25-Hydroxyvitamin D level does not reflect intestinal calcium absorption: an assay using strontium as a surrogate marker

2014 ◽  
Vol 33 (3) ◽  
pp. 319-328 ◽  
Author(s):  
Marília Brasilio Rodrigues Camargo ◽  
Tatiane Vilaça ◽  
Lilian Fukusima Hayashi ◽  
Olguita G. Ferreira Rocha ◽  
Marise Lazaretti-Castro
Keyword(s):  
Calcium Absorption ◽  
Surrogate Marker ◽  
Intestinal Calcium Absorption ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D

COMPARISON BETWEEN THE 5,6-CIS AND 5,6-TRANS ISOMERS OF 25-HYDROXYVITAMIN D3 IN CHRONIC HYPOPARATHYROIDISM

1977 ◽  
Vol 86 (4) ◽  
pp. 784-793 ◽  
Author(s):  
Gerd Offermann ◽  
Dieter Kraft
Keyword(s):  
Serum Calcium ◽  
Calcium Release ◽  
Calcium Absorption ◽  
Intestinal Calcium Absorption ◽  
Normal Range ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
One Year ◽  
Hydroxyproline Excretion ◽  
Chronic Hypoparathyroidism

ABSTRACT Five patients with chronic post-operative hypoparathyroidism were treated with 450 μg/day 5,6-trans-25-hydroxyvitamin D3 (5,6-trans-25OHD3) for 14 days, and the treatment was continued with 150 μg/day for one year. At the end of this period the patients received 450 μg/day 5,6-cis-25-hydroxyvitamin D3 (5,6-cis-25OHD3) for 14 days. Comparison of the effects of both isomers revealed a similar ability to enhance intestinal calcium absorption and to normalize serum calcium; serum phosphate and alkaline phosphatase, however, remained unaffected. Urinary phosphate and hydroxyproline excretion decreased on the cis-isomer and increased on the trans-isomer. During treatment with the lower dose of 5,6-trans-25OHD3 intestinal calcium absorption remained in the normal range for one year, whereas the serum calcium decreased to the levels observed before administration of 450 μg/day within 6 weeks. The results suggest that in hypoparathyroidism 5,6-cis-25OHD3 and 5,6-trans-25OHD3 are equally effective on serum calcium and on intestinal calcium absorption, but that their mode of action on renal phosphate handling and on calcium release from bone is different.

Vitamin D and Bone Health—Discussion Points Following the Recent Institute of Medicine Recommendations

2011 ◽  
Vol 07 (02) ◽  
pp. 137 ◽  
Author(s):  
Robert P Heaney ◽  
Keyword(s):  
Vitamin D ◽  
Bone Health ◽  
Calcium Absorption ◽  
Institute Of Medicine ◽  
Vitamin D Status ◽  
Extensive Experience ◽  
Hydroxyvitamin D ◽  
Daily Amount ◽  
Fracture Risk Reduction ◽  
25 Hydroxyvitamin D

The 2011 Institute of Medicine recommendations for vitamin D—both the recommended daily amount (RDA) and the vitamin D status judged adequate for bone health—are too low. Calcium absorption, osteoporotic fracture risk reduction, and healing of histological osteomalacia all require values above 30 ng/ml, and probably even 40 ng/ml. Furthermore, the proposed RDA (600 international units per day up to the age of 70) is not compatible with the blood level of 25-hydroxyvitamin D (i.e., 20 ng/ml) recommended in the same report. Concerns regarding adverse consequences of higher intakes or status levels can be dismissed, in view of our extensive experience with outdoor summer workers (who regularly have values of 60 ng/ml or more) and the virtual certainty that human physiology evolved in—and is attuned to—an environment providing 10,000 IU/day or more.

scholarly journals Fermentation of calcium-fortified soya milk does not appear to enhance acute calcium absorption in osteopenic post-menopausal women

2010 ◽  
Vol 105 (2) ◽  
pp. 282-286 ◽  
Author(s):  
Anne Lise Tang Fook Cheung ◽  
Gisela Wilcox ◽  
Karen Z. Walker ◽  
Nagendra P. Shah ◽  
Boyd Strauss ◽  
...  
Keyword(s):  
Calcium Absorption ◽  
Statistical Significance ◽  
Culture Collection ◽  
Normal Serum ◽  
Soya Milk ◽  
Hydroxyvitamin D ◽  
Menopausal Women ◽  
25 Hydroxyvitamin D ◽  
The Mean ◽  
Post Menopausal

Ageing women may choose to drink soya milk to reduce menopausal symptoms. As fermentation enriches soya milk with isoflavone aglycones, its beneficial qualities may improve. To reduce osteoporotic risk, however, soya milk must be Ca enriched, and it is not known how fermentation affects Ca bioavailability. A randomised crossover pilot study was undertaken to compare the Ca absorption of fortified soya milk with that of fermented and fortified soya milk in twelve Australian osteopenic post-menopausal women. The fortified soya milk was inoculated with Lactobacillus acidophilus American Type Culture Collection (ATCC) 4962 and fermented for 24 h at 37°C. Ca absorption from soya milk samples was measured using a single isotope radiocalcium method. Participants had a mean age of 54·8 (sd 12·3) years, with mean BMI of 26·5 (sd 5·5) kg/m2 and subnormal to normal serum 25-hydroxyvitamin D (mean 62·5 (sd 19·1) nmol/l). Participants consumed 185 kBq of 45Ca in 44 mg of Ca carrier. The mean fractional Ca absorption (α) from soya milk and fermented soya milk was 0·64 (sd 0·23) and 0·71 (sd 0·29), respectively, a difference not of statistical significance (P = 0·122). Although fermentation of soya milk may provide other health benefits, fermentation had little effect on acute Ca absorption.

Sign in / Sign up

Export Citation Format

Share Document