Scandinavian Journal of Clinical & Laboratory Investigation
April 2012, Vol. 72, No. S243 , Pages 60-64
Paul Lips
Department of Internal Medicine, Endocrine section, VU University medical center, Amsterdam, The Netherlands
Correspondence: Paul Lips, Department of Internal Medicine, Endocrine section, VU University medical center, Amsterdam, The Netherlands. E-mail: P.Lips at vumc.nl

Probably presented at the Bermeyer Coonference in Garmishpartenkirchen (Germany) in March 2012

A low calcium intake aggravates the consequences of vitamin D deficiency. This suggests an interaction between vitamin D and calcium intake, which is the subject of this review. The active vitamin D metabolite, 1,25-dihydroxyvitamin D (1,25(OH)2D) binds to the vitamin D receptor (VDR) in the intestinal cell and stimulates the active calcium transport from the intestine to the circulation. Vitamin D is not needed for the paracellular transport of calcium, which depends on the calcium gradient.

Active calcium absorption decreases when the serum 25-hydroxyvitamin D (25(OH)D) concentration is <?20 nmol/L.

Studies in the VDR null mouse have demonstrated that bone mineralisation can be restored without vitamin D by a diet very high in calcium and lactose.

Both calcium and vitamin D metabolites can decrease the secretion of parathyroid hormone (PTH) through the calcium sensing receptor and the VDR respectively.

With an increasing serum 25(OH)D concentration up to 100 nmol/L or higher serum PTH is still decreasing. A high calcium intake increases the half life of 25(OH)D.

In patients with primary or secondary hyperparathyroidism, the half life of 25(OH)D is shorter.

Similar interactions between calcium intake and vitamin D status have been shown in rat experiments, generally indicating that a high calcium intake is good for the vitamin D economy.

Clinical trials with vitamin D and/or calcium to decrease fracture incidence generally have shown that trials with vitamin D and calcium had better results than calcium or vitamin D alone.

The effects of these trials also depend on baseline calcium intake, baseline vitamin D status, age and residence.
Trials in institutionalized persons had better results than in independently living elderly.
These results confirm that an interaction exists between calcium and vitamin D.
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See also VitaminDWiki

• All items with Calcium in VitaminDWiki 228 items
• Overview Calcium and Vitamin D which includes the following notional chart

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