Vitamin D, what it is, how do I get it & what does it do?

According to a 2012 study, nearly 50% of the worldwide population is deficient in “Vitamin D” ( 25-hydroxy-Vitamin D or calcidiol), which is technically not a vitamin at all, but is a “pre-hormone”, a biologically inactive glandular secretory product, having little or no biologic activity, that is converted to an active hormone.

Vitamin D is produced in the skin through direct UV light from the sun. Through complex enzymatic processes, it is converted into its usable form.

So why are so many people deficient in it? The authors of that 2012 study attributed deficiency to lifestyle -ie reduced outdoor activities- and environmental effects that reduce exposure to sunlight (like air pollution). Access is another limiting factor, those living north of the latitude of Boston,MA (~40 N) don’t get enough UV light exposure from the sun for vitamin D synthesis through the months of November to early March.

So how else can you get Vitamin D? It can also be consumed in the diet, although very few foods naturally contain vitamin D- fatty fish (mackerel, salmon, sardines), fish liver oils, and eggs from hens that have been fed vitamin D or milk that has been fortified with it. Or, you can supplement with it.

Once consumed or synthesized, vitamin D enters the circulation and is transported to the liver where it is converted to form 25-hydroxyvitamin D (calcidiol; 25-hydroxyvitamin D). This is the major circulating form of vitamin D and a useful indicator of vitamin D nutritional status. This is the form of Vitamin D that is tested in blood tests.

Once active Vitamin D is in our systems, it plays many valuable roles (see Clinical Benefits below) and deficiency can result in a host of symptoms, including muscle weakness and pain, fatigue, painful menses, bone malformation, osteoporosis, chronic illness, diabetes, hypertension, autoimmune diseases and cancer.

To find out if you have adequate Vitamin D levels, make an appointment to come in today. Too often the vague symptoms of Vitamin D deficiency go ignored.

From Nair & Maseeh’s 2012 article in the Journal of Pharmacology & Pharmacotherapeutics

Clinical Benefits of Vitamin D:

Cancer: Vitamin D decreases cell proliferation and increases cell differentiation, stops the growth of new blood vessels, and has significant anti-inflammatory effects. While it may be too soon to say Vitamin D alone is a cancer fighter, we do know it has a role in preventing cell changes that too often contribute to cancer development.

Heart disease & Type 2 diabetes: there is growing evidence that the protective effect of vitamin D on the heart could be via the renin–angiotensin hormone system, through the suppression of inflammation, or directly on the cells of the heart and blood-vessel walls, playing a role in preventing heart disease, hypertension and blood pressure & insulin regulation.

Obesity Low concentrations of circulating vitamin D are common with obesity and may represent a potential mechanism explaining the elevated risk of certain cancers and cardiovascular outcomes.

Depression A Norwegian trial of overweight subjects showed that those receiving a high dose of vitamin D had a significant improvement in depressive symptom scale scores after 1 year versus those receiving placebo.

Cognitive impairment Low levels of 25(OH)D may be especially harmful to executive functions. In an Italian population-based study, low levels of vitamin D were associated with substantial cognitive decline in the elderly population studied during a 6-year period.

Parkinson’s disease Parkinson’s disease is a major cause of disability in the elderly population. Unfortunately, risk factors for this disease are relatively unknown. Recently, it has been suggested that chronically inadequate vitamin D intake may play a significant role in the pathogenesis of Parkinson’s disease.

Fractures and falls Vitamin D is known to help the body absorb calcium, and many studies have shown an association between low vitamin D concentrations and an increased risk of fractures and falls in older adults.Supplementation with about 800 IU of vitamin D per day reduced hip and nonspinal fractures by about 20%. USDA Human Nutrition Research Center on Aging at Tufts University have examined the best trials of vitamin D versus placebo for falls. Their conclusion is that “fall risk reduction begins at 700 IU and increases progressively with higher doses”

Autoimmune diseases deficiency can contribute to autoimmune diseases such as multiple sclerosis (MS), type 1 diabetes, rheumatoid arthritis, and autoimmune thyroid disease.

Influenza  in the winter months vitamin D deficiency may be the seasonal stimulus that triggers influenza outbreaks in the winter

Pelvic floor disorders The frequency of Pelvic floor disorders, including urinary and fecal incontinence, is increasing with age. Pelvic floor disorders have been linked to osteoporosis and low BMD and remain one of the most common reasons for gynaecologic surgery, with a failure rate of 30%. Subnormal levels of 25(OH)D are common among women, and lower levels are associated with a higher likelihood of pelvic floor disorders.

Age-related macular regeneration High vitamin D blood levels appear to be associated with a decreased risk for the development of early age-related macular degeneration (AMD) among women younger than 75 years

Schedule Today to have your Vitamin D levels checked today:



Nair, R., Maseeh,A. “Vitamin D: The “sunshine” vitamin”. J Pharmacol Pharmacother. 2012 Apr-Jun; 3(2): 118–126.

OSU. Linus Pauling Institute. Micronutrient Center: Vitamin D