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Bcx6.5
B-Complex – Forschung
Hilft vermutlich
52 begutachtete Studien
Was die Evidenz sagt
Hilft vermutlich
B-Complex half in etwa der Hälfte (5/8) der Studien, die einen Effekt gemessen haben — vielversprechend, aber nicht einhellig.
Die meiste Evidenz stammt aus hochwertigen Meta-Analysen und randomisierten Studien, veröffentlicht 2006–2026 mit einer typischen Studiengröße von 1,925 Teilnehmenden.
Basierend auf 52 Studien · 22 Meta-Analysen · 11 RCTs · 416,610 Teilnehmende insgesamt
Konfidenz
Hohe Konfidenz
Was die Studien gefunden haben
5geholfen3unklar· 44 weitere ohne bewertete Effektdaten
Nach Outcome
Neuroprotection & brain aging
Hilft vermutlich42 Studien
Cognitive functionB-Vitamine sind essenziell für den Homocystein-Stoffwechsel und die kognitive Gesundheit · 4-8 Wochen
Hilft vermutlich31 Studien
Heart & blood pressure
Überwiegend Mechanismus / Beobachtung13 Studien
Depression & moodBessere Stimmung und reduzierte Müdigkeit · 4-8 Wochen
Überwiegend Mechanismus / Beobachtung5 Studien
Therapeutic & clinical
Überwiegend Mechanismus / Beobachtung4 Studien
Women's healthUnterstützt einen gesunden Östrogenstoffwechsel und das hormonelle Gleichgewicht · 4-8 Wochen · Liefert essenzielle Nährstoffe für eine gesunde Schwangerschaft · Fortlaufend
Zu wenige bewertete Studien2 Studien
Anxiety & stressDer B-Vitamin-Status ist mit Stressresilienz und GABA-Synthese verbunden · 4-8 Wochen
Zu wenige bewertete Studien2 Studien
Safety profile
Zu wenige bewertete Studien1 Studie
In Zahlen
Aus 31 Studien mit messbaren Effekten gezogen
Wahrscheinlich echte Effekte
67%
über Studien hinweg
Untersuchte Personen
417k
typische Studie: 1925 Personen
Stärkste Designs
33
22 gepoolt, 11 randomisiert
Zeigte Nutzen
63%
5/8 Studien
Wie lange Studien liefen
3+ Monate
3
Untersuchte Populationen
Older adults3
General population2
Adults in areas without/with partial folic acid fortification1
Cancer patients1
Aktives Forschungsgebiet
27 Studien in den letzten 5 Jahren · Neueste Meta-Analyse: 2025
200620162026
1Global cognitive function improvementMeta-AnalyseCited 4×n=5,275 · very large study2025
The pooled findings indicated there is high-certainty evidence that vitamin B6, B9, or B12 supplementation has a very small benefit on global cognitive function in older adults.
Berg J et al. · Nutrition reviews (2025)
The pooled findings indicated there is high-certainty evidence that vitamin B6, B9, or B12 supplementation has a very small benefit on global cognitive function in older adults.
2Stroke 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).
3Cognitive function improvementMeta-AnalyseCited 8×n=42,768 · very large study2024
While mandatory FA fortification has the improved folic acid status, additional folate-based B vitamin supplements do not appear to influence cognitive function.
Zhang L et al. · Nutrients (2024)
Kaum spürbar Nutzen
← SchlechterKein EffektBesser →
Likely real
The meta-analysis on the effects of folate-based B vitamin supplementation on cognitive function showed a significant overall impact (Z = 3.84; p = 0.0001; SMD, 0.18; 95% CI, 0.09, 0.28).
Further analysis revealed that FA food fortification policies were not implemented in countries where folate-based B vitamin supplementation improved cognitive impairment in older adults (Z = 3.75; p = 0.0002; SMD, 0.27; 95% CI, 0.13, 0.40).
However, the FA intervention did not have significant outcomes in areas where FA food fortification policies were mandatory (Z = 0.75; p = 0.45; SMD, 0.03; 95% CI, -0.06, 0.13).
4Safety and efficacy in cancer treatmentsSystematische ÜbersichtCited 11×n=1,200 · large study2024
In this systematic review we concluded that B vitamin supplements have varying data regarding safety and efficacy in cancer.
Van de Roovaart HJ et al. · Journal of oncology pharmacy practice : official publication of the International Society of Oncology Pharmacy Practitioners (2024)
In this systematic review we concluded that B vitamin supplements have varying data regarding safety and efficacy in cancer.
Taking into account the etiology of the cancer, the specific B-vitamin, and the presence of any side effects could help guide utilization of the data found in this review.
Large, randomized controlled trials are needed to confirm these findings among various cancer diagnoses and stages.
5Cognitive 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.
6Stress reductionMeta-AnalyseCited 67×n=2,015 · very large study2019
B vitamin supplementation may particularly benefit populations who are at risk due to (1) poor nutrient status or (2) poor mood status.
Young LM et al. · Nutrients (2019)
Spürbar Nutzen
← SchlechterKein EffektBesser →
Likely real
Regarding individual facets of mood, B vitamin supplementation benefited stress (n = 958, SMD = 0.23, 95% CI = 0.02, 0.45, p = 0.03).
A benefit to depressive symptoms did not reach significance (n = 568, SMD = 0.15, 95% CI = -0.01, 0.32, p = 0.07), and there was no effect on anxiety (n = 562, SMD = 0.03, 95% CI = -0.13, 0.20, p = 0.71).
The review provides evidence for the benefit of B vitamin supplementation in healthy and at-risk populations for stress, but not for depressive symptoms or anxiety.
7Cognitive function improvementMeta-AnalyseCited 70×n=1,925 · large study2019
Raised total plasma homocysteine is associated with an increased risk of cognitive impairment and dementia, although available evidence from randomized controlled trials shows no obvious cognitive benefit of lowering homocysteine using B vitamins.
Ford AH et al. · Drugs & aging (2019)
Kein klarer Effekt
← SchlechterKein EffektBesser →
B-vitamin supplementation did not show an improvement in Mini-Mental State Examination scores for individuals with (mean difference 0.16, 95% confidence interval - 0.18 to 0.51) and without (mean difference 0.04, 95% confidence interval - 0.10 to 0.18) cognitive impairment compared to placebo.
Raised total plasma homocysteine is associated with an increased risk of cognitive impairment and dementia, although available evidence from randomized controlled trials shows no obvious cognitive benefit of lowering homocysteine using B vitamins.
Existing trials vary greatly in the type of supplementation, population sampled, study quality, and duration of treatment, thereby making it difficult to draw firm conclusions from existing data.
8Major adverse cardiovascular events (MACE)Meta-AnalyseCited 31×n=57,952 · very large study2014
B vitamin supplementation, when used for primary or secondary prevention, is not associated with a reduction in MACE, total mortality, cardiac death, MI, or stroke.
Zhang C et al. · PloS one (2014)
B vitamin supplementation, when used for primary or secondary prevention, is not associated with a reduction in MACE, total mortality, cardiac death, MI, or stroke.
9Meta-AnalyseCited 66×n=3,089 · very large study2013
Daily supplementation with folic acid, vitamin B6, and vitamin B12 to a self-selected clinical trial cohort of cognitively unimpaired patients with previous stroke or transient ischemic attack lowered mean tHcy but had no effect on the incidence of cognitive impairment or cognitive decline, as measured by the MMSE, during a median of 2.8 years.
Hankey GJ et al. · Stroke (2013)
A total of 3089 participants (38%) voluntarily undertook the MMSE>6 months after the qualifying stroke; 2608 participants were cognitively unimpaired (MMSE≥24), of whom 2214 participants (1110 B-vitamins versus 1104 placebo) had follow-up MMSEs during 2.8 years (median).
10Meta-AnalyseCited 14×n=57,143 · very large study2013
Our study indicates that B-vitamin supplementation is not associated with a lower risk of stroke based on relative and absolute measures of association.
Zhang C et al. · PloS one (2013)
Our study indicates that B-vitamin supplementation is not associated with a lower risk of stroke based on relative and absolute measures of association.
Subgroup analyses suggested that B-vitamin supplementation can effectively reduce the risk of stroke if included trials had a man/woman ratio of more than 2 or subjects received dose of folic acid less than 1 mg.
11Meta-AnalyseCited 79×n=54,913 · very large study2013
B vitamin supplementation for homocysteine reduction significantly reduced stroke events, especially in subjects with certain characteristics who received appropriate intervention measures.
Ji Y et al. · Neurology (2013)
B vitamin supplementation for homocysteine reduction significantly reduced stroke events, especially in subjects with certain characteristics who received appropriate intervention measures.
12Meta-AnalyseCited 89×n=47,921 · very large study2012
B vitamin supplementation has a significant protective effect on stroke, but none on the risk of CVD, MI, CHD, cardiovascular death, or all-cause mortality.
Huang T et al. · Clinical nutrition (Edinburgh, Scotland) (2012)
B vitamin supplementation has a significant protective effect on stroke, but none on the risk of CVD, MI, CHD, cardiovascular death, or all-cause mortality.
These models provide possible explanations for why micronutrient supplementation could ameliorate some mental symptoms.
Kaplan BJ et al. · Psychological Bulletin (2007)
Since the 1920s, there have been many studies on individual vitamins (especially B vitamins and Vitamins C, D, and E), minerals, and vitamin-like compounds in relation to mood.
Recent investigations with multi-ingredient formulas are especially promising.
Four explanatory models are presented, suggesting that mood symptoms may be expressions of inborn errors of metabolism, manifestations of deficient methylation reactions, alterations of gene expression by nutrient deficiency, and/or long-latency deficiency diseases.
The findings of this systematic review suggest that supplementation of B Complex vitamins, especially folic acid, may have a positive effect on delaying and preventing the risk of cognitive decline.
Gil Martínez V et al. · Nutrients (2022)
The findings of this systematic review suggest that supplementation of B Complex vitamins, especially folic acid, may have a positive effect on delaying and preventing the risk of cognitive decline.
Ascorbic acid and a high dose of vitamin E, when given separately, also showed positive effects on cognitive performance, but there is not sufficient evidence to support their use.
The results of vitamin D supplementation trials are not conclusive in assessing the potential benefits that vitamin D might have on cognition.
However, it did not translate into cognitive improvement, indicating that the existing data on vitamin B-induced improvement in cognition by lowering homocysteine levels are conflicting.
Zhang DM et al. · Journal of geriatric psychiatry and neurology (2017)
The results reveal that the intervention group achieved significantly greater reduction in homocysteine levels than the control (pooled difference in means = -3.625, 95% confidence interval [CI] = -5.642 to -1.608, P < .001).
However, no significant difference in MMSE (pooled difference in means = 0.027, 95% CI = -0.518 to 0.573, P = 0.921) was observed between the groups.
Taken together, vitamin B supplementation was effective in reducing serum homocysteine levels.
B vitamin supplementation might not be effective in preventing fracture and improving bone turnover.
Ruan J et al. · Medical science monitor : international medical journal of experimental and clinical research (2015)
B vitamin supplementation might not be effective in preventing fracture and improving bone turnover.
However, the possible benefits in selective populations, such as populations with very high plasma Hcy and from regions without B vitamin fortification should be explored in the future.
Similarly, folic acid alone or vitamins B in combination are unable to stabilize or slow decline in cognition, function, behavior, and global change of AD patients.
Li MM et al. · Current Alzheimer research (2014)
Collectively, weak evidence of benefits was observed for the domains of memory in patients with MCI.
Nevertheless, future standard RCTs are still needed to determine whether it was still significant in larger populations.
However, the data does not yet provide adequate evidence of an effect of vitamins B on general cognitive function, executive function and attention in people with MCI.
It remains to be established if prolonged treatment with B-vitamins can reduce the risk of dementia in later life.
Ford AH et al. · Journal of Alzheimer's disease : JAD (2012)
B-vitamin supplementation did not show an improvement in cognitive function for individuals with (SMD = 0.10, 95%CI -0.08 to 0.28) or without (SMD = -0.03, 95%CI -0.1 to 0.04) significant cognitive impairment.
Supplementation of vitamins B12, B6, and folic acid alone or in combination does not appear to improve cognitive function in individuals with or without existing cognitive impairment.
It remains to be established if prolonged treatment with B-vitamins can reduce the risk of dementia in later life.