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B127.5
Vitamin B12 – Forschung
Hilft vermutlich
87 begutachtete Studien
Was die Evidenz sagt
Hilft wahrscheinlich
Vitamin B12 scheint in 18 von 25 Studien mit messbaren Effekten zu helfen — die Evidenz tendiert klar ins Positive.
Die meiste Evidenz stammt aus hochwertigen Meta-Analysen und randomisierten Studien, veröffentlicht 2006–2026 mit einer typischen Studiengröße von 612 Teilnehmenden.
Basierend auf 87 Studien · 29 Meta-Analysen · 20 RCTs · 515,880 Teilnehmende insgesamt
Konfidenz
Hohe Konfidenz
Was die Studien gefunden haben
18geholfen2unklar5nicht geholfen· 62 weitere ohne bewertete Effektdaten
Nach Outcome
B12 deficiency & anemia
Hilft wahrscheinlich67 Studien
Therapeutic & clinical
Hilft vermutlich22 Studien
Heart & blood pressure
Hilft wahrscheinlich16 Studien
Cognitive functionMethylierungsunterstützung, essenziell für die Neurotransmittersynthese und das Gedächtnis · 4-8 Wochen
Hilft wahrscheinlich15 Studien
Women's healthUnterstützt einen gesunden Östrogenstoffwechsel und das hormonelle Gleichgewicht · 4-8 Wochen · Entscheidend für die Prävention von Neuralrohrdefekten zusammen mit Folat · Fortlaufend
Hilft vermutlich12 Studien
Glucose & metabolic
Hilft vermutlich10 Studien
Safety profile
Hilft wahrscheinlich9 Studien
Neuroprotection & brain agingUnterstützt die Erhaltung des Myelins; ein Mangel führt zu neurologischen Schäden · Fortlaufend
Überwiegend Mechanismus / Beobachtung7 Studien
ALS & motor-neuron disease
Zu wenige bewertete Studien2 Studien
Depression & moodDie Korrektur eines Mangels verbessert Depressionen und kognitiven Nebel · 4-8 Wochen
Zu wenige bewertete Studien2 Studien
Bone healthUnterstützt die Knochenmineraldichte und die Festigkeit des Skeletts · 8-12 Wochen
Zu wenige bewertete Studien2 Studien
Energy & fatigueWiederhergestellte Energie bei Mangel; moderater Nutzen bei ausreichender Versorgung · 2-4 Wochen
Zu wenige bewertete Studien1 Studie
Immune support
Zu wenige bewertete Studien1 Studie
Anxiety & stress
Zu wenige bewertete Studien1 Studie
In Zahlen
Aus 64 Studien mit messbaren Effekten gezogen
Wahrscheinlich echte Effekte
85%
über Studien hinweg
Untersuchte Personen
516k
typische Studie: 612 Personen
Stärkste Designs
49
29 gepoolt, 20 randomisiert
Zeigte Nutzen
72%
18/25 Studien
Wie lange Studien liefen
1–3 Monate
3
3+ Monate
8
Untersuchte Populationen
Pregnant women6
Type 2 diabetes mellitus patients2
adults at cardiovascular risk1
Adults in areas without/with partial folic acid fortification1
Aktives Forschungsgebiet
79 Studien in den letzten 5 Jahren · Neueste Meta-Analyse: 2026
200620162026
1Meta-Analysen=48,626 · very large study2026
These findings underscore the need for careful dietary planning and supplementation in lacto-ovo-vegetarian and vegan children.
Lotti S, Panizza G, Martini D, Marx W, Beasley JM, Colombini B, Dinu M. · Critical reviews in food science and nutrition (2026)
Biomarkers showed lower ferritin and 25(OH)D in lacto-ovo-vegetarians, and lower hemoglobin and ferritin in vegans.
Although group averages for most nutrients and biomarkers remained within pediatric reference ranges, increased odds of iron deficiency and anemia were observed in lacto-ovo-vegetarians, and vitamin B12 deficiency in vegans.
Both groups showed lower total and LDL cholesterol.
2major adverse cardiovascular eventsMeta-Analysen=68,363 · very large study2026
Overall, B-vitamin combinations do not confer consistent benefit for major cardiovascular outcomes but may reduce stroke and MACE in selected primary prevention populations, suggesting that baseline cardiovascular risk and regional folic acid fortification modify treatment effects and should guide future trial design and clinical use.
Ren R et al. · Nutrients (2026)
Kein klarer Effekt
← SchlechterKein EffektBesser →
Random-effects models were used in this meta-analysis to calculate pooled risk ratios (RRs) and 95% confidence intervals (CIs).
B-vitamin combinations were associated with a nonsignificant reduction in stroke and 3-point major adverse cardiovascular events (MACE) (stroke: RR 0.91, 95% CI 0.81-1.04; MACE: RR 0.93, 95% CI 0.86-1.01).
No significant effects were observed for all-cause mortality (RR 1.01, 95% CI 0.96-1.06), cardiovascular mortality (RR 0.97, 95% CI 0.88-1.07), or MI (RR 0.97, 95% CI 0.91-1.03).
3Stroke risk reductionMeta-AnalyseCited 12×n=76,664 · very large study2024
Our meta-analysis found that the folic acid combined with vitamin B12 and vitamin B6 supplementation strategy significantly reduced the risk of stroke in areas without and with partial folic acid fortification.
Zhang N et al. · The American journal of clinical nutrition (2024)
Groß Nutzen
← SchlechterKein EffektBesser →
In areas without and with partial folic acid fortification, combined B-vitamin supplementation significantly reduced the risk of stroke by 34% [RR: 0.66; 95% confidence interval (CI): 0.50, 0.86] and 11% (RR: 0.89; 95% CI: 0.79, 1.00), respectively.
Further analysis showed that a dosage of folic acid ≤0.8 mg/d and vitamin B12 ≤0.4 mg/d was best for stroke prevention (RR: 0.65; 95% CI: 0.48, 0.86) in these areas.
In contrast, no benefit of combined supplementation was found in fortified areas (RR: 1.04; 95% CI: 0.94, 1.16).
4Serum iron levelsMeta-AnalyseCited 3×n=8,542 · very large study2024
Patients with vitiligo should reduce smoking and alcohol consumption and take appropriate vitamin E, B12, copper, and zinc supplements.
Liang X et al. · Frontiers in immunology (2024)
Spürbar Nutzen
← SchlechterKein EffektBesser →
Vitamin C [mean difference (MD), -0.342; 95% confidence interval (CI), -1.090-0.407; p >0.05), folic acid (MD, -1.463; 95% CI, -7.133-4.208; p >0.05), and selenium (MD, 0.350; 95% CI, -0.687-1.387; p >0.05) levels did not differ between the groups.
The serum iron level of the vitiligo group was significantly higher than that of the control group (MD, 1.181; 95% CI, 0.390-1.972; p <0.005).
Patients with vitiligo should reduce smoking and alcohol consumption and take appropriate vitamin E, B12, copper, and zinc supplements.
6Vitamin B12 level increaseMeta-AnalyseCited 19×n=4,275 · very large study2024
All IM, oral, and SL routes of administration of vitamin B12 can effectively increase the level of vitamin B12 without significant differences between them, as thought previously.
Abdelwahab OA et al. · Irish journal of medical science (2024)
Regarding the hemoglobin level, the pooled effect sizes showed no difference between all routes of administration that could reach statistical significance.
However, the IM route was the top-ranked statistically but without clinical significance.
We found no significant difference among studied administrated routes in all other CBC parameters and homocysteine levels.
7Vitamin B12 deficiency riskMeta-AnalyseCited 25×n=2,852 · very large study2023
Although the pooled OR of vitamin B12 deficiency was slightly increased in PPI users, but there was significant heterogeneity, and the pooled OR was too low to imply an association clearly.
Choudhury A et al. · Expert review of gastroenterology & hepatology (2023)
Groß Schaden
← SchlechterKein EffektBesser →
The pooled OR of vitamin B12 deficiency among PPI users (2852 participants) was higher than non-users (28070 participants) (OR 1.42, 95% CI: 1.16-1.73; I2 = 54%).
Overall risk of PPI use among vitamin B12 deficient individuals was higher than those without deficiency (OR 1.49, 1.20-1.85; I2 = 68%).
Although the pooled OR of vitamin B12 deficiency was slightly increased in PPI users, but there was significant heterogeneity, and the pooled OR was too low to imply an association clearly.
8Vitamin B12 levels in hypothyroidism vs healthy controlsMeta-AnalyseCited 22×n=28,597 · very large study2023
Patients with hypothyroidism had lower levels of vitamin B12 than healthy participants.
Benites-Zapata VA et al. · Frontiers in endocrinology (2023)
Spürbar Nutzen
← SchlechterKein EffektBesser →
Likely real
We found that patients with hypothyroidism had lower vitamin B12 levels than healthy participants (MD: -60.67 pg/mL; 95% CI: -107.31 to -14.03 pg/mL; p = 0.01).
No significant differences in vitamin B12 levels were observed between healthy participants and patients with hyperthyroidism (p = 0.78), autoimmune thyroid disease (AITD) (p = 0.22), or subclinical hypothyroidism (SH) (p = 0.79).
The frequencies of vitamin B12 deficiency among patients with hypothyroidism, hyperthyroidism, SH, and AITD were 27%, 6%, 27%, and 18%, respectively.
11Cognitive decline preventionMeta-AnalyseCited 100×n=46,175 · very large study2022
This meta-analysis suggests that B vitamin supplementation is associated with slowing of cognitive decline, especially in populations who received early intervention and intervention of long duration; the study also indicates that higher intake of dietary folate, but not B12 or B6, is associated with a reduced risk of incident dementia in non-dementia aged population.
Wang Z et al. · Nutrition reviews (2022)
Spürbar Nutzen
← SchlechterKein EffektBesser →
In the non-dementia population, B vitamin supplementation slowed cognitive decline (3431 participants; MD, 0.15, 95%CI 0.04 to 0.25) compared to placebo; this outcome was not found for the dementia population (642 participants; MD, 0.20, 95%CI -0.35 to 0.75).
Given the prevalence of dementia cases in many countries with aging populations, public health policies should be introduced to ensure that subgroups of the population at risk have an adequate B vitamin status.
12Folate levelsMeta-AnalyseCited 12×n=770 · large study2024
Our study provides valuable insights into the nutritional status of PKU patients, but further research is required to confirm these findings and explore additional factors influencing vitamin status in PKU.
Bokayeva K et al. · International journal of molecular sciences (2024)
Sehr groß Nutzen
← SchlechterKein EffektBesser →
Likely real
The effect sizes were expressed as standardised mean differences.
The calculation of effect sizes with 95% CI using fixed-effects models and random-effects models was performed.
A p-value < 0.05 was considered statistically significant.
13Cognitive function improvementMeta-AnalyseCited 65×n=6,276 · very large study2021
Vitamin B12 supplementation is likely ineffective for improving cognitive function and depressive symptoms in patients without advanced neurological disorders.
Markun S et al. · Nutrients (2021)
Further, meta-regression showed no significant associations of treatment effects with any of the potential predictors.
We also found no overall effect of vitamin supplementation on measures of depression.
Further, only one study reported effects on idiopathic fatigue, and therefore, no analysis was possible.
16Glycemic control in T2DM with peripheral neuropathyMeta-AnalyseCited 1×2025
Dapagliflozin combined with methylcobalamin appears to be an effective and safe therapeutic strategy for managing DPN in T2DM patients, improving both nerve function and glycemic control.
Deng XL et al. · Frontiers in endocrinology (2025)
Glycemic control also improved, with reductions in FPG (MD, 95% CI: -1.19 mmol/L [-1.40, -0.98]; P<0.01), 2hPG (MD, 95% CI: -1.36 mmol/L[-1.44, -1.27]; P<0.01), and HbA1c levels (MD, 95% CI: -0.87% [-1.04, -0.71]; P<0.01).
There was no significant increase in adverse events (OR: 0.37; 95% CI: 0.07-2.03; P=0.25).
Dapagliflozin combined with methylcobalamin appears to be an effective and safe therapeutic strategy for managing DPN in T2DM patients, improving both nerve function and glycemic control.
17Neuropathy symptom improvementMeta-AnalyseCited 49×n=46 · small study2021
PN is associated with lowered plasma vitamin B12 and elevated methylmalonic acid and homocysteine.
Stein J et al. · European journal of neurology (2021)
Sehr groß Schaden
← SchlechterKein EffektBesser →
Borderline
B12 treatment (vs. the comparators) showed a non-significant association with symptom improvement (1.36 (0.66-2.79), n = 4, I2 = 28.9%).
Treatment with B1 was associated with a significant improvement in symptoms (5.34 [1.87-15.19], n = 3, I2 = 64.6%, p = 0.059).
Analysis of seven trials combined showed a non-significant higher odds ratio for improvement under treatment with the B-vitamins (2.58 [0.98-6.79], I2 = 80.0%, p < 0.001).
18Cancer risk and all-cause mortality with elevated vitamin B12Systematische ÜbersichtCited 9×2024
There was less consistent evidence linking vitamin B12 and mortality.
Amado-Garzon SB et al. · Cancer investigation (2024)
Sehr groß Schaden
← SchlechterKein EffektBesser →
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.
19Vitamin B12, EPA and DHA status during pregnancy and lactationMeta-AnalyseCited 2×2024
However, it is important to continue with research in this area that considers an adequate dietary anamnesis, integral evaluation of nutritional status, estimation of nutritional requirements and an individualized nutritional plan.
Sandoval Leiva T et al. · Nutricion hospitalaria (2024)
Eleven articles were selected in this review.
Well-planned vegetarian and vegan diets, with adequate supplementation of vitamin B12, EPA and DHA, are compatible during pregnancy and lactation, being a positive predictor of their content in breast milk.
A similar situation was observed in plasma levels in women supplemented with B12.
20Resolution of hallucinations with vitamin B12 treatmentSystematische ÜbersichtCited 7×2024
In the light of the high prevalence rate of vitamin B12 deficiency in the general population, the findings here presented should be interpreted with great caution.
Blom JD · Psychopathology (2024)
Sehr groß Nutzen
← SchlechterKein EffektBesser →
The hallucinations described therein are predominantly visual and/or auditory in nature, with 20% being specified as complex, compound, or panoramic.
Within an average of 2 months, full amelioration was thus obtained in 75% of the cases and partial amelioration in the remaining 25%.
Remarkably, a quarter of the cases involved therapy-resistant hallucinations that fully resolved under cobalamin monotherapy, while other neuropsychiatric manifestations of vitamin B12 deficiency disappeared in 60% of the treated cases.