Vitamin D Testing

A Highly Specific Assay for Plasma 25(OH) Vitamin D to Assess Its Multiple Roles in Maintaining Optimum Health

Recent cutting-edge reviews by experts in the U.S.1 and Europe2 emphasize the importance of Vitamin D for bone health, immunomodulation, and regulation of cell growth. Vitamin D deficiency and insufficiency are major unrecognized health problems, especially at higher latitudes.

A recent study of the nutritional status of women with osteoporosis found that 39% had vitamin D insufficiency (<15 ng/ml in plasma)3. 25(OH)Vitamin D plasma levels of >20 ng/ml are required to maintain calcium homeostasis, and concentrations of >30 ng/ml may be needed for maximum bone and overall cellular health.

Why Test Vitamin D Levels?

• Prevention and possible treatment of hypertension.4
• Prevention of major cancers including breast, colon and prostate.1
• Evaluation of chronic musculoskeletal pain.
• Prevention of autoimmune diseases including Type 1 diabetes, multiple sclerosis and rheumatoid arthritis.1
• Prevention of osteoporosis and osteomalacia.1

Who’s at Special Risk?

• Elderly, especially shut-ins.
• Non-caucasians.
• Newborns who are breast-fed.
• Regular sun screen users.
• Those living at latitudes north of Los Angeles, Calif.
• Patients receiving Rx drugs, including older antiepileptic drugs, which stimulate metabolic inactivation of Vitamin D.
• Those living under persistent cloud cover.

When Should You Test Vitamin D Levels?

• Dr. Michael F. Holick recommends once a year, preferably in the fall.5
• The Vitamin D Council recommends twice a year, in late October and early April, depending on the latitude, to obtain peak and trough levels.6
• When evaluating patients with or at risk for the disorders listed above.

References:

1 Holick MF. J Cell Biochem. 2003 Feb 1;88(2):296-307.
2 Zittermann A. Br J Nutr. 2003 May;89(5):552-72.
3 Mezquita-Raya P, et. al. J Bone Miner Res. 2001 Aug;16(8):1408-15.
4 Li YC. J Cell Biochem. 2003 Feb 1;88(2):327-31.
5 Hollick MF Nutrition Action Healthletter Dec 2003.
6 Vitamin D Council Web site:www.cholecalciferol-council.com

ADDITIONAL INFORMATION