Volume 89, Issue 5, May (2003), pp. 552-572 © The Author 2003
doi:10.1079/BJN2003837

Medline/PubMed Citation | Related Articles in PubMed | Download to Citation Matcher  

Review article

Vitamin D in preventive medicine: are we ignoring the evidence?

Armin Zittermann
Department of Nutrition Science, University of Bonn, Endenicher Allee 11-13, 53115 Bonn, Germany

 (Received 28 January 2002–Revised 22 November 2002–Accepted 28 December 2002)

Vitamin D is metabolised by a hepatic 25-hydroxylase into 25-hydroxyvitamin D (25(OH)D) and by a renal 1α-hydroxylase into the vitamin D hormone calcitriol. Calcitriol receptors are present in more than thirty different tissues. Apart from the kidney, several tissues also possess the enzyme 1α-hydroxylase, which is able to use circulating 25(OH)D as a substrate. Serum levels of 25(OH)D are the best indicator to assess vitamin D deficiency, insufficiency, hypovitaminosis, adequacy, and toxicity. European children and young adults often have circulating 25(OH)D levels in the insufficiency range during wintertime. Elderly subjects have mean 25(OH)D levels in the insufficiency range throughout the year. In institutionalized subjects 25(OH)D levels are often in the deficiency range. There is now general agreement that a low vitamin D status is involved in the pathogenesis of osteoporosis. Moreover, vitamin D insufficiency can lead to a disturbed muscle function. Epidemiological data also indicate a low vitamin D status in tuberculosis, rheumatoid arthritis, multiple sclerosis, inflammatory bowel diseases, hypertension, and specific types of cancer. Some intervention trials have demonstrated that supplementation with vitamin D or its metabolites is able: (i) to reduce blood pressure in hypertensive patients; (ii) to improve blood glucose levels in diabetics; (iii) to improve symptoms of rheumatoid arthritis and multiple sclerosis. The oral dose necessary to achieve adequate serum 25(OH)D levels is probably much higher than the current recommendations of 5–15 μg/d.

Keywords:
Vitamin D insufficiency: Vitamin D intoxication: Parathyroid hormone: Disease prevention