1
|
Gaffney-Stomberg E, Nakayama AT, Lutz LJ, McClung JP, O'Brien KO, Staab JS. Load carriage exercise increases calcium absorption and retention in healthy young women. J Bone Miner Res 2024; 39:39-49. [PMID: 38630876 DOI: 10.1093/jbmr/zjad003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/16/2023] [Accepted: 12/05/2023] [Indexed: 04/19/2024]
Abstract
Aerobic exercise reduces circulating ionized Ca (iCa) and increases parathyroid hormone (PTH), but the cause and consequences on Ca handling are unknown. The objective of this study was to determine the effects of strenuous exercise on Ca kinetics using dual stable Ca isotopes. Twenty-one healthy women (26.4 ± 6.7 yr) completed a randomized, crossover study entailing two 6-d iterations consisting of either 60 min of treadmill walking at 65% VO2max wearing a vest weighing 30% body weight on study days 1, 3, and 5 (exercise [EX]), or a rest iteration (rest [REST]). On day 1, participants received intravenous 42Ca and oral 44Ca. Isotope ratios were determined by thermal ionization mass spectrometry. Kinetic modeling determined fractional Ca absorption (FCA), Ca deposition (Vo+), resorption (Vo-) from bone, and balance (Vbal). Circulating PTH and iCa were measured before, during, and after each exercise/rest session. Data were analyzed by paired t-test or linear mixed models using SPSS. iCa decreased and PTH increased (P < .001) during each EX session and were unchanged during REST. On day 1, urinary Ca was lower in the EX pool (25 ± 11 mg) compared to REST (38 ± 16 mg, P = .001), but did not differ over the full 24-h collection (P > .05). FCA was greater during EX (26.6 ± 8.1%) compared to REST (23.9 ± 8.3%, P < .05). Vbal was less negative during EX (-61.3 ± 111 mg) vs REST (-108 ± 23.5 mg, P < .05), but VO+ (574 ± 241 vs 583 ± 260 mg) and VO- (-636 ± 243 vs -692 ± 252 mg) were not different (P > .05). The rapid reduction in circulating iCa may be due to a change in the miscible Ca pool, resulting in increased PTH and changes in intestinal absorption and renal Ca handling that support a more positive Ca balance.
Collapse
Affiliation(s)
- Erin Gaffney-Stomberg
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, United States
| | - Anna T Nakayama
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, United States
| | - Laura J Lutz
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, United States
| | - James P McClung
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, United States
| | - Kimberly O O'Brien
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14850, United States
| | - Jeffery S Staab
- Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, United States
| |
Collapse
|
2
|
Coombs CV, Wardle SL, Shroff R, Eisenhauer A, Tang JCY, Fraser WD, Greeves JP, O'Leary TJ. The effect of calcium supplementation on calcium and bone metabolism during load carriage in women: protocol for a randomised controlled crossover trial. BMC Musculoskelet Disord 2023; 24:496. [PMID: 37328859 DOI: 10.1186/s12891-023-06600-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/02/2023] [Indexed: 06/18/2023] Open
Abstract
BACKGROUND Military field exercises are characterised by high volumes of exercise and prolonged periods of load carriage. Exercise can decrease circulating serum calcium and increase parathyroid hormone and bone resorption. These disturbances to calcium and bone metabolism can be attenuated with calcium supplementation immediately before exercise. This randomised crossover trial will investigate the effect of calcium supplementation on calcium and bone metabolism, and bone mineral balance, during load carriage exercise in women. METHODS Thirty women (eumenorrheic or using the combined oral contraceptive pill, intrauterine system, or intrauterine device) will complete two experimental testing sessions either with, or without, a calcium supplement (1000 mg). Each experimental testing session will involve one 120 min session of load carriage exercise carrying 20 kg. Venous blood samples will be taken and analysed for biochemical markers of bone resorption and formation, calcium metabolism, and endocrine function. Urine will be collected pre- and post-load carriage to measure calcium isotopes for the calculation of bone calcium balance. DISCUSSION The results from this study will help identify whether supplementing women with calcium during load carriage is protective of bone and calcium homeostasis. TRIAL REGISTRATION NCT04823156 (clinicaltrials.gov).
Collapse
Affiliation(s)
- Charlotte V Coombs
- Army Health and Performance Research, Army Headquarters, Andover, SP11 8HT, UK
| | - Sophie L Wardle
- Army Health and Performance Research, Army Headquarters, Andover, SP11 8HT, UK
| | - Rukshana Shroff
- Renal Unit, UCL Great Ormond Street Hospital for Children NHS Foundation Trust and Institute of Child Health, London, UK
| | | | | | | | - Julie P Greeves
- Army Health and Performance Research, Army Headquarters, Andover, SP11 8HT, UK
| | - Thomas J O'Leary
- Army Health and Performance Research, Army Headquarters, Andover, SP11 8HT, UK.
| |
Collapse
|
3
|
O'Brien KO, Abrams SA. Using stable isotope tracers to study bone metabolism in children. J Physiol 2018; 597:1311-1319. [PMID: 29869788 DOI: 10.1113/jp275452] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/08/2018] [Indexed: 11/08/2022] Open
Abstract
Skeletal mineralization is initiated in utero and continues throughout childhood and adolescence. During these key periods of the life cycle, calcium retention must increase significantly to provide sufficient mineral for bone deposition and skeletal growth. Stable calcium isotopes have served as a fundamental tool to non-invasively characterize the dynamic changes in calcium physiology that occur from infancy through adolescence. These approaches have helped define the dynamics of calcium absorption and utilization in healthy children and in children with chronic diseases. As data in this area have accumulated, new areas of emphasis are beginning to characterize the determinants of variability in mineral retention, the genetic determinants of bone turnover and calcium flux and the impact of the gut microbiome on whole body and niche specific calcium dynamics. Advances in these areas will help define calcium utilization in paediatric populations and provide information that may be useful in maximizing bone acquisition across this critical phase of the life cycle.
Collapse
Affiliation(s)
| | - Steven A Abrams
- Department of Pediatrics, Dell Medical School at the University of Texas at Austin, Austin, TX, 78723, USA
| |
Collapse
|
4
|
Patterson KY, Veillon C. Stable Isotopes of Minerals as Metabolic Tracers in Human Nutrition Research. Exp Biol Med (Maywood) 2016; 226:271-82. [PMID: 11368418 DOI: 10.1177/153537020122600403] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Enriched stable isotopes used as tracers have proven to be valuable in studies of the absorption and metabolism of minerals. Unlike radioisotopes, they can be used in high-risk population groups such as infants, children, and pregnant or lactating women. Estimates of mineral absorption can be made from the oral administration of a single tracer or from two tracers, one given orally and the other intravenously (IV). It is possible to determine the metabolism of the mineral with modeling based on the amount of the tracer or tracers in different biological samples. One of the key decisions in studies of this type is determining which enriched isotope and what amount to use. An example is given of calculations to estimate and compare the amounts of tracers needed for an absorption study. Methods for calculating the amounts of tracer in oral and IV doses are presented, and limits of detection and quantitation are discussed in terms of percent of enrichment and related to isotope ratio measurement precision. A general review of the use of mass spectrometric instruments for quantifying various stable isotopes is given.
Collapse
Affiliation(s)
- K Y Patterson
- USDA, Beltsville Human Nutrition Research Center, Maryland 20705, USA
| | | |
Collapse
|
5
|
Sirichakwal PP, Kamchansuppasin A, Akoh CC, Kriengsinyos W, Charoenkiatkul S, O'Brien KO. Vitamin D Status Is Positively Associated with Calcium Absorption among Postmenopausal Thai Women with Low Calcium Intakes. J Nutr 2015; 145:990-5. [PMID: 25809682 DOI: 10.3945/jn.114.207290] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/26/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Few data exist on the ability of postmenopausal women to absorb calcium from diets habitually low in calcium. OBJECTIVE The objective of this study was to evaluate fractional calcium absorption from a green leafy vegetable vs. milk in relation to vitamin D status. METHODS We measured fractional calcium absorption from both a dairy- and plant-based source in 19 postmenopausal Thai women (aged 52-63 y) with low calcium consumption (350 ± 207 mg/d) in relation to serum parathyroid hormone (PTH) and serum 25-hydroxyvitamin D [25(OH)D]. Fractional calcium absorption was measured using a triple stable calcium isotope method based on isotope recovery in a 28-h urine collection. Two extrinsically labeled test meals were ingested in random order: a green leafy vegetable (cassia) ingested along with ⁴³Ca or a glass of milk containing ⁴⁴Ca. Women received intravenous ⁴²Ca with the first test meal. RESULTS In 19 postmenopausal women studied (mean age, 56.9 ± 3.4 y), ~95% were 25(OH)D sufficient (≥20 μg/L). Serum 25(OH)D status was positively correlated with fractional absorption from both cassia (P = 0.05, R² = 0.21) and milk (P = 0.03, R² = 0.26). Fractional calcium absorption from cassia was significantly lower than that measured from milk (42.6% ± 12.3% vs. 47.8% ± 12.8%, P = 0.03), but true calcium absorption did not significantly differ (120 ± 35 mg/d vs. 135 ± 36 mg/d). Serum PTH was significantly inversely associated with serum 25(OH)D (P = 0.006, R² = 0.37) even though PTH was not elevated (>65 pg/mL). CONCLUSIONS These findings suggest that vitamin D status is an important determinant of calcium absorption among Thai women with low calcium intakes, and cassia may be a readily available source of calcium in this population. Furthermore, these data indicate that serum 25(OH)D concentrations may affect PTH elevation in postmenopausal women with low calcium intakes.
Collapse
Affiliation(s)
| | | | - Christine C Akoh
- Division of Nutritional Sciences, Cornell University, Ithaca, NY
| | | | | | | |
Collapse
|
6
|
Haron H, Shahar S, O'Brien KO, Ismail A, Kamaruddin N, Rahman SA. Absorption of calcium from milk and tempeh consumed by postmenopausal Malay women using the dual stable isotope technique. Int J Food Sci Nutr 2010; 61:125-37. [PMID: 19995131 DOI: 10.3109/09637480903348080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Assessment of calcium bioavailability from non-dairy foods containing moderate amounts of calcium is especially important in populations that have habitually low dairy consumption. Absorption of calcium from milk and tempeh (a traditional fermented soy product) was compared in a sample of Malay subjects. A randomized, crossover design was utilized to assess calcium absorption in 20 postmenopausal women from either a glass of milk (114 g) or from a meal of tempeh (206 g); each containing 130 mg calcium. At each study of Phase 1 (mid-July) and Phase 2 (mid-August), intravenous (42)Ca and oral (44)Ca were administered and calcium absorption was measured in 24-h urine collections post-dosing; with a 1-month washout period between phases. Absorption of calcium from tempeh did not differ significantly from milk (36.9 +/- 10.6% vs. 34.3 +/- 8.6%, respectively). Due to differences in the calcium content of tempeh, four servings of this product would be needed to get the same amount of absorbed calcium as that obtained from a 4-ounce glass of milk. Tempeh may provide readily available calcium for this population of women at risk for low bone mass.
Collapse
Affiliation(s)
- Hasnah Haron
- Department of Nutrition & Dietetics, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia
| | | | | | | | | | | |
Collapse
|
7
|
Sodium and bone health: impact of moderately high and low salt intakes on calcium metabolism in postmenopausal women. J Bone Miner Res 2008; 23:1477-85. [PMID: 18410231 DOI: 10.1359/jbmr.080408] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
High salt intake is a well-recognized risk factor for osteoporosis because it induces calciuria, but the effects of salt on calcium metabolism and the potential impact on bone health in postmenopausal women have not been fully characterized. This study investigated adaptive mechanisms in response to changes in salt and calcium intake in postmenopausal women. Eleven women completed a randomized cross-over trial consisting of four successive 5-wk periods of controlled dietary intervention, each separated by a minimum 4-wk washout. Moderately low and high calcium (518 versus 1284 mg) and salt (3.9 versus 11.2 g) diets, reflecting lower and upper intakes in postmenopausal women consuming a Western-style diet, were provided. Stable isotope labeling techniques were used to measure calcium absorption and excretion, compartmental modeling was undertaken to estimate bone calcium balance, and biomarkers of bone formation and resorption were measured in blood and urine. Moderately high salt intake (11.2 g/d) elicited a significant increase in urinary calcium excretion (p = 0.0008) and significantly affected bone calcium balance with the high calcium diet (p = 0.024). Efficiency of calcium absorption was higher after a period of moderately low calcium intake (p < 0.05) but was unaffected by salt intake. Salt was responsible for a significant change in bone calcium balance, from positive to negative, when consumed as part of a high calcium diet, but with a low calcium intake, the bone calcium balance was negative on both high and low salt diets.
Collapse
|
8
|
Lynch MF, Griffin IJ, Hawthorne KM, Chen Z, Hamzo M, Abrams SA. Calcium balance in 1-4-y-old children. Am J Clin Nutr 2007; 85:750-4. [PMID: 17344496 DOI: 10.1093/ajcn/85.3.750] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Few calcium balance data are available from young children on which to base dietary recommendations. OBJECTIVE The objective of the study was to evaluate the relation between calcium intake and balance in healthy children aged 1-4 y consuming typical American diets. DESIGN Subjects were assigned to a diet with nutrient intakes similar to those of their usual diet. Calcium absorption was assessed by using a dual-tracer stable-isotope technique. Endogenous fecal excretion was measured in a subset of children, and net calcium balance was calculated. RESULTS Mean calcium intake was 551 mg/d (range: 124-983 mg/d), and mean (+/-SEM) calcium retention was 161 +/- 17 mg/d. Both linear and nonlinear modeling of balance data showed that a calcium intake of approximately 470 mg/d led to calcium retention of 140 mg/d, which is the amount that meets expected bone growth needs in children of this age. No evidence was found that calcium intakes of 800 to 900 mg/d reached the threshold intake beyond which no additional increase in calcium retention would occur. CONCLUSIONS Bone growth needs in 1-4-y-old children following American diets are met by a daily calcium intake of approximately 470 mg/d, which suggests that the current Adequate Intake of 500 mg/d is close to the actual Estimated Average Requirement. The benefits and risks of higher calcium intakes consistent with threshold values should be evaluated in a controlled trial before those intakes could be used as a basis for dietary recommendations.
Collapse
Affiliation(s)
- Mary Frances Lynch
- US Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030, USA
| | | | | | | | | | | |
Collapse
|
9
|
Teramoto F, Rokutan K, Sugano Y, Oku K, Kishino E, Fujita K, Hara K, Kishi K, Fukunaga M, Morita T. Long-term administration of 4G-beta-D-galactosylsucrose (lactosucrose) enhances intestinal calcium absorption in young women: a randomized, placebo-controlled 96-wk study. J Nutr Sci Vitaminol (Tokyo) 2007; 52:337-46. [PMID: 17190104 DOI: 10.3177/jnsv.52.337] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study determined the effect of long-term administration of 4(G)-beta-D-galactosylsucrose (lactosucrose; LS) on intestinal calcium absorption. In a randomized, single-blind, parallel-group study, LS (n=9, 6.0 g twice daily) or a placebo (maltose; n=8, 6.0 g twice daily) was administered to healthy young women for 92 wk: the study also included a 4-wk post-administration period. All participants completed the study. Dietary nutrient intake; fecal weight, pH, and moisture content; fecal concentrations of short-chain fatty acids (SCFA), putrefactive products, ammonia, and minerals (calcium, magnesium, phosphorus, and iron); and serum calcium and osteocalcin concentrations were measured every 24 wk. Urinary pyridinoline (PYR) and deoxypyridinoline (DPD), and urinary calcium excretion were measured every 12 wk. Significant effects of oligosaccharide treatment, time, and the interaction between oligosaccharide treatment and time were observed for fecal pH, SCFA, ammonia, and putrefactive product values (p<0.05). Fecal pH, ammonia, and putrefactive product values decreased in the LS group, and the fecal SCFA concentration significantly increased during the administration period; these changes were not observed 4 wk post-administration. To examine the mineral balance of calcium, magnesium, and phosphorus in detail, all the participants completed a 6-d mineral balance study, sometime between week 56 and 60 of the longer study. During the mineral balance study, the daily calcium intake was set at 400 mg; all feces and urine were collected each day for 6 d after an 8-d acclimation period. In the balance study, fecal calcium excretion was significantly lower in the LS group than in the placebo group (p<0.05), and apparent calcium absorption and retention, apparent magnesium and phosphorus absorption, and magnesium retention were significantly higher in the LS group than in the placebo group (p<0.05). Our results suggest that the administration of LS produces a long-term enhancement of intestinal calcium absorption in healthy young women with lower than recommended calcium intakes.
Collapse
Affiliation(s)
- Fusako Teramoto
- Department of Clinical Nutrition, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Winzenberg TM, Shaw K, Fryer J, Jones G. Calcium supplementation for improving bone mineral density in children. Cochrane Database Syst Rev 2006; 2006:CD005119. [PMID: 16625624 PMCID: PMC8865374 DOI: 10.1002/14651858.cd005119.pub2] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Clinical trials have shown that calcium supplementation in children can increase bone mineral density (BMD) although this effect may not be maintained. There has been no quantitative systematic review of this intervention. OBJECTIVES . To determine the effectiveness of calcium supplementation for improving BMD in children. . To determine if any effect varies by sex, pubertal stage, ethnicity or level of physical activity, and if any effect persists after supplementation is ceased. SEARCH STRATEGY We searched CENTRAL, (Cochrane Central Register of Controlled Trials) (Issue 3, 2005), MEDLINE (1966 to 1 April 2005), EMBASE (1980 to 1 April 2005), CINAHL (1982 to 1 April 2005), AMED (1985 to 1 April 2005), MANTIS (1880 to 1 April 2005) ISI Web of Science (1945 to 1 April 2005), Food Science and Technology Abstracts (1969 to 1 April 2005) and Human Nutrition (1982 to 1 April 2005). Conference abstract books (Osteoporosis International, Journal of Bone and Mineral Research) were hand-searched. SELECTION CRITERIA Randomised controlled trials of calcium supplementation (including by food sources) compared with placebo, with a treatment period of at least 3 months in children without co-existent medical conditions affecting bone metabolism. Outcomes had to include areal or volumetric BMD, bone mineral content (BMC), or in the case of studies using quantitative ultrasound, broadband ultrasound attenuation and ultrasonic speed of sound, measured after at least 6 months of follow-up. DATA COLLECTION AND ANALYSIS Two authors independently assessed trial quality and extracted data including adverse events. We contacted study authors for additional information. MAIN RESULTS The 19 trials included 2859 participants, of which 1367 were randomised to supplementation and 1426 to placebo. There was no heterogeneity in the results of the main effects analyses to suggest that the studies were not comparable. There was no effect of calcium supplementation on femoral neck or lumbar spine BMD. There was a small effect on total body BMC (standardised mean difference (SMD) +0.14, 95% CI+0.01, +0.27) and upper limb BMD (SMD +0.14, 95%CI +0.04, +0.24). Only the effect in the upper limb persisted after supplementation ceased (SMD+0.14, 95%CI+0.01, +0.28). This effect is approximately equivalent to a 1.7% greater increase in supplemented groups, which at best would reduce absolute fracture risk in children by 0.1-0.2%per annum. There was no evidence of effect modification by baseline calcium intake, sex, ethnicity, physical activity or pubertal stage. Adverse events were reported infrequently and were minor. AUTHORS' CONCLUSIONS While there is a small effect of calcium supplementation in the upper limb, the increase in BMD which results is unlikely to result in a clinically significant decrease in fracture risk. The results do not support the use of calcium supplementation in healthy children as a public health intervention. These results cannot be extrapolated to children with medical conditions affecting bone metabolism.
Collapse
Affiliation(s)
- T M Winzenberg
- University of Tasmania, Menzies Resarch Institute, Private Bag 23, Hobart, TAS, Australia, 7001.
| | | | | | | |
Collapse
|
11
|
Merki-Feld GS, Neff M, Keller PJ. A 2-year prospective study on the effects of depot medroxyprogesterone acetate on bone mass-response to estrogen and calcium therapy in individual users. Contraception 2003; 67:79-86. [PMID: 12586317 DOI: 10.1016/s0010-7824(02)00460-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The primary aim of this prospective 2-year follow-up study was to investigate the effect of depot medroxyprogesterone acetate (DMPA) on the maintenance of bone mass in women aged 30-45 years. The effects of estrogen or calcium substitution during the second year of follow-up was investigated in seven DMPA users with a high annual bone loss during the first year. The bone mass of 35 users of DMPA and 10 women without hormonal contraception was investigated using peripheral quantitative computed tomography. The baseline cortical and trabecular bone mass (TBM) and the annual change was not different in DMPA users and controls. Over 24 months we measured an increase in TBM of 0.6% and a decrease in cortical bone mass of 0.1% in exposed women. Some but not all of the DMPA users with a bone loss during the first year could be successfully treated with estradiol or calcium. In conclusion, we did not observe an accelerated bone loss in DMPA users aged 30-45 years.
Collapse
Affiliation(s)
- Gabriele S Merki-Feld
- Department of Gynecology and Obstetrics, University Hospital, CH-8091, Zurich, Switzerland.
| | | | | |
Collapse
|
12
|
Wastney ME, Martin BR, Bryant RJ, Weaver CM. Calcium Utilization in Young Women: New Insights from Modeling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 537:193-205. [PMID: 14995037 DOI: 10.1007/978-1-4419-9019-8_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Meryl E Wastney
- Metabolic Modeling Services Ltd., Hamilton 2030, Dalesford, New Zealand.
| | | | | | | |
Collapse
|
13
|
Weaver CM, Liebman M. Biomarkers of bone health appropriate for evaluating functional foods designed to reduce risk of osteoporosis. Br J Nutr 2002; 88 Suppl 2:S225-32. [PMID: 12495464 DOI: 10.1079/bjn2002687] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Osteoporosis is a growing global problem. The health care costs and decreased productivity and quality of life are staggering. Much research is invested in life-style approaches to build peak bone mass during growth to prevent osteoporosis as well as to treat the disease in later life. Functional foods have enjoyed a niche in bone health. Foods fortified with Ca are most popular. Other bone nutrients such as vitamin D, Mg and vitamin K are sometimes added. Future products are likely to include enhancers of Ca absorption such as inulin or whey proteins. Dietary factors that reduce urinary Ca loss (plant proteins) or suppress bone resorption (possibly phyto-oestrogens) are also gaining attention. Methodologies for evaluating the effectiveness of functional foods on bone health include measures of bone quality such as bone densitometry or measures of Ca metabolism, particularly absorption. Biochemical markers for bone turnover are less satisfactory for diet-related effects. Use of a rare isotope, 41Ca, and accelerator mass spectrometry offers a new approach for assessing the ability of functional foods to suppress bone resorption.
Collapse
Affiliation(s)
- Connie M Weaver
- Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907-1264, USA.
| | | |
Collapse
|
14
|
Moser-Veillon PB, Mangels AR, Vieira NE, Yergey AL, Patterson KY, Hill AD, Veillon C. Calcium fractional absorption and metabolism assessed using stable isotopes differ between postpartum and never pregnant women. J Nutr 2001; 131:2295-9. [PMID: 11533269 DOI: 10.1093/jn/131.9.2295] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Determining the fractional absorption (FA) of calcium using the incorporation into urine of stable isotopes given intravenously (IV) and orally has become a routine procedure. We investigated the FA of calcium in two groups of (2-3 mo) postpartum women lactating (LACT) (n = 6) and nonlactating (PPNL) (n = 6), and in never pregnant (NP) women (n = 7). The women consumed a controlled diet containing 30-33 mmol/d calcium (Ca) for 21 d. On d 7 of the controlled diet, the women received 0.05 mmol of 42Ca IV and 0.25 mmol 44Ca orally in milk. Urine samples (24-h) were collected for the next 14 d and morning blood samples were collected from fasting subjects before dosing and at 24 and 48 h after receiving the isotopes. Milk samples from the LACT women were collected from each feeding beginning 24 h before to 72 h after dosing. There were no significant differences in the FA of calcium as measured by stable isotope incorporation into urine (23.8 +/- 2.9%), serum (24.0 +/- 3.4%) or milk (23.6 +/- 3.6%) of LACT women. The fractional calcium absorption measured in urine of the postpartum women (LACT and PPNL, 23.8 +/- 2.9% and 25.0 +/- 3.3%, respectively) did not differ but was greater (P < 0.028) than that of the NP women (17.3 +/- 1.3%). The postpartum LACT and PPNL women had a reduced urinary excretion of calcium (P < 0.01) compared with the NP women. There was a significantly greater incorporation (P < 0.001) by LACT women of the oral isotope dose into milk than into urine. Calcium FA can be determined from incorporation of stable isotopes into breast milk and serum as well as urine.
Collapse
Affiliation(s)
- P B Moser-Veillon
- Department of Nutrition and Food Science, University of Maryland, College Park, 20742, USA.
| | | | | | | | | | | | | |
Collapse
|
15
|
Affiliation(s)
- C M Weaver
- Department of Foods and Nutrition, Purdue University, West Lafayette, Indiana 47907-1264, USA.
| |
Collapse
|
16
|
Abstract
Adequate mineral intake is a crucial part of a healthy diet for children-it supports appropriate growth and development and provides protection against childhood conditions like anemia and helps to prevent future adult diseases such as osteoporosis. Challenges in performing and interpreting studies in infants and children have hampered the accurate assessment of their mineral utilization. Many of the most powerful techniques used in adults, such as radioisotope testing, are not appropriate for use in children. In recent years, advanced mineral stable-isotope techniques have been developed to fill this gap. Pediatric applications include studies of calcium absorption and kinetics during puberty and evaluation of the calcium-iron interaction in infants and toddlers. The effects of genetics in determining calcium absorption and bone turnover may become an important research area. The goals and methods of ongoing mineral stable-isotope research in infants and children are examined in this report. In the past, the cost and difficulties in obtaining isotopes have limited such research. This situation has improved considerably, although relatively few nutrition research laboratories are prepared to perform sample analyses.
Collapse
Affiliation(s)
- S A Abrams
- US Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center and Section of Neonatology, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston 77030-2600, USA.
| |
Collapse
|
17
|
Skulan J, DePaolo DJ. Calcium isotope fractionation between soft and mineralized tissues as a monitor of calcium use in vertebrates. Proc Natl Acad Sci U S A 1999; 96:13709-13. [PMID: 10570137 PMCID: PMC24129 DOI: 10.1073/pnas.96.24.13709] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Calcium from bone and shell is isotopically lighter than calcium of soft tissue from the same organism and isotopically lighter than source (dietary) calcium. When measured as the (44)Ca/(40)Ca isotopic ratio, the total range of variation observed is 5.5 per thousand, and as much as 4 per thousand variation is found in a single organism. The observed intraorganismal calcium isotopic variations and the isotopic differences between tissues and diet indicate that isotopic fractionation occurs mainly as a result of mineralization. Soft tissue calcium becomes heavier or lighter than source calcium during periods when there is net gain or loss of mineral mass, respectively. These results suggest that variations of natural calcium isotope ratios in tissues may be useful for assessing the calcium and mineral balance of organisms without introducing isotopic tracers.
Collapse
Affiliation(s)
- J Skulan
- Department of Geology and Geophysics, University of Wisconsin, Madison, WI 53706, USA.
| | | |
Collapse
|
18
|
Bryant RJ, Cadogan J, Weaver CM. The new dietary reference intakes for calcium: implications for osteoporosis. J Am Coll Nutr 1999; 18:406S-412S. [PMID: 10511321 DOI: 10.1080/07315724.1999.10718905] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The new Dietary Reference Intakes (DRI) for calcium were released August 13, 1997 by the Food and Nutrition Board of the National Academy of Science. Unlike the RDA's which established the minimal amounts of nutrients needed to be protective against possible deficiency, the new values are designed to reflect the latest understanding about nutrient requirements directed at optimizing health in individuals and groups. Adequate calcium intake recommendations were set at levels associated with desirable retention of body calcium since high bone density is known to be less susceptible to fractures. Recommended intake for adults is 1000 to 1200 mg/day. The majority of people do not consume these levels of calcium. The upper tolerable limit for calcium was set at 2.5 g/day.
Collapse
Affiliation(s)
- R J Bryant
- Purdue University, West Lafayette, Indiana 47907-1264, USA
| | | | | |
Collapse
|