Vitamin D Testing

Vitamin D Testing at Seattle Naturopathic Center

Why are Naturopaths concerned about Vitamin D levels?

Because depending on where you live, you might be not getting an adequate amount of sunshine to produce powerful Vitamin D.

About Vitamin D

Vitamin D was discovered in the 1900s, during the Industrial Revolution. Rickets, a condition causing weakened bones and bowed legs in children, was found to be due to a deficiency of Vitamin D. In fact, Vitamin D is both a vitamin and a hormone.

Two Ways to Get Your Vitamin D

The first way is through exposure of the skin to ultraviolet light (sunshine), which allows the skin to produce Vitamin D3, also called cholecalciferol. Cholecalciferol is converted by the liver and then by the kidneys to the active form of Vitamin D, which has health-promoting and hormonal benefits. Many factors can inhibit the production of Vitamin D from sunlight exposure. Of course, as concerns for skin cancer have risen, so has the usage of sunscreen. 10,000-25,000 IU of Vitamin D can be produced daily with full-body exposure to sunlight. However, almost all of the UVB rays are blocked by SPF 8 or higher sunscreen, thus preventing adequate production of Vitamin D.

The second way to obtain Vitamin D is orally, through diet or nutritional supplementation. Unfortunately, Vitamin D is rather difficult to obtain from foods. Dairy and cod liver oil are two good sources, but these would still have to be consumed in very large amounts in order to get adequate Vitamin D.

Vitamin D Deficiency and Supplementation

There are many health benefits and preventive health advantages of Vitamin D supplementation. There is also ample evidence that Vitamin D deficiency is more widespread than was previously thought. The following outlines some research on Vitamin D deficiency and related conditions.

Hypertension and Heart Disease

High blood pressure and heart attacks are more common in winter months and in locations farther away from the equator (i.e. areas where sunlight is less abundant). Vitamin D is known to lower a blood pressure-raising substance in the body called angiotensin II. If your blood 25-OH-Vitamin D levels are lower than 34 ng/ml, your risk of heart attack is doubled, compared to people whose levels are above 34. Thus, people with higher blood levels of Vitamin D have naturally lower blood pressures.


Low sunlight exposure and low vitamin D status is associated with increase risk of dying of numerous cancers including breast, ovarian, uterine, prostate, stomach, bladder, and lung cancers and non-Hodgkin’s lymphoma. The researcher who made this connection suggested that 23,000 American lives could be saved yearly by adequate sunlight exposure and/or Vitamin D supplementation.


Studies showed knee and hip arthritis worsened faster in patients with 25-OH-vitamin D levels below 30 ng/ml.


Studies show that Vitamin D supplementation is equally or more successful in treating Seasonal Affective Disorder than use of lightbox therapy.

Pain: Migraines and Musculoskeletal pain

Women with migraines who test as deficient in vitamin D often have an improvement in their migraines if they begin taking vitamin D and calcium daily. Several studies showed that patients with persistent musculoskeletal pain and low back pain had vitamin D deficiency and their pain improved when they took vitamin D supplements.

Polycystic Ovary Syndrome and Infertility

Calcium and Vitamin D supplementation helped all the patients with PCOS and infertility after vitamin D deficiency in one small study.

Multiple Sclerosis

It has long been noted that this autoimmune condition occurs more often at temperate zones, where there is less sunlight exposure. One study showed that calcium, magnesium and vitamin D supplementation helped reduce exacerbations in MS patients. Some researchers and clinicians wonder if supplementation with vitamin D could prevent MS in people living in temperate zones.

Other conditions

Diabetes, insulin resistance, epilepsy, Graves disease, ankylosing spondylitis, systemic lupus erythematosus, obesity, and rheumatoid arthritis are some other conditions that have been associated with deficiency of vitamin D and/or improvement with vitamin D supplements.

Your vitamin D level can be easily assessed with a simple blood test. More information about vitamin D is available on Dr. Lee’s blog

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