Vitamin B12 ： Age-Related Cognitive Decline

Combined B12 and folate supplementation slowed brain atrophy rate in MCI patients compared to placebo. Homocysteine reduction appears to be the primary mechanism linking B12 status to cognitive preservation.

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結論

Key Study Findings

Review

Vitamin B12 deficiency among older adults and its associations with geriatric syndromes.

Dose: None vs: None Outcome: None 効果: None None

対象集団: older adults with vitamin B12 deficiency and geriatric syndromes

Meta-Analysis

Associations between Diet and Cognitive Function in Stroke Survivors: A Systematic Review and Meta-analysis.

Dose: None vs: Standard care or placebo Outcome: Global cognition in stroke survivors 効果: SMD=0.62 (energy-protein); SMD=-0.40 (B-vitamins) 0.009 (protein); 0.02 (B-vit)

対象集団: Adult stroke survivors (20 trials + 14 observational)

Controlled Clinical Trial 32 weeks

Vitamin B12 supplementation attenuates endoplasmic reticulum stress and neuronal cell death in the cerebral cortex …

Dose: 50 ug/kg diet vs 25 ug/kg diet vs: HFHS diet without extra B12 Outcome: ER stress and neuronal cell death in cerebral … 効果: None None

対象集団: Male C57BL/6J mice on high-fat high-sucrose diet

Other

Estimating effects of serum vitamin B12 levels on psychiatric disorders and cognitive impairment: a Mendelian …

Dose: None vs: None Outcome: Effect of serum B12 on psychiatric disorders (MR) 効果: OR 1.02 [1.00-1.04] for depression per SD increase 0.11 (depression); 0.39 (educa

対象集団: General population (Mendelian randomization, large GWAS)

Systematic Review

Impact of Vegan and Vegetarian Diets on Neurological Health: A Critical Review.

Dose: None vs: None Outcome: Neurological health outcomes 効果: None None

対象集団: None

Review

Unlocking the cellular mystery: how proton pump inhibitors may alter the dementia landscape.

Dose: None vs: None Outcome: Dementia risk with PPI use 効果: None None

対象集団: PPI users and dementia risk (review)

Key Statistics

研究数

2800

参加者数

↑

Positive

グレード

Referenced Papers

Vitamin B12 deficiency among older adults and its associations with geriatric syndromes. Review

Current opinion in … 2026

Impact of Vegan and Vegetarian Diets on Neurological Health: A Critical Review. Systematic Review

Nutrients 2025 22 件の引用

Unlocking the cellular mystery: how proton pump inhibitors may alter the dementia landscape. Review

Brain research 2025 6 件の引用

The Neurological Sequelae of Vitamin B12 Deficiency: A Systematic Review and Randomized Controlled Trial. Review

Cureus 2025 4 件の引用

Estimating effects of serum vitamin B12 levels on psychiatric disorders and cognitive impairment: a Mendelian randomization study. Other

Communications medicine 2025 3 件の引用

Associations between Diet and Cognitive Function in Stroke Survivors: A Systematic Review and Meta-analysis. Meta-Analysis

Advances in nutrition … 2025 1 件の引用

Vitamin B12 supplementation attenuates endoplasmic reticulum stress and neuronal cell death in the cerebral cortex of high-fat high-sucrose-fed male mice. Other

Nutrition (Burbank, Los … 2025

Diagnosis, Treatment and Long-Term Management of Vitamin B12 Deficiency in Adults: A Delphi Expert Consensus. Other

Journal of clinical … 2024 29 件の引用

Proton Pump Inhibitors and Cognitive Health: Review on Unraveling the Dementia Connection and Co-morbid Risks. Review

Current Alzheimer research 2024 14 件の引用

Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency. Other

Science translational medicine 2024 12 件の引用

Vitamin B12 and Age-Related Cognitive Decline-Dementia and "Alzheimer's Disease". Other

Food and nutrition … 2024 2 件の引用

Homocysteine levels, genetic background, and cognitive impairment in Parkinson's disease. Meta-Analysis

Journal of neurology 2023 34 件の引用

Sustaining an ageing population: the role of micronutrients in frailty and cognitive impairment. Review

The Proceedings of … 2023 27 件の引用

Markers of Vitamin B12 Status in Relation to Cerebrospinal Fluid Biomarkers of Alzheimer's Disease and Cognitive Performance. Other

Annals of neurology 2023 15 件の引用

Vitamin B12 supplementation improves cognitive function in middle aged and elderly patients with cognitive impairment. RCT

Nutricion hospitalaria 2023 13 件の引用

Homocysteine and nutritional biomarkers in cognitive impairment. Other

Molecular and cellular … 2023 8 件の引用

Dietary folate intake and its association with longitudinal changes in cognition function. Other

Clinical nutrition ESPEN 2023 5 件の引用

Vitamin Supplementation and Dementia: A Systematic Review. Systematic Review

Nutrients 2022 76 件の引用

Neuropsychiatric manifestations in vitamin B12 deficiency. Other

Vitamins and hormones 2022 28 件の引用

Diet, Gut Microbiome, and Cognitive Decline. Review

Current nutrition reports 2022 25 件の引用

Effect of a Vegan Diet on Alzheimer's Disease. Review

International journal of … 2022 23 件の引用

Cognition, oxidative stress and vitamin B12 levels evaluation on patients under long-term omeprazole use. Other

The Journal of … 2022 13 件の引用

Cognitive function and vitamin B12 and D among community-dwelling elders: A cross-sectional study. Other

Clinical nutrition ESPEN 2022 12 件の引用

Nitrous Oxide/Whippits-Induced Thoracic Spinal Cord Myelopathy and Cognitive Decline With Normal Serum Vitamin B₁₂. Case Report

Cureus 2022 6 件の引用

Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia. Other

Cureus 2020 65 件の引用

Vitamin B12, B6, or Folate and Cognitive Function in Community-Dwelling Older Adults: A Systematic Review and Meta-Analysis. Meta-Analysis

Journal of Alzheimer's … 2020 34 件の引用

Association between Vitamin B12 levels and cognitive function in the elderly Korean population. Observational

Medicine 2020 29 件の引用

Vitamin B-Can it prevent cognitive decline? A systematic review and meta-analysis. Meta-Analysis

Systematic reviews 2020 29 件の引用

Can Nutritional Adequacy Help Evade Neurodegeneration in Older Age? A Review. Review

Cureus 2020 5 件の引用

Mediterranean diet: The role of long-chain ω-3 fatty acids in fish; polyphenols in fruits, vegetables, cereals, coffee, tea, cacao and … Review

Revue neurologique 2019 361 件の引用

Homocysteine and Dementia: An International Consensus Statement. Other

Journal of Alzheimer's … 2018 281 件の引用

Over-the-Counter Supplement Interventions to Prevent Cognitive Decline, Mild Cognitive Impairment, and Clinical Alzheimer-Type Dementia: A Systematic Review. Systematic Review

Annals of internal … 2018 119 件の引用

Vitamin K Antagonists and Cognitive Decline in Older Adults: A 24-Month Follow-Up. Observational

Nutrients 2018 30 件の引用

Vitamin Status and the Development of Postoperative Cognitive Decline in Elderly Surgical Oncologic Patients. Other

Annals of surgical … 2018 22 件の引用

Vitamin B12 Deficiency: Recognition and Management. Other

American family physician 2017 282 件の引用

Homocysteine, B Vitamins, and Cognitive Impairment. Review

Annual review of … 2016 432 件の引用

Metabolic vitamin B12 deficiency: a missed opportunity to prevent dementia and stroke. Review

Nutrition research (New … 2016 131 件の引用

Is Metformin-Induced Vitamin B12 Deficiency Responsible for Cognitive Decline in Type 2 Diabetes? Other

Indian journal of … 2016 23 件の引用

Novel insights into the effect of vitamin B₁₂ and omega-3 fatty acids on brain function. Review

Journal of biomedical … 2016

Individually modifiable risk factors to ameliorate cognitive aging: a systematic review and meta-analysis. Meta-Analysis

Climacteric : the … 2015 92 件の引用

Vitamin B12 and cognitive decline. Other

Annals of Indian … 2015 1 件の引用

B vitamin polymorphisms and behavior: evidence of associations with neurodevelopment, depression, schizophrenia, bipolar disorder and cognitive decline. Review

Neuroscience and biobehavioral … 2014 148 件の引用

Consideration of nutrient levels in studies of cognitive decline. Review

Nutrition reviews 2014 25 件の引用

Micronutrients supplementation and nutritional status in cognitively impaired elderly persons: a two-month open label pilot study. Other

Nutrition journal 2013 26 件の引用

Vitamin B12 and cognitive function: an evidence-based analysis. Review

Ontario health technology … 2013

Vitamin B₁₂ status, cognitive decline and dementia: a systematic review of prospective cohort studies. Systematic Review

The British journal … 2012 87 件の引用

Late-adult onset Leigh syndrome. Case Report

Journal of clinical … 2012 54 件の引用

Supplementing cognitive aging: a selective review of the effects of ginkgo biloba and a number of everyday nutritional substances. Review

Experimental aging research 2010 21 件の引用

Normal cognitive decline or dementia? Other

The Practitioner 2010

Homocysteine, vitamin B12, folate and cognitive functions: a systematic and critical review of the literature. Systematic Review

International journal of … 2009 125 件の引用

Biochemical indicators of vitamin B12 and folate insufficiency and cognitive decline. Other

Neurology 2009 124 件の引用

Prospective study of plasma folate, vitamin B12, and cognitive function and decline. Other

Epidemiology (Cambridge, Mass.) 2006 49 件の引用

Homocysteine and cognition--a historical perspective. Review

Journal of Alzheimer's … 2006 37 件の引用

Dietary folate and vitamin B12 intake and cognitive decline among community-dwelling older persons. Other

Archives of neurology 2005 263 件の引用

Vitamin B12 and folate depletion in cognition: a review. Review

Neurology India 2004 71 件の引用

Folic acid with or without vitamin B12 for cognition and dementia. Systematic Review

The Cochrane database … 2003 263 件の引用

Nutrients, age and cognitive function. Review

Current opinion in … 1998 30 件の引用

Dosage & Usage

mg = milligrams · mcg = micrograms (1,000× smaller) · IU = International Units

一般的な使用量

general:: 2.4 mcg/day (RDA)
deficiency:: 1,000-2,000 mcg/day
cognitivesupport:: 500-1,000 mcg/day

上限量： No established UL (water-soluble, low toxicity)

研究で検討された用量

用量	期間	効果	N
None	--	Positive	--
None	--	Mixed	--
50 ug/kg diet vs 25 ug/kg diet	32 weeks	Positive	--
None	--	Neutral	--
None	--	Mixed	--
None	--	Negative	--
None	--	Mixed	--
None	--	Positive	--

推奨摂取タイミング： Morning, on empty stomach for better absorption (sublingual)

Safety & Side Effects

報告されている副作用

⚠ Generally very well-tolerated
⚠ Rare: acne-like eruptions at high doses
⚠ Injection site reactions (injectable form)

既知の相互作用

● Metformin (reduces B12 absorption)
● Proton pump inhibitors (reduce B12 absorption)
● Colchicine (reduces B12 absorption)

耐容上限摂取量： No established UL (water-soluble, low toxicity)

サプリメントの摂取を開始する前に、必ず医療専門家にご相談ください。

Frequently Asked Questions

Does Vitamin B12 help with Age-Related Cognitive Decline?

Based on 12 studies with 2,800 participants, there is moderate evidence from clinical studies that Vitamin B12 may support Age-Related Cognitive Decline management. Our evidence grade is B (Good Evidence).

How much Vitamin B12 should I take for Age-Related Cognitive Decline?

Studies have used various dosages. A commonly studied range is 2.4 mcg/day (RDA). Always consult your healthcare provider before starting any supplement regimen.

Are there side effects of Vitamin B12?

Reported side effects may include Generally very well-tolerated, Rare: acne-like eruptions at high doses, Injection site reactions (injectable form). Most side effects are mild and dose-dependent. Consult your doctor if you experience any adverse reactions.

How strong is the evidence for Vitamin B12 and Age-Related Cognitive Decline?

We rate the evidence as Grade B (Good Evidence). This rating is based on 12 peer-reviewed studies with 2,800 total participants. The overall direction of effect is positive.

Related Evidence

に関する他の成分： Age-Related Cognitive Decline

Omega-3 Fatty Acids (DHA/EPA) A Phosphatidylserine B Bacopa monnieri B Curcumin B Ginkgo biloba C Panax Ginseng C

Vitamin B12 他の症状・状態について

Nutritional Deficiency Cognitive Impairment A

総合評価

Evidence Strength72%

High confidence

研究の内訳

RCT (1)Meta (5)Other (6)

代替成分との比較

この症状に対する他の成分との比較をご覧ください。

に関するすべての成分を見る： Age-Related Cognitive Decline

詳しく見る

FDAに関する免責事項: これらの記述は米国食品医薬品局（FDA）による評価を受けていません。本ウェブサイトの製品および情報は、疾病の診断、治療、治癒、または予防を目的としたものではありません。表示されているエビデンスグレードは、公開された査読済み研究の分析に基づいており、医療上の助言を構成するものではありません。サプリメントの摂取を開始する前に、必ず医療専門家にご相談ください。