Vitamin D: The Versatile Nutrient

Dr. Lynn Toohey, Ph.D, Nutrition

Colorado State University in Ft. Collins, CO

It has been over a decade now since my first newsletter on vitamin D, called “Vitamin D: Discovering New Uses”. In that newsletter, I mentioned some of the various conditions for which vitamin D was gaining recognition (beyond increasing calcium/bone growth), including: Immune support (especially autoimmune disorders and cancer research), cardiovascular disease, skin disorders, nerve cell development (vitamin D is needed for NGF (nerve growth factor), peripheral neuropathy, polycystic ovarian syndrome, etc. It seems that newsletter title could easily be used again today, as vitamin D is still in the news and still constantly being regarded as the vitamin that surprises us with purported benefits, and discovered new uses.
After receiving some correspondence from a respected colleague (Dr. Deed Harrison) on the connection of vitamin D and the brain/dementia, I decided to write this article about vitamin D in the current news.

Vitamin D and the Brain
The observational evidence shows that low serum vitamin D levels are associated with increased risk for cardiovascular diseases, diabetes mellitus, depression, dental caries, osteoporosis, and periodontal disease, all of which are either considered risk factors for dementia or have preceded incidence of dementia.
One developing hypothesis about how vitamin D affects brain development is through bone morphogenetic proteins (BMP); vitamin D increases BMP, which trigger stem cells to differentiate into many different types of cells, including brain cells.1

In a study of 318 elderly participants, vitamin D insufficiency and deficiency was associated with all-cause dementia, Alzheimer disease, stroke (with and without dementia symptoms), and MRI indicators of cerebrovascular disease. The researchers proposed that the findings suggest a potential vasculoprotective role of vitamin D.2

Furthermore, a recent systematic review, while recognizing that the association between serum vitamin D concentrations and cognitive performance needs to be more clearly established, pointed out that three separate quality studies have found four significant positive associations between serum vitamin D concentrations and global cognitive functions.3

Vitamin D and Pregnancy
Scientific evidence suggests that that vitamin D deficiency may not only contribute to the risk of developing a wide range of common chronic diseases, but that the favorable biological effects of vitamin D that contribute to the improvement of human health in humans may be even more critical during pregnancy.

It appears that vitamin D insufficiency during pregnancy is potentially associated with increased risk of preeclampsia, insulin resistance and gestational diabetes mellitus. Furthermore, experimental data also anticipate that vitamin D sufficiency is critical for fetal development, and especially for fetal brain development and immunological functions. “Vitamin D deficiency during pregnancy may, therefore, not only impair maternal skeletal preservation and fetal skeletal formation but also be vital to the fetal "imprinting" that may affect chronic disease susceptibility soon after birth as well as later”.4

Vitamin D and Mood
“Recent findings from a randomized trial suggest that high doses of supplemental vitamin D may improve mild depressive symptoms”, and researchers are trying to determine a) how vitamin D may affect monoamine function and hypothalamic-pituitary-adrenal axis response to stress, b) whether vitamin D supplementation can improve mood in individuals with moderate-to-severe depression, and c) whether vitamin D sufficiency is protective against incident depression and recurrence.5

Vitamin D and P. Neuropathy
“These results suggest that active vitamin D3 could treat peripheral neuropathy by inducing NGF (nerve growth factor) production in the skin”.6
Besides nerve growth factor, vitamin D3 regulates the expression of several other growth factors that influence important pathways in the body. These factors include: insulin-like growth factor (IGF), neurotrophic factor, hepatocyte (liver cell) growth factor, and vascular endothelial growth factor (blood vessel wall lining). These growth factors are present in many areas of the body that are vitamin D-sensitive organs.

Vitamin D and MS/Cancer
Vitamin D and MS/Cancer correlations and relationships are areas of my personal research; these are topics for my next article, as they need an article dedicated to these specific conditions. Thus next time, I will discuss some of the articles I’ve written on MS7 and also the grant I’ve co-written with Immunologist Dr. Don Bellgrau, concerning the nutritional influences of vitamin D on dendritic cells and tumor antigen presentation.8
“Results from ecological, case-control and cohort studies have shown that vitamin D reduces the risk of bone fracture, falls, autoimmune diseases, type 2 diabetes, CVD and cancer”.9

Vitamin D and lupus (SLE) and fibromyalgia:
Many patients with systemic lupus erythematosus (SLE) and fibromyalgia (FM) may spend less time exposed to the sun than healthy individuals and thus might have low vitamin D levels. When studied, half the SLE and FM patients had vitamin D levels < 50 nmol/l, a level at which parathyroid (PTH) stimulation occurs. If PTH stimulation occurs, calcium will be drawn from the bone, and risk for osteoporosis will increase.

Additionally, hydroxychloroquine (HCQ) is a drug sometimes used in these patients, and data from a study “suggest that in SLE patients HCQ might inhibit the conversion to the active form of vitamin D10”.

Vitamin D is both a hormone and a vitamin. Supplementation should be with the active vitamin D3; 15 minutes of sun exposure 3 X week is adequate for most people, although logistics and concerns about skin cancer make supplementation a viable option. Recommended doses for vitamin D have been changing as the benefits of supplementation have become evident; however, it is prudent to treat this fat-soluble vitamin with respect.

Although when I received my PhD the upper limit was set at 2000-2400 IUs per day, dosages these days sometimes run into thousands more IUs per day. The caution would be that it is wise to monitor with lab tests (serum calcium or vitamin D), especially for liability purposes, since the RDIs and upper limits have not technically been changed yet. Blood calcium is tightly regulated, and increases are a major concern. Vitamin D supplementation is contraindicated in sarcoidosis, and although uncommon, can cause hypercalcemia.

1. Chen HL, Panchision DL. Stem Cells 2007; Vol. 25, no. 1: 63–68.
2. Buell JS, Dawson-Hughes B, et al. Neurology. 2009 Nov 25.
3. Annweiler C, Allali G, et al. Eur J Neurol. 2009 Oct;16(10):1083-9.
4. Lapillonne A. Med Hypotheses. 2010 Jan;74(1):71-5.
5. Bertone-Johnson ER. Nutr Rev. 2009 Aug;67(8):481-92.
6. Fukuoka M, et al. Skin Pharmacol Appl Skin Physiol 2001 Jul-Aug;14(4):226-33.
7. Toohey, L. J Brit Soc Allergy Env & Nutr Med 2005.
8. Bellgrau, D & Toohey, L. ACIR grant, 2009.
9. Wang S. Nutr Res Rev. 2009 Dec;22(2):188-203.
10. Huisman AM et al. J Rheumatol 2001 Nov;28(11):2535

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