Vitamin D does not increase calcium absorption in young women: a randomized clinical trial
Gallagher JC, Jindal PS, Smith LM
Published in J Bone Miner Res, Vol. 29 (5), pp. 1081-7
Methodology
Double-blind trial in 198 white and African American women aged 25-45 with 25(OH)D below 20 ng/mL, randomised to vitamin D3 400, 800, 1,600, 2,400 IU a day or placebo for 12 months, with a calcium supplement added to lift intake to about 1,031 mg/day. Calcium absorption measured with radiocalcium.
Key Findings
Mean 25(OH)D rose from 13.4 to 40 ng/mL on 2,400 IU, yet calcium absorption did not increase on any dose and was unrelated to final 25(OH)D. No threshold of low 25(OH)D reduced absorption.
Conclusions
The authors saw no need to recommend vitamin D for increasing calcium absorption in normal subjects.
Limitations
Young, otherwise healthy women with insufficiency rather than severe deficiency, so it does not speak to rickets, malabsorption or hypocalcemia.
Supplements Studied
Vitamin D doses up to 2400 IU daily did not increase calcium absorption
Related Health Concerns
Study Details
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.