Vitamin D has long been known for its role in bone health. Scientists believe that vitamin D deficiency may also increase your risk for chronic illnesses, such as cancer, cardiovascular disease, diabetes, and auto-immune diseases. However, the research on this topic remains inconclusive. Vitamin D is not abundant in food sources, but you can easily obtain adequate vitamin D through sunshine or dietary supplements.
Vitamin D Defined
Vitamin D is a broad term that encompasses different molecules. Cholecalciferol, also called vitamin D-3, is the form that is synthesized in the skin through exposure to sunlight. Ergocalciferol, also known as vitamin D-2, is the form that is synthesized by plants. Vitamin D-2 is not produced by the human body but is found in dietary supplements. Both forms of the vitamin effectively raise the 25-hydroxyvitamin D level in the blood.
Vitamin D from Sunshine
Vitamin D is often called the "sunshine vitamin," and rightfully so. Approximately five to 30 minutes of full sun exposure, twice per week, will likely allow your body to produce all the vitamin D that it needs. However, a lot of factors affect the amount of vitamin D that is synthesized in the skin. Cloud cover, shade, heavy pollution, and using sun block with an SPF of 8 or more are all elements that block the ultraviolet-B rays that are responsible for vitamin D production.
Vitamin D from Supplements
Many Americans do not receive adequate sun exposure on a regular basis, so vitamin D supplementation may be beneficial. Supplements are available as either vitamin D-2 or D-3. Most research suggests that both forms are comparable as far as potency, but in very large doses, D-3 may be slightly more effective. Supplements are most commonly sold as 400 IU or 1,000 IU softgel tablets or in high doses by prescription.
Adequate Amounts
Adequate vitamin D status is most accurately measured by the 25-hydroxyvitamin D level in the blood. Your physician can determine this level with a simple blood test. Deficiency is defined by levels less than 20 ng/mL and levels between 20 and 29 ng/mL are considered insufficient. The Institute of Medicine recommends an intake of 600 IU of vitamin D per day in order to maintain an adequate 25-hydroxyvitamin D level. This amount was increased from 400 IU per day in 2010 based on newer research.
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