Potential Indicators

Although having a low level of vitamin D is often asymptomatic, you might experience:

    More frequent infections

    Fatigue

    Muscle or bone discomfort

    Depressed mood

If you have any of the following symptoms that are, or can be, associated with a vitamin D deficiency, then you should consult with your health-care practitioner:

    Muscle spasms and twitching (which can be anywhere but are more common in the face and around the mouth or eyes)

    Generalized weakness

    Loss of balance/falling

    Severe bone and joint pain ‐ hip pain is most common

    Unexplained fracture

    An onset of seizures

    Abnormal heart rate or rhythm

    High blood pressure

Potential signs and symptoms of high vitamin D
Although having a vitamin D level that is too high can be asymptomatic, with a very high level (usually a result of excess calcium absorption) you could experience:

    Anorexia/loss of appetite

    Vomiting

    Diarrhea and/or constipation

    Excessive thirst, dry mouth

    Frequent urination

    Fatigue

    Dizziness

    Muscle cramping/pain/twitching

    Bone pain

    Nerve pain (neuropathy)

    Kidney stones

    Confusion and weakness

    Chest pain, irregular heartbeat

    Elevated blood pressure

    Headaches

    Cough, shortness of breath

If you suspect you might have an excess level of vitamin D (which only occurs with excessive supplementation and is very uncommon), then you should consult with your health-care practitioner.
Vitamin D Test 101

What is Vitamin D

Vitamin D is a fat-soluble "vitamin" ‐ in quotes because it is not technically a vitamin because it can be made in the body when the skin is exposed to sunlight. Vitamin D comes in two forms ‐ D2 and D3. Vitamin D3 includes the amount derived from internal production after your skin is exposed to sunlight, as well as the amount derived from diet and supplementation. Vitamin D2 reflects only what is acquired in the diet or from supplementation but cannot be made in the body. Together, these two biomarkers make up an individual's total vitamin D.

Vitamin D3 is found in significant amounts in only a few foods ‐ primarily fish (especially wild caught salmon and fresh herring). Although it is found primarily in "animal sources," vitamin D3 can also be found in algae. Some foods are fortified with vitamin D3, such as milk, orange juice, and cereals. Vitamin D2 is primarily found in mushrooms grown in a lighted environment. Because of the limited number of foods that vitamin D is found in, supplementation is often necessary to prevent or correct a deficiency. Testing your vitamin D level enables you to know if your body has the optimal level of this important vitamin.

How this biomarker impacts your health

It is estimated that at least 42 percent of U.S. adults have a sub-optimal vitamin D level.

Vitamin D, which is measured as 25-hydroxyvitamin D (25OH-D), is a fat-soluble vitamin that is responsible for multiple biological processes. Vitamin D, which has always been known for its capacity to support the absorption of calcium, has more recently been found to support immune function, a healthy inflammatory response, and muscle function. A low vitamin D level is associated with a higher risk for various chronic health concerns, including osteoporosis, muscle wasting (sarcopenia), heart disease, and diabetes.

Unlike vitamins that must be acquired from outside sources, humans can make vitamin D in their skin following adequate exposure to sunlight ‐ hence its nickname, the "sunshine vitamin." However, because we do not get as much sunlight as our ancestors, and because we might not consume adequate dietary sources of vitamin D, many individuals are at risk for insufficient or deficient vitamin D. A too high level of vitamin D can also occur, but this is much less common and is nearly always associated with excessive supplementation.

Thorne's Vitamin D Test measures total vitamin D, which includes the two common forms of vitamin D ‐ D2 (25OH-D2) and D3 (25OH-D3).

A healthy vitamin D level can be crucial for optimal athletic performance, bone repair after exercise or injury, normal muscle function, healthy immune function, and cardiovascular health. Therefore, it is widely accepted that athletes, compared to non-athletes, should strive to maintain a higher than sufficient level of vitamin D.

Vitamin D is also essential for healthy aging. Low levels not only contribute to bone thinning, but also muscle wasting and increased incidence of falls in the elderly.