Volume 6 · Nº 1 Supl · March 2014
- How to use vitamin D, and what supplementary dose would be the optimum to achieve the best balance between efficacy and security? [1-4]
- Vitamin D deficiency in Spain. Reality or myth? [5-10]
- Extraskeletal effects of vitamin D [11-18]
- Recommendations for the administration of vitamin D. National and international guides [19-22]
- What perception do Spanish doctors have of vitamin D? [23-28]
How to use vitamin D, and what supplementary dose would be the optimum to achieve the best balance between efficacy and security?
Vitamin D is a steroid synthesised in the skin by exposure to sunlight and/or through ingestion of foods which contain it, and it plays a fundamental role in the mineralisation of the bone system at all ages. Vitamin D is not only a nutrient but is also considered to be a true hormone with various functions, a principal one of which is to maintain blood calcium at a physiologically acceptable level for it to carry out its metabolic functions, the transduction of signals and neuromuscular activity .read more
Vitamin D3 (colecalciferol) is formed from its precursor 7-dehydrocholesterol in the skin by ultraviolet irradiation. In the liver the vitamin D3 is hydroxylated to form 25-hydroxyvitamin D3, which is metabolised to its active metabolite 1,25-dihydroxyvitamin D3 preferentially in the kidney. Vitamin D3 may also be provided in the diet, which is a significant source of supply only in the case of insufficient exposure to sunlight. Blue fish naturally contains large quantities of vitamin D3, while other foods contain significant quantities of vitamin D only after being fortified. For fortification, in many countries vitamin D2 is used (ergocalciferol) obtained from vegetable sources .read more
Since it was discovered by McCollum in 1922 how vitamin D was involved in bone mineralisation and was responsible for rickets , much new knowledge has come to light. From being a vitamin it has become considered to be a hormone , and with parathormone and calcitonin makes up the calciotropic hormone group. Its important role in the homeostasis of calcium and its direct action on bone tissue have made it the object of continual research in the study of mineral metabolism.
The D hormone system, in spite of having been known for more than a century, has been ignored until relatively recent years. Proof of this is its still erroneous naming as vitamin D. Since the end of the 1990s, and with the turn of the century, the interest and the potential beneficial effects of its supplementation and/or replacement has increased enormously, moving from a recommendation of a dose which empirically avoids infantile rickets to a recommendation of mega-dosage.read more
The last few years have seen a notable advance in the understanding of practically all the fields of study related vitamin D, which has resulted in it being considered to be a vitamin which is recognised as a steroid hormone [1-4].
Although vitamin D is classically related with bone mineral metabolism, its effects on practically the whole organism, the so-called “extra-bone” effects of vitamin D, are becoming increasingly better understood [2,3,5-8], and which have been reviewed in another article in this Monograph .
In the literature consulted we found scant reference to the opinions of Spanish doctors regarding different aspects of vitamin D in the Spanish population in general or in their patients, their views on desirable levels of vitamin D, and lastly, the dose they would recommend be administered. In this study we would like to make a first approximation of these data, which will allow us to understand what knowledge Spanish doctors have of vitamin D.read more