An unlikely pair: The impact of vitamin D on dementia

As a registered dietitian, it is exciting any time there is emerging research and conversation about nutrition and its relationship to a condition in a new way. Researchers and practitioners are thinking about vitamin D and its relationship to dementia. Before taking steps with practical application, we need to first have a working knowledge of dementia.

What is dementia?

Dementia is a general term describing decline in mental ability severe enough to interfere with daily life. This includes decline in memory, thinking, reasoning, language skills, problem solving, and self-management. Dementia impacts about half of adults 85 years or older with 10 million new cases annually. Dementia currently impacts 50 million people worldwide and is projected to impact 82 million people in 2030. Even with these staggering statistics, it is vital to remember that dementia is not a normal part of aging.

Dementia is caused by progressive damage to neurons or nerve cells in the brain, a process known as neurodegeneration. Some neurodegeneration is normal in the aging process but those with dementia have significantly more damage.

Brain changes likely begin a decade or more before symptoms occur with the underlying mechanism believed to be a build up of proteins in the brain. Dementia is categorized into four subtypes: Alzheimer’s disease, vascular dementia, Lewy body dementia, and frontotemporal dementia. Alzheimer’s disease is the most common type. Alzheimer’s disease is associated with beta-amyloid and tau proteins, vascular dementia is associated with changes in brain blood vessels, Lewy body dementia is associated with alpha-synuclein protein, and frontotemporal dementia leads to abnormal protein build up.

The areas of the brain that have neurodegeneration in dementia leading to dementia symptoms are the hippocampus, hypothalamus, cortex, and subcortex.

The potential role of vitamin D

Vitamin D receptors (VDRs) are present in the neurons & glial cells of the hippocampus, hypothalamus, cortex, and subcortex — the same areas of the brain that impact cognition in dementia. These VDRs can convert calcidiol to calcitriol, effectively activating vitamin D. The presence of these receptors is the key to the proposed connection between vitamin D and dementia.

What does all this mean for the practicing registered dietitian? What does the current evidence suggest when using medical nutrition therapy with dementia patients? Check out Dietitian On Demand’s webinar on Vitamin D and Dementia to dig into the research!

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References:

Byrn, M. A., & Sheean, P. M. (2019). Serum 25(OH)D and Cognition: A Narrative Review of Current Evidence. Nutrients, 11(4), 729.

Sommer, I., Griebler, U., Kien, C., Auer, S., Klerings, I., Hammer, R.,  Gartlehner, G. (2017). Vitamin D deficiency as a risk factor for dementia: a systematic review and meta-analysis. BMC geriatrics, 17(1), 16.

Dementia. (2019). World Health Organization. Retrieved from https://www.who.int/news-room/fact-sheets/detail/dementia

What is Dementia? Symptoms, Types, and Diagnosis (2017). National Institute of Health. Retrieved from: https://www.nia.nih.gov/health/what-dementia-symptoms-types-and-diagnosis

Dementia. (2019). World Health Organization. Retrieved from: https://www.who.int/news-room/fact-sheets/detail/dementia

Plassman B.L., Langa K.M., McCammon R.J., Fisher G.G., Potter G.G., Burke J.R., Steffens D.C., Foster N.L., Giordani B., Unverzagt F.W., Welsh-Bohmer K.A., Heeringa S.G., Weir D.R., Wallace R.B. (2011).  Ann Neurol. 70(3):418-26.

What is Dementia? (2019). Alzheimer’s Association. Retrieved from: https://www.alz.org/alzheimers-dementia/what-is-dementia

What is Dementia? (2019). University of California San Francisco. Retrieved from: https://memory.ucsf.edu/what-dementia

Vitamin D. (2019). National Institute of Health. Retrieved from: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

Landel, V., Annweiler, C., Millet, P, Morello, M., Feron, F. (2016).  Vitamin D, cognition and Alzheimer’s Disease: The therapeutic benefit is in the D-tails. J. Alzheimers Dis, 53, 419–444.

Annweiler, C., Montero-Odasso, M., Llewellyn, D.J., Richard-Devantoy, S., Duque, G., Beauchet, O. (2013). Meta-analysis of memory and executive  dysfunctions in relation to vitamin D. J. Alzheimers Dis. 37, 147–171.