40 peer-reviewed studies · Evidence score: 9/10
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.
Zhang N et al. • The American journal of clinical nutrition (2024)
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 L et al. • Nutrients (2024)
While mandatory FA fortification has the improved folic acid status, additional folate-based B vitamin supplements do not appear to influence cognitive function.
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.
Wang Z et al. • Nutrition reviews (2022)
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.
Young LM et al. • Nutrients (2019)
B vitamin supplementation may particularly benefit populations who are at risk due to (1) poor nutrient status or (2) poor mood status.
Ford AH et al. • Drugs & aging (2019)
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.
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.
Hankey GJ et al. • Stroke (2013)
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.
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.
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.
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.
Young LM et al. • Human Psychopharmacology (2019)
B vitamin supplementation may benefit mood, particularly stress and anxiety.
Liew SC, Gupta ED • Journal of Nutritional Biochemistry (2015)
Methylated forms of B vitamins may be more effective for individuals with MTHFR polymorphisms.
Amanat S et al. • Advances in nutrition (Bethesda, Md.) (2025)
The substantial heterogeneity among studies hinders conclusions about other dietary strategies.
Kennedy DO • Nutrients (2016)
B vitamins are essential for all aspects of brain function, and supplementation benefits those with suboptimal status.
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.
Solfrizzi V et al. • Neuroscience and biobehavioral reviews (2018)
Antioxidant-rich foods (nuts, grapes, cherries) and fatty acid supplementation, mainly n-3 polyunsaturated fatty acids (PUFA), improved specific cognitive domains and cognitive-related outcomes in ...
de Macedo TSG et al. • Systematic reviews (2025)
There is a clear need for more robust studies across all Brazilian regions to improve understanding of vitamin deficiency rates and to support effective nutritional interventions.
Zhang DM et al. • Journal of geriatric psychiatry and neurology (2017)
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.