Folic Acid, Folate And Dementia

Folic Acid, Folate And Dementia

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Katie Stone - Naturopath

Written By:

Katie Stone - Naturopath
Kari Asadorian - BSN, RN

Medical Reviewer:

Kari Asadorian - BSN, RN
Dr. Nare Simonyan - PhD Pharmaceutical Science

Edited By:

Dr. Nare Simonyan - PhD Pharmaceutical Science
Last updated:

What is Dementia?

Dementia is the progressive decline in several areas of cognitive function, including memory, thinking, language, learning, concentration, and mood. This decline eventually impairs the ability to perform everyday activities.1

Dementia is an umbrella term for neurocognitive decline, and is now referred to as ‘major neurocognitive disorder’ (MND). The term dementia is often used synonymously with Alzheimer's disease, although this is only one cause of cognitive decline.


Dementia can be divided into two main categories: primary (degenerative) and secondary causes. The most prevalent degenerative dementias include Alzheimer's dementia, frontotemporal dementia, dementia associated with Parkinson’s disease, and dementia with Lewy bodies. Other causes of dementia include vascular disease, central nervous system infections, trauma, metabolic impairments, and several potentially reversible conditions.2


Alzheimer’s disease often leads to significant atrophy of the brain (mainly the temporal, frontal, and parietal regions) along with beta‑amyloid plaques and neurofibrillary tangles.3 Beta-amyloid causes significant damage to brain cells, including intracellular calcium accumulation, oxygen radical formation, nitric oxide synthesis, and inflammation.4


Alzheimer’s disease accounts for around two‑thirds of dementia cases in older adults, and the overall prevalence rises significantly with age.5

What Causes Dementia?

The main risk factor in dementia is age, but both genetic and environmental risk factors can play a role. Nutritional deficiencies, thyroid disorders, infections, toxins, autoimmune disorders, metabolic and cardiovascular issues, and psychiatric conditions have also been linked to the development of dementia.6 Many of these may be preventable or at least partially reversible.


Research has suggested that the most common reversible causes of dementia include alcoholism, vitamin B12 deficiency, and hypothyroidism.7 The American Academy of Neurology recommends that routine evaluations for dementia include screening for hypothyroidism, vitamin B12 deficiency, and structural abnormalities.8


  • Plaques
    Alzheimer’s disease is characterized by the accumulation of beta-amyloid and tau in the brain, which plays a major role in cognitive decline and other brain changes alongside environmental and lifestyle factors. The rate of neurodegeneration can increase with vascular changes, chronic inflammation, and metabolic disorders such as type 2 diabetes and metabolic syndrome.9

  • Cardiovascular
    Vascular dementia is associated with stroke, ischemia, and structural damage to blood vessels in the brain. These effects may result from vascular risk factors and cardiac disease.

  • Nutritional deficiencies
    Research has suggested that concurrent deficiencies in omega-3 fatty acids, B vitamins, and vitamin D are associated with higher rates of cognitive decline and an increased risk of dementia.10 Suboptimal levels of all three nutrients were associated with a four‐fold increased risk of dementia compared to individuals without suboptimal statuses.
    Lower folate levels and higher homocysteine levels are significantly associated with higher risks of dementia.11
    A 2022 study found that serum folate deficiency (<4.4 ng/mL) was linked to significantly higher incident dementia and all‑cause mortality. Patients with folate deficiency were 68% more likely to be diagnosed with dementia and nearly three times more likely to die from any cause.12
    Vitamin B12 deficiency is linked to impaired cognition and memory in part due to its role in myelination and one‑carbon metabolism. Elevated homocysteine levels are also often associated with Alzheimer’s disease and stroke.13

  • Alcohol consumption
    Several studies show that higher alcohol intake is associated with an increased risk. Heavy drinking significantly elevates dementia risk and is associated with distinct alcohol‑related dementias.14
    Chronic exposure to alcohol triggers oxidative stress and neuroinflammation, leading to reduced grey matter, impaired protein clearance, and vascular injury.15

  • High homocysteine
    Elevated plasma total homocysteine is a significant risk factor for cognitive decline, dementia, and Alzheimer’s disease in older adults. A 2024 longitudinal study concluded that homocysteine levels are linked to the progression from mild cognitive impairment (MCI) to dementia due to its role in neurodegeneration.16
    Homocysteine is described as neurotoxic as it promotes oxidative stress, endothelial dysfunction, excitotoxicity, and small‑vessel damage, all of which can lead to vascular and neurodegenerative dementias.17

Supplements That Help With Dementia

B9 and B12 are essential for one-carbon methylation and the conversion of homocysteine and generation of S‑adenosylmethionine (SAMe), the universal methyl donor required for DNA synthesis. B12 is a vital component of myelin, the protective sheath surrounding neurons.18
A 2022 meta-analysis found that B vitamin supplementation of folate, B6, and B12 was associated with a small but statistically significant slowing of cognitive decline, especially when supplementation began early and/or continued over long periods. The study also indicates that higher intake of dietary folate was associated with a reduced risk of incident dementia in non-dementia aged populations.19


A 2019 study found that a small group of Alzheimer’s patients supplemented with a combination of folic acid and vitamin B12 showed improvements in cognitive function, including naming, orientation, and attention. Homocysteine and inflammatory markers were also significantly reduced, while SAMe and SAMe/SAH ratios increased. The authors concluded that folic acid and B12 supplements could be beneficial for slowing the progression of Alzheimer’s.20


A 2025 study reported that higher riboflavin (B2) intake may be associated with lower dementia risk. High dietary intake of folate and B6 also appeared to reduce the risk of dementia by about 20%.21


A 2020 study found that 84% of Alzheimer’s patients reported marked symptomatic improvement after vitamin B12 replacement therapy, while Mini-Mental State Examination (MMSE) scores improved in 78% of patients.22

Folic Acid, Folate And Dementia

Key Takeaways

  • Icon Dementia is multifactorial, but the main causes include age, nutritional deficiencies, genetics, and environmental contributors.
  • Icon B vitamins play a central role in neurocognitive health, and deficiency in B9 (folate) and B12 in particular has been linked to dementia.
  • Icon Studies suggest that supplementation with folate and B12 may help slow cognitive decline.

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Frequently Asked Questions about Folic Acid and Dementia

Does folic acid help dementia?

Some research has shown that folic acid combined with B12 can improve cognitive function in patients with Alzheimer’s. Higher intake of dietary folate is also associated with reduced risk of dementia. This may be because folate is required for managing homocysteine levels, and high homocysteine is associated with greater risk of developing dementia.23

Can folate deficiency cause dementia?

Folate deficiency is associated with higher risk of dementia, although it may not be a sole cause. It has also been shown that sufficient intake of folate (from food or supplements) can help protect against Alzheimer’s disease.24

Does lack of vitamin B6 and B12 cause dementia?

Research has shown that B6 and B12 deficiency are clearly associated with cognitive impairment and dementia, and may increase the risk of dementia in older adults. Severe vitamin B12 deficiency in particular can lead to memory loss, confusion, and behavior changes, but these symptoms may improve when the B12 deficiency is treated.25

What are the side effects of folic acid in the elderly?

Folic acid is generally well-tolerated in the elderly when taken in the recommended dosage. Very high dosages may cause mild gastrointestinal symptoms in some people. There is also a risk of masking B12 deficiency if folic acid is taken without assessing B12 levels first, which can cause serious harm to cognitive function and nervous system function.

References

  1. Rehab Hafiz, Lama Alajlani, Albatool Ali, Ghadah A Algarni, Hassan Aljurfi, Omar Abdullah M Alammar, Maria Y Ashqan, Alanoud Alkhashan; "The Latest Advances in the Diagnosis and Treatment of Dementia"; Cureus; 2023 Dec

    https://pmc.ncbi.nlm.nih.gov/articles/PMC10787596/

  2. Mayank Mundada, Pradnya M Diggikar, Ankit Shokeen, Raju Hansini Reddy, Arun B Oommen, Tushar Pancholi, Bhavya Yammanuru, Sree vidya Yekkaluru, Janani R, Akhilesh Jagirdar; "Comprehensive Analysis of Dementia Types and Risk Factors: A Study From a Tertiary Care Center in India"; Cureus; 2024 Jun

    https://pmc.ncbi.nlm.nih.gov/articles/PMC11260209/

  3. Rehab Hafiz, Lama Alajlani, Albatool Ali, Ghadah A Algarni, Hassan Aljurfi, Omar Abdullah M Alammar, Maria Y Ashqan, Alanoud Alkhashan; "The Latest Advances in the Diagnosis and Treatment of Dementia"; Cureus; 2023 Dec

    https://pmc.ncbi.nlm.nih.gov/articles/PMC10787596/

  4. Ali Azargoonjahromi; "The duality of amyloid-β: its role in normal and Alzheimer’s disease states"; Mol Brain.; 2024 Jul

    https://pmc.ncbi.nlm.nih.gov/articles/PMC11256416/

  5. Forshing Lui, Jack W. Tsao; "Alzheimer Disease"; StatPearls [Internet]; 2020 Feb

    https://www.ncbi.nlm.nih.gov/books/NBK499922/

  6. Mayank Mundada, Pradnya M Diggikar, Ankit Shokeen, Raju Hansini Reddy, Arun B Oommen, Tushar Pancholi, Bhavya Yammanuru, Sree vidya Yekkaluru, Janani R, Akhilesh Jagirdar; "Comprehensive Analysis of Dementia Types and Risk Factors: A Study From a Tertiary Care Center in India"; Cureus; 2024 Jun

    https://pmc.ncbi.nlm.nih.gov/articles/PMC11260209/

  7. Mayank Mundada, Pradnya M Diggikar, Ankit Shokeen, Raju Hansini Reddy, Arun B Oommen, Tushar Pancholi, Bhavya Yammanuru, Sree vidya Yekkaluru, Janani R, Akhilesh Jagirdar; "Comprehensive Analysis of Dementia Types and Risk Factors: A Study From a Tertiary Care Center in India"; Cureus; 2024 Jun

    https://pmc.ncbi.nlm.nih.gov/articles/PMC11260209/

  8. Elizabeth A. Bevins, Jonathan Peters, Gabriel C. Léger; "The Diagnosis and Management of Reversible Dementia Syndromes"; Current Treatment Options in Neurology; 2021 Jan

    https://link.springer.com/article/10.1007/s11940-020-00657-x

  9. Jae Woong Sull, Donald A McClain; "Metabolic Disorders and Complications"; Diabetes Metab Syndr Obes.; 2025 Dec

    https://pmc.ncbi.nlm.nih.gov/articles/PMC12730181/

  10. Jeanne Neuffer, Marjorie Gourru, Aline Thomas, Sophie Lefèvre-Arbogast, Alexandra Foubert-Samier, Catherine Helmer, Cécile Delcourt, Catherine Féart, Cécilia Samieri; "A Biological Index to Screen Multi-Micronutrient Deficiencies Associated with the Risk to Develop Dementia in Older Persons from the Community"; J Alzheimers Dis.; 2022

    https://pubmed.ncbi.nlm.nih.gov/34806604/

  11. Zhibin Wang, Wei Zhu, Yi Xing, Jianping Jia, Yi Tang; "B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis"; Nutr Rev.; 2022 Mar

    https://pubmed.ncbi.nlm.nih.gov/34432056/

  12. Anat Rotstein, Arad Kodesh, Yair Goldberg, Abraham Reichenberg, Stephen Z Levine; "Serum folate deficiency and the risks of dementia and all-cause mortality: a national study of old age"; BMJ Mental Health; 2022 Mar

    https://mentalhealth.bmj.com/content/25/2/63

  13. Shazia Jatoi, Abdul Hafeez, Syeda Urooj Riaz, Aijaz Ali, Muhammad Ishaq Ghauri, Maham Zehra; "Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia"; Cureus; 2020 Feb

    https://pmc.ncbi.nlm.nih.gov/articles/PMC7077099/

  14. Anya Topiwala, Daniel F Levey, Hang Zhou, Joseph D Deak, Keyrun Adhikari, Klaus P Ebmeier, Steven Bell, Stephen Burgess, Thomas E Nichols, Michael Gaziano, Murray Stein, Joel Gelernter; "Alcohol use and risk of dementia in diverse populations: evidence from cohort, case-control and Mendelian randomisation approaches"; BMJ Evid Based Med.; 2026 Jan

    https://pubmed.ncbi.nlm.nih.gov/40987604/

  15. Nishtha Singh, Shouvik Kumar Nandy, Aditi Sharma, Vansh, Arif Jamal Siddiqui, Lalit Sharma; "Chronic Alcohol Use and Accelerated Brain Aging: Shared Mechanisms with Alzheimer’s Disease Pathophysiology"; Brain Sci.; 2025 Dec

    https://pmc.ncbi.nlm.nih.gov/articles/PMC12838905/

  16. Giovanni Zuliani, Gloria Brombo, Michele Polastri, Tommaso Romagnoli, Gianmarco Mola, Raffaella Riccetti, Davide Seripa, Alessandro Trentini, Carlo Cervellati; "High plasma homocysteine levels predict the progression from mild cognitive impairment to dementia"; Neurochemistry International; 2024 Jul

    https://www.sciencedirect.com/science/article/pii/S0197018624000901

  17. A David Smith, Helga Refsum, Teodoro Bottiglieri, Michael Fenech, Babak Hooshmand, Andrew McCaddon, Joshua W Miller, Irwin H Rosenberg, Rima Obeid; "Homocysteine and Dementia: An International Consensus Statement"; J Alzheimers Dis.; 2018 Feb

    https://pmc.ncbi.nlm.nih.gov/articles/PMC5836397/

  18. Peter Lyon, Victoria Strippoli, Byron Fang, Luisa Cimmino; "B Vitamins and One-Carbon Metabolism: Implications in Human Health and Disease"; Nutrients; 2020 Sep

    https://pmc.ncbi.nlm.nih.gov/articles/PMC7551072/

  19. Zhibin Wang, Wei Zhu, Yi Xing, Jianping Jia, Yi Tang; "B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis"; Nutr Rev.; 2022 Mar

    https://pubmed.ncbi.nlm.nih.gov/34432056/

  20. H Chen, S Liu, B Ge, D Zhou, M Li, W Li, F Ma, Z Liu, Y Ji, G Huang; "Effects of Folic Acid and Vitamin B12 Supplementation on Cognitive Impairment and Inflammation in Patients with Alzheimer's Disease: A Randomized, Single-Blinded, Placebo-Controlled Trial"; J Prev Alzheimers Dis.; 2021

    https://pubmed.ncbi.nlm.nih.gov/34101780/

  21. Rie Kishida, Kazumasa Yamagishi, Koutatsu Maruyama, Ai Ikeda, Mizuki Sata, Mari Tanaka, Chika Okada, Yasuhiko Kubota, Mina Hayama-Terada, Yuji Shimizu, Isao Muraki, Mitsumasa Umesawa, Hironori Imano, Tomoko Sankai, Takeo Okada, Akihiko Kitamura, Masahiko Kiyama, Hiroyasu Iso; "Dietary intake of folate, vitamin B6, vitamin B12, and riboflavin and the risk of incident dementia"; Eur J Clin Nutr.; 2025 Nov

    https://pubmed.ncbi.nlm.nih.gov/40999064/

  22. Shazia Jatoi, Abdul Hafeez, Syeda Urooj Riaz, Aijaz Ali, Muhammad Ishaq Ghauri, Maham Zehra; "Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia"; Cureus; 2020 Feb

    https://pmc.ncbi.nlm.nih.gov/articles/PMC7077099/

  23. Zhibin Wang, Wei Zhu, Yi Xing, Jianping Jia, Yi Tang; "B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis"; Nutr Rev.; 2022 Mar

    https://pubmed.ncbi.nlm.nih.gov/34432056/

  24. Xiaohong Zhang, Guangyi Bao, Debiao Liu, Yu Yang, Xuezhi Li, Gaomei Cai, Yan Liu, Yili Wu; "The Association Between Folate and Alzheimer's Disease: A Systematic Review and Meta-Analysis"; Front Neurosci.; 2021 Apr

    https://pmc.ncbi.nlm.nih.gov/articles/PMC8079632/

  25. Christopher Wong, Fuad Benyaminov, Lauren Block; "Reversible dementia in the setting of multiple medical comorbidities due to B12 deficiency"; BMJ Case Rep.; 2022 Mar

    https://pubmed.ncbi.nlm.nih.gov/35318204/

Katie Stone - Naturopath

About the Author

Katie is a qualified Naturopath (BNatMed) and freelance writer from New Zealand. She specializes in all things health and wellness, particularly dietary supplements and nutrition. Katie is also a dedicated runner and has completed more half-marathons than she can count!

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