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B127.5
Vitamin B12 – Forschung
Hilft wahrscheinlich
335 begutachtete Studien
Was die Evidenz sagt
Hilft vermutlich
Vitamin B12 half in etwa der Hälfte (16/23) der Studien, die einen Effekt gemessen haben — vielversprechend, aber nicht einhellig.
Die meiste Evidenz stammt aus hochwertigen Meta-Analysen und randomisierten Studien, veröffentlicht 1966–2026 mit einer typischen Studiengröße von 859 Teilnehmenden.
Basierend auf 331 Studien · 42 Meta-Analysen · 229 RCTs · 507,431 Teilnehmende insgesamt
Konfidenz
Hohe Konfidenz
Was die Studien gefunden haben
16geholfen3unklar4nicht geholfen· 308 weitere ohne bewertete Effektdaten
Nach Outcome
B12 deficiency & anemia
Hilft wahrscheinlich222 Studien
Heart & blood pressure
Hilft wahrscheinlich74 Studien
Therapeutic & clinical
Hilft vermutlich57 Studien
Cognitive functionMethylierungsunterstützung, essenziell für die Neurotransmittersynthese und das Gedächtnis · 4-8 Wochen
Hilft wahrscheinlich33 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 vermutlich21 Studien
Safety profile
Hilft wahrscheinlich12 Studien
Glucose & metabolic
Hilft vermutlich10 Studien
Neuroprotection & brain agingUnterstützt die Erhaltung des Myelins; ein Mangel führt zu neurologischen Schäden · Fortlaufend
Überwiegend Mechanismus / Beobachtung8 Studien
Depression & moodDie Korrektur eines Mangels verbessert Depressionen und kognitiven Nebel · 4-8 Wochen
Überwiegend Mechanismus / Beobachtung7 Studien
Bone healthUnterstützt die Knochenmineraldichte und die Festigkeit des Skeletts · 8-12 Wochen
Überwiegend Mechanismus / Beobachtung7 Studien
Energy & fatigueWiederhergestellte Energie bei Mangel; moderater Nutzen bei ausreichender Versorgung · 2-4 Wochen
Überwiegend Mechanismus / Beobachtung3 Studien
ALS & motor-neuron disease
Zu wenige bewertete Studien2 Studien
Immune support
Zu wenige bewertete Studien2 Studien
Anxiety & stress
Zu wenige bewertete Studien1 Studie
In Zahlen
Aus 62 Studien mit messbaren Effekten gezogen
Wahrscheinlich echte Effekte
89%
über Studien hinweg
Untersuchte Personen
507k
typische Studie: 859 Personen
Stärkste Designs
271
42 gepoolt, 229 randomisiert
Zeigte Nutzen
70%
16/23 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
Patients with vitiligo1
Aktives Forschungsgebiet
107 Studien in den letzten 5 Jahren · Neueste Meta-Analyse: 2026
196619962026
1major adverse cardiovascular eventsMeta-Analysen=68,363 · very large study2026
Einfach gesagt: 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).
Einfach gesagt: 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.
3Serum vitamin and mineral levelsMeta-Analysen=8,542 · very large study2024
Einfach gesagt: 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)
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.
4Stroke risk reductionMeta-Analysen=76,664 · very large study2024
Einfach gesagt: 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).
5Vitamin B12 level increaseMeta-Analysen=4,275 · very large study2024
Einfach gesagt: 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-Analysen=2,852 · very large study2023
Einfach gesagt: 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-Analysen=28,597 · very large study2023
Einfach gesagt: 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.
13Cognitive function improvementMeta-Analysen=6,276 · very large study2021
Einfach gesagt: 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.
14Folate levelsMeta-Analysen=770 · large study2024
Einfach gesagt: 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.
17Glycemic control in T2DM with peripheral neuropathyMeta-Analyse2025
Einfach gesagt: 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.