplements significantly improved their cognitive, emotional, and motor functions. Our study shows that clinicians should carefully consider the possibility of B12 deficiency in elderly patients with cognitive and neurological complaints, also in patients with B12 levels within the normal range, but with risk factors such as family members with B12 deficiency or conditions that may impair the vitamin B12 uptake, such as previous stomach or small bowel surgery.

Lack of Clinical Evidence Regarding the Guidelines for Vitamin B12 Deficiency: An Analysis From Literature and Recommendations From Clinical Practice.

BACKGROUND: Vitamin B12 deficiency is a critical medical condition that, if left untreated, can lead to severe symptoms and potentially serious and life-threatening complications. Clinical guidelines are designed to provide a standardized approach to diagnosis and treatment, aiming for consistency and effectiveness. However, it is well-established that not all patients fit into general guidelines. OBJECTIVE: To investigate the clinical relevance of the submitted research to support these protocols for diagnosing and treating a B12 deficiency. APPROACH: Conducting a literature review of the references focused and used on diagnosing and treating vitamin B12 deficiency in adults and children. RESULTS: No robust clinical trial nor RCT has been found to back up the current protocols. The research used is primarily based on assumptions rather than solid clinical evidence. CONCLUSION: Existing guidelines for vitamin B12 deficiency need to be significantly revised and improved through clinical research, clinical experience by experts in the field with input from patient groups worldwide.

Plain language titleAnalyzing the Lack of Research on Vitamin B12 Deficiency Guidelines: Insights from Studies and Clinical AdvicePlain language summaryThis study dives into Vitamin B12 deficiency, stressing its serious health impacts and potential life-threatening complications when not treated. The study aims to investigate the scientific articles supporting these guidelines and their clinical relevance, conducting an in-depth analysis of literature references. The manuscript investigates and criticizes current guidelines for B12 deficiency, pointing out 4 key issues reported by patients and clinicians worldwide. The results are grouped into 4 sections: Maintenance Dose Protocol: The study questions the adequacy of maintenance doses every few months, highlighting a lack of clinical evidence and challenging the idea of sufficient liver stores. Oral Supplementation Protocol: The effectiveness of oral supplements is questioned due to inconclusive trials, focusing on raising blood values rather than assessing actual clinical outcomes. Diagnosing B12 Deficiency in Children: Guidelines neglect B12 deficiency in children despite significant differences in B12 levels between adults and healthy kids, potentially leading to underdiagnosis and unnecessary suffering. Delay in Diagnosis and Treatment: Factors like a lack of awareness and diverse symptoms contribute to delays, emphasizing the ongoing challenge of standardizing B12 assays. In the discussion, the manuscript argues that awareness of guidelines is low, and evidence-based guidelines may lack practical relevance. It suggests a significant revision of guidelines based on robust clinical evidence, advocating for personalized treatment, patient monitoring tools, controlled trials, and age-related healthy levels. Recognizing diverse patient needs and implementing individualized therapies are crucial for improving care for those with vitamin B12 deficiency, emphasizing the importance of early recognition and intervention.

Development of a Vitamin B12 Deficiency Patient-Reported Outcome Measure for Clinical Practice and Research.

BACKGROUND: It is difficult to recognize vitamin B12 deficiency and to evaluate the effect of B12 treatment due to a broad range of variable clinical symptoms overlapping with other diseases and diagnostic biomarkers that quickly normalize during treatment. This poses a risk of delay in diagnosis and a challenge to uniformly monitor the effect of B12 treatment. There is a need for a new clinical outcome measure suitable for clinical practice and clinical evaluation studies. OBJECTIVE: To develop a Patient-Reported Outcome Measure (PROM) which measures the severity of vitamin B12 deficiency symptoms. METHODS: The B12 PROM was developed by (1) gathering input from experts and literature review to define a construct and develop a conceptual model, (2) processing input from health care providers, scientists, and patients to develop items and response options, and (3) improving items based on the feedback from laypersons, test interviews, semi-structured cognitive interviews with patients, and forward and backward translation (ENG-NL). RESULTS: The B12 PROM includes 62 items grouped into 8 categories of symptoms related to vitamin B12 deficiency (General, Senses, Thinking, In limbs and/or face, Movement, Emotions, Mouth & Abdomen, Urinary tract & Reproductive organs). Cognitive interviews demonstrated good comprehensibility and comprehensiveness. CONCLUSIONS: This study is the first step in the development of a disease-specific PROM for vitamin B12 deficiency to measure the burden of symptoms. Further validation and reliability testing are necessary before the PROM can be applied in clinical practice and research.

Plain language titleDevelopment of a Vitamin B12 Deficiency Questionnaire for Clinical Practice and ResearchPlain language summaryThis study is the first step in the development of a questionnaire for vitamin B12 deficiency to measure the severity of vitamin B12 deficiency symptoms. The questionnaire includes 62 items grouped into 8 categories of symptoms related to vitamin B12 deficiency (General, Senses, Thinking, In limbs and/or face, Movement, Emotions, Mouth & Abdomen, Urinary tract & Reproductive organs). Interviews with patients demonstrated good comprehensibility and comprehensiveness of the questionnaire. Further testing is necessary before the questionnaire can be applied in clinical practice and research.

Causes and Risk Factors of Vitamin B12 Deficiency at the Bookends of Life, From Infancy to Old Age.

The causes and risk factors of vitamin B12 deficiency are many and varied. Importantly, they vary considerably across the lifespan, from infancy to old age. The complexity of the physiology of vitamin B12 bespeaks the myriad of possible causes of deficiency and possible disruptions of its functional integrity. These lead ultimately to the pathobiological effects witnessed in deficiency of this fascinating micronutrient. This brief overview of the multiplicity of mechanisms that can result in vitamin B12 deficiency, and the panoply of its manifestations explores the underlying reasons for the protean presentations of the disease. As the human organism progresses through the chronology and milestones of age, various susceptibility factors arise resulting from the interplay of environmental and genetic factors. Acting independently and in concert, these factors produce the common denominator of vitamin B12 deficiency. However, the rate at which such deficiency develops and the way in which it presents clinically vary widely, subject to such influences as genetic variability, end-organ susceptibility, and concomitant micronutrient status. Some examples of unusual cases of vitamin B12 deficiency are described. Much has been learned about the last of the numbered vitamins in almost a century. Much yet remains to be discovered.

A Brief Overview of the Diagnosis and Treatment of Cobalamin (B12) Deficiency.

BACKGROUND: An increasing number of adult individuals are at risk of vitamin B12 deficiency, either from reduced nutritional intake or impaired gastrointestinal B12 absorption. OBJECTIVE: This study aims to review the current best practices for the diagnosis and treatment of individuals with vitamin B12 deficiency. METHODS: A narrative literature review of the diagnosis and treatment of vitamin B12 deficiency. RESULTS: Prevention and early treatment of B12 deficiency is essential to avoid irreversible neurological consequences. Diagnosis is often difficult due to diverse symptoms, marked differences in diagnostic assays' performance and the unreliability of second-line biomarkers, including holo-transcobalamin, methylmalonic acid and total homocysteine. Reduced dietary intake of B12 requires oral supplementation. In B12 malabsorption, oral supplementation is likely insufficient, and parenteral (i.e. intramuscular) supplementation is preferred. There is no consensus on the optimal long-term management of B12 deficiency with intramuscular therapy. According to the British National Formulary guidelines, many individuals with B12 deficiency due to malabsorption can be managed with 1000 µg intramuscular hydroxocobalamin once every two months after the initial loading. Long-term B12 supplementation is effective and safe, but responses to treatment may vary considerably. Clinical and patient experience strongly suggests that up to 50% of individuals require individualized injection regimens with more frequent administration, ranging from daily or twice weekly to every 2-4 weeks, to remain symptom-free and maintain a normal quality of life. 'Titration' of injection frequency based on measuring biomarkers such as serum B12 or MMA should not be practiced. There is currently no evidence to support that oral/sublingual supplementation can safely and effectively replace injections. CONCLUSIONS: This study highlights the interindividual differences in symptomatology and treatment of people with B12 deficiency. Treatment follows an individualized approach, based on the cause of the deficiency, and tailored to help someone to become and remain symptom-free.

Plain language titleDiagnosis and Treatment of Vitamin B12 DeficiencyPlain language summaryThe number of people who are at risk of developing a deficiency of vitamin B12 is steadily increasing. B12 deficiency can develop when people consume too few B12-containing foods of animal origin, or when they develop a form of B12 malabsorption. B12 deficiency can lead to serious complications so prevention and early treatment are essential. Diagnosing B12 deficiency can be challenging: the symptoms vary from patient to patient, and the methods used to measure B12 in the blood, or certain biomarkers associated with B12 metabolism, such as holo-transcobalamin, methylmalonic acid, and total homocysteine are unreliable. When people do not consume enough B12-containing foods, supplementation with B12 tablets is needed. In the case of B12 malabsorption, intramuscular injections of B12 are mandatory. The usual treatment with B12 is starting with injections of 1000 µg hydroxocobalamin twice weekly or on every other day for a period of up to 5 weeks or longer, until all symptoms have disappeared, and thereafter, the frequency of injections is gradually reduced. There is, however, a large group of people who require more frequent administration to become and remain symptom-free: this may range from daily or twice weekly to every 2 to 4 weeks.

Vitamin B12 and Age-Related Cognitive Decline-Dementia and "Alzheimer's Disease".

This article is a commentary on the role of vitamin B12 in age-related cognitive decline, with a meta-commentary on the misuse of the term "Alzheimer's Disease." The article describes the historical origins of the term "Alzheimer's Disease" and argues that the term should be restricted to a narrower segment of the age-related dementia spectrum. The article also outlines the role of vitamin B12 in age-related cognitive decline and outlines the rationale for the treatment of B12 deficiency to address a potentially reversible factor in cognitive decline.

Nitrous oxide abuse in a 21-year-old female: a case report and review of literature.

The abuse of nitrous oxide (N2O) poses a substantial public health challenge. In many countries, including China, regulations governing the utilization and accessibility to N2O remain ambiguous, particularly within the food industry. Here, we report a case of a 21-year-old female who presented with symptoms of subacute combined degeneration (SCD) of the spinal cord due to N2O abuse. The patient exhibited bilateral lower limb numbness and weakness, low serum vitamin B12 levels with elevated homocysteine levels, and lumbar spine magnetic resonance imaging (MRI) revealed abnormal signals of the spinal cord. Following cessation of N2O and comprehensive therapy including methylcobalamin and nerve growth factor, the symptoms significantly improved. A follow-up examination 3 months later showed good progress in gait stability. At a 5-year follow-up, the patient's previous clinical symptoms had completely disappeared, and her quality of life had returned to normal. This case underscores the urgency of raising awareness and prevention of N2O abuse, emphasizing the importance of timely diagnosis and comprehensive treatment for patient recovery. Clear formulation and enforcement of relevant regulatory measures are equally crucial in reducing instances of abuse.

Defining Optimal Cobalamin Status for Neonates and Infants.

BACKGROUND: An optimal cobalamin status is necessary for normal neurodevelopment. OBJECTIVE: To give a description of the epidemiology, pathophysiology and diagnostic challenges related to cobalamin insufficiency in neonates and infants in order to prevent its occurence. RESULTS: Inadequate cobalamin status is prevalent among neonates and young infants, due to a high prevalence of maternal cobalamin deficiency, exclusive breastfeeding for extended periods and late introduction of animal food. Cobalamin insufficiency is associated with delayed neurodevelopment and subtle clinical symptoms like feeding difficulties, regurgitations and constipation in young infants. Early diagnosis and treatment of impaired cobalamin status is important to prevent neurologic damage. CONCLUSION: Clinical suspicion of cobalamin insufficiency in infants should infer immediate biochemical testing and a plasma total homocysteine > 5.0 µmol/L indicate cobalamin insufficiency in need of intramuscular treatment with hydroxycobalamin, followed by introduction of animal food after 4 months of age.

Plain language titleVitamin B12 Is Important for Normal Development in Young ChildrenPlain language summaryVitamin B12, also called cobalamin, is found only in animal-sourced food. As low-meat, vegetarian, and vegan diets are increasingly popular in Western countries, vitamin B12 deficiency has become common, also in pregnant women and babies. Vitamin B12 status is essential for normal development and adequate levels of this vitamin is particularly important during pregnancy and the first years of life. In pregnancy, vitamin B12 is transferred from the mother to the fetus, so the baby has a store of this vitamin at birth. However, if the mother has vitamin B12 deficiency or the baby is born premature or with a low birth weight, the vitamin store may be insufficient and the baby may develop vitamin B12 deficiency. Maternal vitamin B12 status is important as long as the baby is exclusively breastfed. Breast milk contains vitamin B12, but the concentration decreases after 4 to 6 weeks and may be too low to support the baby until animal-sourced foods are introduced. The vitamin B12 content in formula milk is higher than in breast milk, and vitamin B12 deficiency is more common in exclusively breastfed babies. Vitamin B12 deficiency is associated with diffuse symptoms in small babies and may be difficult to detect, and the diagnosis have a mean delay of 4 months in this age-group. Typical symptoms are regurgitations or spitting up, constipation, problems with feeding and swallowing, and delayed psychomotor development. Suspicion of vitamin B12 insufficiency in babies should prompt immediate biochemical testing. Plasma total homocysteine is a metabolic marker of vitamin B12 status and can be measured in a blood sample from the baby. A level >5.0 µmol/L indicates probable vitamin B12 insufficiency and the baby should receive vitamin B12 supplementation, followed by introduction of animal-sourced foods at 3 to 4 months of age.

A Systematic Review of Symptoms of Pernicious Anemia.

BACKGROUND: Pernicious anemia (PA) is a type of macrocytic anemia caused by autoimmune gastritis. To facilitate timely diagnosis and treatment of PA there is a pressing need for improved understanding among Healthcare providers of the condition's symptoms and diagnostic criteria. OBJECTIVE: This systematic review aims to extend existing clinical knowledge on the presentation of PA by determining which symptoms and clinical complications are reported in published adult case studies. METHODS: Relevant studies were identified through electronic searches of PsycINFO, Embase, and MEDLINE, via OvidSP. During data extraction symptoms were categorized according to the International Classification of Diseases and were grouped based on frequency. RESULTS: Symptoms were documented for 103 adults with a diagnosis of PA; the most frequent symptoms were fatigue (55%), loss of sensation in limbs (32%), excessive weight loss (27%), and a sore tongue (23%). CONCLUSIONS: This review highlights the diverse symptomology of adults who are diagnosed with PA. Most symptoms documented in case studies are consistent with the core signs of B12 and folate deficiencies. Research is needed to identify if there are common clusters of PA symptoms that can be used as prompts for diagnostic testing in patients with suspected B12 deficiency.

Plain language titleA Review of Symptoms of Pernicious AnemiaPlain language summaryThis study reviewed case studies that have been written about adults with pernicious anemia, it has documented the frequency of the core symptoms and the impact these have on health.