Why is Vitamin D Important for Brain Health?
Researchers have discovered certain cells in the brain have receptors for vitamin D that keep the brain healthy and functioning.2,12,13
In animal models of Alzheimer’s disease, activated vitamin D helped clear the brain of amyloid, the toxic protein that can build up and contribute to Alzheimer’s pathology.14,15
In a mouse model of Alzheimer’s disease, vitamin D was shown to support neurogenesis,1 or the formation of new healthy brain cells, which occurs during brain development and may occur in some parts of the brain later in life.
Vitamin D protects against neuro-inflammation and neurodegenerative disorders in animals.16,17
Human studies show that higher vitamin D levels are associated with reduced disability and cognitive impairment following stroke.13
How Vitamin D Protects Brain Function
Vitamin D is demonstrating some impressive brain-protecting roles.
These include supporting growth of new brain cells and encouraging removal of amyloid before it leads to Alzheimer’s.1-3
Low levels of vitamin D are associated with memory loss and increased risk for dementia.3-10
According to mainstream medical standards, 64% of Americans don’t have enough vitamin D to keep tissues functioning at peak capacity.11
Combating vitamin D deficiency isn’t difficult. Low-cost vitamin D supplements are readily available.
References
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Morello M, Landel V, Lacassagne E, et al. Vitamin D Improves Neurogenesis and Cognition in a Mouse Model of Alzheimer’s Disease. Mol Neurobiol. 2018 Aug;55(8):6463-79.
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Groves NJ, McGrath JJ, Burne TH. Vitamin D as a neurosteroid affecting the developing and adult brain. Annu Rev Nutr. 2014;34:117-41.
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Annweiler C, Beauchet O. Vitamin D-mentia: randomized clinical trials should be the next step. Neuroepidemiology. 2011;37(3-4):249-58.
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Annweiler C, Dursun E, Feron F, et al. Vitamin D and cognition in older adults: international consensus guidelines. Geriatr Psychol Neuropsychiatr Vieil. 2016 Sep 1;14(3):265-73.
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Annweiler C, Dursun E, Feron F, et al. ‘Vitamin D and cognition in older adults’: updated international recommendations. J Intern Med. 2015 Jan;277(1):45-57.
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Annweiler C, Rolland Y, Schott AM, et al. Higher vitamin D dietary intake is associated with lower risk of alzheimer’s disease: a 7-year follow-up. J Gerontol A Biol Sci Med Sci. 2012 Nov;67(11):1205-11.
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Beydoun MA, Hossain S, Fanelli-Kuczmarski MT, et al. Vitamin D Status and Intakes and Their Association With Cognitive Trajectory in a Longitudinal Study of Urban Adults. J Clin Endocrinol Metab. 2018 Apr 1;103(4):1654-68.
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Camara AB, de Souza ID, Dalmolin RJS. Sunlight Incidence, Vitamin D Deficiency, and Alzheimer’s Disease. J Med Food. 2018 Mar 22.
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Feart C, Helmer C, Merle B, et al. Associations of lower vitamin D concentrations with cognitive decline and long-term risk of dementia and Alzheimer’s disease in older adults. Alzheimers Dement. 2017 Nov;13(11):1207-16.
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Goodwill AM, Campbell S, Simpson S, Jr., et al. Vitamin D status is associated with executive function a decade later: Data from the Women’s Healthy Ageing Project. Maturitas. 2018 Jan;107:56-62.
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Mitchell DM, Henao MP, Finkelstein JS, et al. Prevalence and predictors of vitamin D deficiency in healthy adults. Endocr Pract. 2012 Nov-Dec;18(6):914-23.
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Harms LR, Burne TH, Eyles DW, et al. Vitamin D and the brain. Best Pract Res Clin Endocrinol Metab. 2011 Aug;25(4):657-69.
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Yalbuzdag SA, Sarifakioglu B, Afsar SI, et al. Is 25(OH)D Associated with Cognitive Impairment and Functional Improvement in Stroke? A Retrospective Clinical Study. J Stroke Cerebrovasc Dis. 2015 Jul;24(7):1479-86.
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Durk MR, Han K, Chow EC, et al. 1alpha,25-Dihydroxyvitamin D3 reduces cerebral amyloid-beta accumulation and improves cognition in mouse models of Alzheimer’s disease. J Neurosci.2014 May 21;34(21):7091-101.
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Ito S, Ohtsuki S, Nezu Y, et al. 1alpha,25-Dihydroxyvitamin D3 enhances cerebral clearance of human amyloid-beta peptide(1-40) from mouse brain across the blood-brain barrier. Fluids Barriers CNS. 2011 Jul 8;8:20.
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Calvello R, Cianciulli A, Nicolardi G, et al. Vitamin D Treatment Attenuates Neuroinflammation and Dopaminergic Neurodegeneration in an Animal Model of Parkinson’s Disease, Shifting M1 to M2 Microglia Responses. J Neuroimmune Pharmacol. 2017 Jun;12(2):327-39.
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Koduah P, Paul F, Dorr JM. Vitamin D in the prevention, prediction and treatment of neurodegenerative and neuroinflammatory diseases. Epma j. 2017 Dec;8(4):313-25.
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Available at: https://alz.org/alzheimers-dementia/what-is-dementia/related_conditions/mild-cognitive-impairment. Accessed August 29, 2018.
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Available at: https://alz.org/alzheimers-dementia/facts-figures. Accessed September 5, 2018.
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Littlejohns TJ, Henley WE, Lang IA, et al. Vitamin D and the risk of dementia and Alzheimer disease. Neurology. 2014 Sep 2;83(10):920-8.
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Assmann KE, Touvier M, Andreeva VA, et al. Midlife plasma vitamin D concentrations and performance in different cognitive domains assessed 13 years later. Br J Nutr. 2015 May 28;113(10): 628-37.
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Annweiler C, Doineau L, Gerigne L, et al. Vitamin D and Subjective Memory Complaint in Community-Dwelling Older Adults. Curr Alzheimer Res. 2018;15(7):664-70.
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Matchar DB, Chei CL, Yin ZX, et al. Vitamin D Levels and the Risk of Cognitive Decline in Chinese Elderly People: the Chinese Longitudinal Healthy Longevity Survey. J Gerontol A Biol Sci Med Sci. 2016 Oct;71(10):1363-8.
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Pavlovic A, Abel K, Barlow CE, et al. The association between serum vitamin d level and cognitive function in older adults: Cooper Center Longitudinal Study. Prev Med. 2018 Aug;113:57-61.
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Available at: http://www.medscape.com/viewarticle/850943. Accessed August 29, 2018.
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Annweiler C, Annweiler T, Montero-Odasso M, et al. Vitamin D and brain volumetric changes: Systematic review and meta-analysis. Maturitas. 2014 May;78(1):30-9.
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Brouwer-Brolsma EM, van der Zwaluw NL, van Wijngaarden JP, et al. Higher Serum 25-Hydroxyvitamin D and Lower Plasma Glucose Are Associated with Larger Gray Matter Volume but Not with White Matter or Total Brain Volume in Dutch Community-Dwelling Older Adults. J Nutr. 2015 Aug;145(8):1817-23.
Vitamin D and Age-Related Cognitive Decline
The differences in loss of cognitive function in people in the same age group are striking, with some experiencing a rapid decline.
Depending on the severity and quickness of the loss, the decline can be diagnosed as either mild cognitive impairment or dementia.
Mild cognitive impairment appears as a decline in memory function and other mental processing skills. This condition is very common, affecting roughly 15%-20% of all individuals 65 years of age and older.18 People with mild cognitive impairment are at high risk for dementia.
Dementia is a contributor to death in the elderly, and Alzheimer’s disease is the most common cause of dementia.
Approximately 10% of those 65 years and older live with Alzheimer’s disease. Over 5 million people in the US suffer from Alzheimer’s, and this number is expected to rise in the years to come.19
What does this have to do with vitamin D? Low vitamin D levels have been associated with deteriorating brain function, and vitamin D levels have consistently been found to be predictive of risk for mild cognitive impairment and dementia.8,9 In fact, the risk of developing dementia is greater in those with vitamin D deficiency.20
One study found that a person’s vitamin D level could predict cognitive problems 13 years later. Those with higher vitamin D levels had less cognitive impairment with better short-term and working memory.21
Several other studies found this same link between lower vitamin D levels and the risk for cognitive impairment.7,22-24 In one of these studies, the risk was more than three times greater for those with the lowest levels of vitamin D.23
Vitamin D levels also appear to be associated with the structure of the brain. Normal age-related decline in brain function is associated with atrophy,25,26 the loss of volume of brain tissue over time.
In one recent study, researchers found that higher vitamin D levels were associated with more beneficial gray matter in older adults.27 Gray matter is the brain tissue where nerve cell bodies reside and form functional connections with other cells. This includes the cerebral cortex, which is the major region of the brain that controls cognition, including executive function, new memory formation, and memory recall.