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Vitamin B12

Cobalamin · Cyanocobalamin · Methylcobalamin · B12

Vitamine & Nährstoffe
Einheit:
pmol/L
Abbreviation
B12

The test quantifies the concentration of vitamin B12 in the blood, reflecting its availability for biological processes.

Reference Ranges

Reference
148740pmol/L
148
300
600
740
LowNormalHigh
Reference
Optimal
Unit · pmol/L

Ranges may vary slightly by laboratory; age and dietary habits can influence levels.

Overview

Übersicht

Vitamin B12, also known as cobalamin, is a water-soluble vitamin essential for various biological processes, including DNA synthesis, red blood cell formation, and nervous system function. It is unique among vitamins due to its complex absorption pathway, which requires intact gastric and terminal small intestinal function, and its role as a cofactor in only two enzymatic reactions in humans: the cytosolic methionine synthase reaction and the mitochondrial methylmalonyl CoA mutase reaction. Clinically, vitamin B12 deficiency can lead to megaloblastic anemia, characterized by ineffective red blood cell production, and neurological disorders due to defective myelin synthesis. It is particularly prevalent in the elderly and in populations with limited dietary intake or malabsorptive disorders. In athletes and biohackers, maintaining optimal B12 levels is crucial for energy metabolism and cognitive function, potentially enhancing performance and longevity. However, researchers have observed that B12 levels can be influenced by factors such as dietary intake, genetic predispositions, and gut microbiota balance, which may confound test results. Therefore, careful consideration of these factors is necessary when interpreting B12 levels.

Klinische Bedeutung

Reduced vitamin B12 levels indicate potential deficiency, leading to megaloblastic anemia and neurological disorders. Elevated levels are less common and may indicate liver disease or excessive supplementation.

Dynamics

Trend Interpretation

Rising Values

Progressively rising B12 levels may indicate excessive supplementation or liver dysfunction. Re-test in 3 months if levels exceed optimal range.

Falling Values

Falling B12 levels suggest potential malabsorption or dietary insufficiency.

Re-test Interval

4 weeks if outside optimal range

Etiology

Causes — High & Low

Cause

Elevated Levels

  • Liver disease
  • Excessive supplementation
  • Leukemia
  • Renal failure
  • Polycythemia vera
Cause

Low Levels

  • Malabsorption syndromes
  • Pernicious anemia
  • Vegan diet
  • Gastrointestinal surgery
  • Helicobacter pylori infection
Protocol

How to Optimize

Lever

Lifestyle

  • Regular monitoring of levels
  • Addressing gut health
  • Avoiding excessive alcohol consumption
Lever

Nutrition

  • Incorporating animal products
  • Fortified cereals
  • Nutritional yeast
Lever

Supplementation

  • Cyanocobalamin
  • Methylcobalamin
  • Hydroxocobalamin

Note:

Consult a healthcare provider before starting supplementation, especially if you have underlying health conditions.

Testing Guidelines

Fasting Not Required
Not Time-Sensitive

Testing Frequency

Annually for adults, more frequently if symptomatic or at risk.

Interfering Factors

  • Recent vitamin supplementation
  • Liver disease
  • Renal disease

Related Peptides & Hormones

Homocysteine

Correlated with

hormone or peptide

Open Research Questions

Current research suggests that the relationship between vitamin B12 levels and conditions like Autism Spectrum Disorder remains inconclusive, with inconsistent findings across studies and a lack of longitudinal data to account for individual variability. Researchers have not yet established optimal reference ranges or targets for B12 levels in various populations, particularly in pregnant women and children. Additionally, clinical questions remain unanswered regarding the specific mechanisms by which B12 deficiency influences neurodevelopment and cognitive outcomes.

20 Research Publications

675

Total Citations

2

Human/RCT

3.0

Avg. Influence

2025

Latest

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Filter
#01

How I treat anemia in pregnancy: iron, cobalamin, and folate.

ReviewInfluence7.0
172
This study discussed anemia in pregnancy, identifying vitamin B12 deficiency as a rising concern due to increased obesity and bariatric surgery rates. Researchers highlighted the importance of diagnosing and treating vitamin B12 deficiency to prevent adverse outcomes for both mother and fetus. The article reviewed various clinical cases and management strategies.
View on PubMed
#02

Vitamin B12 status in health and disease: a critical review. Diagnosis of deficiency and insufficiency - clinical and laboratory pitfalls.

ReviewInfluence5.0
148
This critical review focused on vitamin B12's role in health and disease, discussing its complex metabolic pathways and the challenges in diagnosing deficiency. Researchers found that vitamin B12 deficiency can present with various symptoms and may be misdiagnosed due to the limitations of standard tests. Increased awareness and improved testing methods are necessary.
View on PubMed
#03

Severe megaloblastic anemia: Vitamin deficiency and other causes.

ReviewInfluence5.0
96
Researchers found that megaloblastic anemia, characterized by macrocytic anemia, is commonly caused by vitamin B12 and folate deficiencies. The study emphasized the importance of diagnosing megaloblastic anemia through specific laboratory findings while considering other potential causes. Treatment typically involves addressing the underlying deficiency.
View on PubMed
#04

Laboratory testing for cobalamin deficiency in megaloblastic anemia.

ReviewInfluence2.0
71
This study focused on laboratory testing for cobalamin deficiency in megaloblastic anemia. Researchers found that traditional serum cobalamin tests may not accurately reflect vitamin B12 status, suggesting the need for alternative biomarkers to improve diagnostic accuracy.
View on PubMed
#05

Omeprazole and vitamin B12 deficiency.

ReviewInfluence1.0
45
Researchers observed that omeprazole therapy can decrease the absorption of vitamin B12, potentially leading to deficiency. The study highlighted the need for further clinical trials to assess the long-term significance of this interaction and the importance of monitoring vitamin B12 levels in patients on chronic omeprazole treatment.
View on PubMed
#06

Vitamin B12 deficiency and metabolism-mediated thrombotic microangiopathy (MM-TMA).

ReviewInfluence2.0
38
Researchers examined the relationship between vitamin B12 deficiency and thrombotic microangiopathy (TMA). They found that severe B12 deficiency can mimic TMA symptoms, highlighting the importance of prompt identification and treatment of B12 deficiency.
View on PubMed
#07

Vitamin B12 deficiency.

ReviewInfluence1.0
37
This study examined vitamin B12 deficiency, highlighting its complex absorption pathway and various causes, including malabsorption and limited dietary intake. Researchers found that B12 deficiency can affect multiple organ systems, particularly the blood and nervous system, leading to conditions such as megaloblastic anemia and cognitive impairment. Diagnosis relies on clinical suspicion and laboratory testing.
View on PubMed
#08

[Vitamin B12 (cobalamin)].

ReviewInfluence2.0
29
This study reviewed the clinical significance of vitamin B12 deficiency, highlighting its association with megaloblastic anemia and neurological disorders. Researchers discussed the biochemical parameters used to diagnose both clinical and subclinical deficiency.
View on PubMed
#09

The application and interpretation of laboratory biomarkers for the evaluation of vitamin B12 status.

Harrington Dominic J, et al. · Annals of clinical biochemistry · 2025

ReviewInfluence2.0
19
Researchers examined the biomarkers used to evaluate vitamin B12 status, noting that deficiency can lead to serious health issues. The study emphasized the limitations of current diagnostic tests and the need for a comprehensive approach to assess B12 status accurately. The use of multiple biomarkers may improve detection of deficiency.

Key findings

  1. 01Researchers observed that different biomarkers can indicate vitamin B12 deficiency or sufficiency.
  2. 02The review identified the significance of accurate interpretation of test results for proper health assessments.
  3. 03Researchers noted that understanding these biomarkers is crucial for preventing potential health issues related to vitamin B12 status.
View on PubMed
#10

Vitamin B12 and Autism Spectrum Disorder: A Review of Current Evidence.

Review
11
Researchers reviewed the role of vitamin B12 in neurodevelopment, particularly its importance during pregnancy and early childhood. The study found that inadequate maternal B12 levels may influence fetal brain development and increase the risk of autism spectrum disorder (ASD). The link between B12 levels and ASD remains inconclusive, with calls for further research.
View on PubMed

Publication Trend

Research publications about Vitamin B12 over time

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