We know that Vitamin D plays a role in improving your health through many pathways. But one little known benefit of Vitamin D is that it may help you to keep your thinking hat on as you get older. If one analyzes Vitamin D levels compared to cognition, those with higher levels do better.

None of us wants to develop dementia, and particularly Alzheimer’s disease, as we get older. We would prefer to get as old as we can but keep a sharp mind. Thus, what can you do to prevent degeneration of your brain? Well, one thing is to take Vitamin D daily, and lots of it.

A recent publication demonstrated the benefit of taking extra Vitamin D and how higher levels are correlated with lower incidence of Alzheimer’s Disease (AD).[1] The study evaluated a population of people in several parts of the United States: Forsyth County, NC;  Washington County, MD; Pittsburgh, PA; and Sacramento county, CA.

They evaluated 1655 elderly adults who were initially free of dementia starting in 1992. Vitamin D levels were checked from 1992-1993, and they were followed up to 1998-1999. During those 5-6 years, 171 developed dementia or any type, with 102 of these developing AD.

The risk of developing any type of dementia was significantly higher if they had low levels of Vitamin D. They divided the people into 3 groups according to their levels of Vitamin D. Then they determined their relative risk of developing dementia with respect to their Vitamin D levels. These values are in the chart below.

GroupLevel of Vitamin DRelative risk of developing All-Cause DementiaRelative risk of developing Alzheimer’s Dis.
Severely Deficient< 25 nmol/l2.252.22
Deficient25 to 50 nmol/L1.531.69
Sufficient> 50 nmol/l11

Bottomline, what this chart is saying is that if your vitamin D level is in the low range, below 25 nmol/l, you have 2.25 times increased risk of developing dementia from any cause, and 2.22 times increased risk of developing AD as opposed to if your vitamin D level is greater than 50 nmol/L over time.

If your level of vitamin D is in the mid-range, between 25 and 50 nmol/L, you have a 53% and a 69% increase risk of developing All-cause dementia and AD respectively.

Thus, the researcher’s findings demonstrate “a strong association between baseline vitamin D concentrations and the risk of incident all-cause dementia and AD”. Their findings support the hypothesis that vitamin D may be neuroprotective, but you must have sufficient amounts in your blood   over time as protection for developing dementia and AD. This level is at least 50 nmol/L, but higher levels may even be better; they just didn’t study that. However, other studies have shown that higher levels are even more protective for degenerative diseases.[2], [3], [4]

What this means for you is that you should find out what vitamin D level is. This is a simple lab test that can be ordered by your doctor. We at TrueMD do this test regularly on our patients. Then, take vitamin D to get your levels up to >50 mmol/L. Doing so may not only help your brain, but also reduce your risk of manly other degenerative process that occur as you age.

But NOTE: these findings are suggestive of a “protective effect” of vitamin D on your brain. Once you get AD, you can’t turn the clock back and fix it. But you can potentially protect it so take your vitamin D regularly.


[1] Thomas J. Littlejohns, William E. Henley, Iain A. Lang, Cedric Annweiler, Olivier Beauchet, Paulo H.M. Chaves, Linda Fried, Bryan R. Kestenbaum, Lewis H. Kuller, Kenneth M. Langa, Oscar L. Lopez, Katarina Kos, Maya Soni, David J. Llewellyn. Vitamin D and the risk of dementia and Alzheimer disease. Neurology Sep 2014, 83 (10) 920-928; DOI: 10.1212/WNL.0000000000000755

[2] Sharon L. McDonnell , Carole A. Baggerly, Christine B. French, Leo L. Baggerly, Cedric F. Garland, Edward D. Gorham, Bruce W. Hollis, Donald L. Trump, Joan M. Lappe. Breast cancer risk markedly lower with serum 25-hydroxyvitamin D concentrations ≥60 vs <20 ng/ml (150 vs 50 nmol/L): Pooled analysis of two randomized trials and a prospective cohort. June 15, 2018https://doi.org/10.1371/journal.pone.0199265

[3] Lowe LC, Guy M, Mansi JL, Peckitt C, B.liss J, Wilson RG, et al. Plasma 25-hydroxy vitamin D concentrations, vitamin D receptor genotype and breast cancer risk in a UK Caucasian population. Eur J Cancer. 2005;41:1164–1169. pmid:15911240. doi.org/10.1016/j.ejca.2005.01.017

[4] Garland CF, et al. Vitamin D and prevention of breast cancer: Pooled analysis. J of Steroid Biochemistry and Molecular Biology. 103(3–5), March 2007: 708-711. doi.org/10.1016/j.jsbmb.2006.12.007