Fractional Calcium Absorption
Conditions
Keywords
Triple Stable Isotope
Brief summary
Adequate calcium absorption is essential for reducing one's risk of developing osteoporosis. However, postmenopausal Thai women consume diets which are habitually low in calcium due to lactose intolerance and dietary patterns which typically do not include milk-based products. The primary goal of this study is to measure the fractional calcium absorption from milk and a commonly ingested green leafy vegetable (cassia) in postmenopausal Thai women with habitually low calcium intakes. The secondary objective is to determine associations between calcium absorption and biomarkers which impact vitamin D status and bone metabolism.
Detailed description
Postmenopausal Thai women (n=22) will be recruited from the community surrounding Bangkok and Nakhon Pathon, Thailand. They will be invited to participate in an isotope study comparing the fractional calcium absorption from milk and cassia. Upon arrival, a fasting blood sample will be drawn on the morning of the absorption study to analyze serum markers of vitamin D and bone metabolism (25-hydroxy vitamin D \[25OHD\], parathyroid hormone \[PTH\], and beta-crossLaps) and to determine their impact on calcium absorption. Following this blood draw, women will receive a stable calcium isotope (42Ca) intravenously. Then for breakfast and lunch respectively, the women will be randomly assigned to orally ingest a stable calcium isotope from either the milk (44Ca) or cassia (43Ca) test meals. On day two, women will receive a breakfast, snack, and lunch meal. Urine samples will be collected over the entire 28 hour period and the 24-hr urine collection will be used to measure urinary calcium concentration and to calculate fractional calcium absorption.
Interventions
None listed
Sponsors
Ramathibodi Hospital
Cornell University
Study design
Observational model
CASE_CROSSOVER
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
FEMALE
Age
53 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy * At least 3 years postmenopausal
Exclusion criteria
* Diagnosed gastrointestinal or metabolic diseases known to interfere with calcium absorption and metabolism * Women taking medications (including thiazide diuretics, hormonal replacement therapy, etc.) within two months prior to the study * Women taking dietary supplements within two months prior to the study
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fractional calcium absorption | 24 hours after the ingestion of the second test meal | Urine samples will be collected over s 28 hour period post-dosing with collection ending 24 hours after the ingestion of the second test meal. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| The concentration of 25-hydroxy vitamin D (25OHD) in serum | Upon entry to the study, a 10 mL blood sample will be collected in a less than 2 hour time period. | A fasting 10 mL blood sample will be collected upon entry into the study and used for determining the concentration of 25OHD in serum. |
| The concentration of parathyroid hormone (PTH) in serum | Upon entry to the study, a 10 mL blood sample will be collected in a less than 2 hour time period. | A fasting 10 mL blood sample will be collected upon entry into the study and used for determining the concentration of PTH in serum. |
| The concentration of beta-crossLaps in serum | Upon entry to the study, a 10 mL blood sample will be collected in a less than 2 hour time period. | A fasting 10 mL blood sample will be collected upon entry into the study and used for determining the concentration of beta-crossLaps in serum. |
Countries
United States
Outcome results
None listed