Intestinal calcium absorption as shown by stable strontium test in celiac disease before and after gluten-free diet

To investigate the effect of gluten-free diet on mineral and bone metabolism in women with celiac disease and, using the strontium test, to assess intestinal calcium absorption.

We studied body mass index, biochemical and bone mineral indices, strontium absorption test, and bone mineral density in 18 women (mean age 36.8 yr, range 18-68 yr) with celiac disease at diagnosis and after 12 months of gluten-free diet.

Mean strontium absorption at diagnosis was markedly decreased with respect to control values (13.84 +/- 9.03% vs 22.47 +/- 4.21%, p < 0.0001), and 11 of the 18 patients (61%, subgroup A) had low values. In all patients, mean hemoglobin, serum potassium, magnesium, plasma calcium, urinary calcium, and phosphorus were significantly abnormal at diagnosis, whereas only the subgroup A had significantly reduced body mass index, 25 OH vitamin D, and elevated alkaline phosphatase. This subgroup differed in body mass index (p < 0.003) and calciuria (p < 0.035) with respect to the other patients. Strontium absorption correlated with body mass index, calcemia, and 25 OH vitamin D. After the gluten-free diet, all biochemical variables and strontium absorption normalized (23.23 +/- 5.54%), whereas bone mineral density did not change.

At diagnosis, the patients frequently had intestinal calcium malabsorption, as demonstrated by strontium test, with an early renal compensatory mechanism. After the gluten-free diet, the normalization of calcium absorption and the decrease of mid-molecule parathyroid hormone suggested a normalization of mineral metabolism, although a positive effect on bone mineral density was not evident at that time.