Magnesium, Calcium and Osteoporosis

CONCLUSION:


#19

Cola beverage consumption induces bone mineralization reduction in ovariectomized rats.

Garcia-Contreras F, Paniagua R, Avila-Diaz M, Cabrera-Munoz L, Martinez-Muniz I, Foyo-Niembro E, Amato D.Arch Med Res 2000 Jul-Aug;31(4):360-5

Unidad de Investigacion Medica en Enfermedades Nefrologicas, Hospital de Especialidades, Mexico, D.F., Mexico. dantea@cim.spin.com.mx

BACKGROUND: A significant association of cola beverage consumption and increased risk of bone fractures has been recently reported. The present study was carried out to examine the relationship of cola soft drink intake and bone mineral density in ovariectomized rats. METHODS: Study 1. Four groups of 10 female Sprague-Dawley rats were studied. Animals from groups II, III, and IV were bilaterally ovariectomized. Animals from groups I and II received tap water for drinking, while animals from groups III and IV each drank a different commercial brand of cola soft drink. After 2 months on these diets, the following were measured: solid diet and liquid consumption; bone mineral density; calcium in bone ashes; femoral cortex width; calcium; phosphate; albumin; creatinine; alkaline phosphatase; 25-OH hydroxyvitamin D, and PTH. RESULTS: Study 2. Two groups of seven ovariectomized rats were compared. Group A animals received the same management as the group III animals from study 1 (cola soft drink and rat chow ad libitum), while rats from group B received tap water for drinking and pair-feeding. After 2 months plasmatic ionized calcium, phosphate, creatinine, albumin, calcium in femoral ashes, and femoral cortex width were measured.Study 1. Rats consuming cola beverages (groups III and IV) had a threefold higher liquid intake than rats consuming water (groups I and II). Daily solid food intake of rats consuming cola soft drinks was one-half that of rats consuming water. Rats consuming soft drinks developed hypocalcemia and their femoral mineral density measured by DEXA was significantly lower than control animals as follows: group I, 0.20 +/- 0.02; group II, 0.18 +/- 0.01; group III, 0.16 +/- 0.01, and group IV, 0.16 +/- 0.01 g/cm(2). Study 2. To rule out the possibility that these calcium and bone mineral disorders were caused by decreased solid food intake, a pair-fed group was studied. Despite a lower body weight, pair-fed animals consuming tap water did not develop bone mineral reduction or hypocalcemia. CONCLUSIONS: These data suggest that heavy intake of cola soft drinks has the potential of reducing femoral mineral density.

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#20
Osteoporosis as a lifestyle-related disease

[Article in Japanese]Nippon Rinsho 2003 Feb;61(2):305-13

Hata M, Miyao M, Mizuno Y.

Division of Endocrinology and Metabolism, Kanto Central Hospital.

Although genetic factors determine the limits of peak bone mass, environmental factors can modify the outcome. Relation between lifestyle and osteoporosis is discussed, in terms of nutrition and habits. Significant link between calcium intake and bone mass has been reported. Although recommended daily allowance of calcium is 600 mg/day for adults, 850 mg/day or more shall be recommended later in life. Vitamin D insufficiency may lead to secondary hyperparathyroidism in the elderly, the condition that facilitates bone loss. Other nutrients that affect bone turnover include vitamin K, vitamin C, protein, potassium, salt, magnesium and phosphorus. Too much intake of caffeine or alcohol, as well as smoking is a risk factor of osteoporosis. Mechanical loading on the skeleton increases bone mass, therefore weight-bearing activity is recommended to gain or preserve bone mass.

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#21

Low protein intake: the impact on calcium and bone homeostasis in humans.

Kerstetter JE, O’Brien KO, Insogna KL.J Nutr 2003 Mar;133(3):855S-61S

School of Allied Health, University of Connecticut, Storrs, CT 06269-2101, Johns Hopkins Bloomberg School of Public Health, Center for Human Nutrition, Baltimore, MD 21218 and. Yale University School of Internal Medicine, New Haven, CT 06520-8020.

Increasing dietary protein results in an increase in urinary calcium. Despite over 80 y of research, the source of the additional urinary calcium remains unclear. Because most calcium balance studies found little effect of dietary protein on intestinal calcium absorption, it was assumed that the skeleton was the source of the calcium. The hypothesis was that the high endogenous acid load generated by a protein-rich diet would increase bone resorption and skeletal fracture. However, there are no definitive nutrition intervention studies that show a detrimental effect of a high protein diet on the skeleton and the hypothesis remains unproven. Recent studies from our laboratory demonstrate that dietary protein affects intestinal calcium absorption. We conducted a series of short-term nutrition intervention trials in healthy adults where dietary protein was adjusted to either low, medium or high. The highest protein diet resulted in hypercalciuria with no change in serum parathyroid hormone. Surprisingly, within 4 d, the low protein diet induced secondary hyperparathyroidism that persisted for 2 wk. The secondary hyperparathyroidism induced by the low protein diet was attributed to a reduction in intestinal calcium absorption (as assessed by dual stable calcium isotopes). The long-term consequences of these low protein-induced changes in calcium metabolism are not known, but they could be detrimental to skeletal health. Several recent epidemiological studies demonstrate reduced bone density and increased rates of bone loss in individuals habitually consuming low protein diets. Therefore, studies are needed to determine whether low protein intakes directly affect rates of bone resorption, bone formation or both.
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#22

Authors;Ilich JZ. Brownbill RA. Tamborini L.

Institution; University of Connecticut, School of Allied Health, Storrs, Connecticut 06269, USA.

Title; Bone and nutrition in elderly women: protein, energy, and calcium as main determinants of bone mineral density.[erratum appears in Eur J Clin Nutr. 2003 Jul;57(7):880].

Source; European Journal of Clinical Nutrition. 57(4):554-65, 2003 Apr.

Abstract

OBJECTIVE: Nutrition is an important factor in the prevention and treatment of osteoporosis. Our goal was to examine the relationship between various nutrients and bone mass of several skeletal sites in elderly women, taking into account possible confounding variables. DESIGN/METHODS: A cross-sectional study in 136 healthy Caucasian, postmenopausal women, free of medications known to affect bone was carried out. Bone mineral density (BMD) and body composition (lean and fat tissue) were measured by dual X-ray absorptiometry using specialized software for different skeletal sites. Parathyroid hormone (PTH) and vitamin D, 25(OH)D, as possible confounders, were determined in serum samples. Dietary intake, including all supplements, was assessed by 3-day dietary record and analyzed using Food Processor. Past physical activity and present walking were examined as well and accounted for as potential confounders. Simple and multiple regression models were created to assess the relationships between nutrients and BMD. To examine the co-linear variables and their possible independent association with bone, subgroup analyses were performed. RESULTS: : Showed independent influence of calcium, energy, and protein, examined separately and in multiple regression models on BMD of several skeletal sites. Magnesium, zinc and vitamin C were significantly related to BMD of several skeletal sites in multiple regression models (controlled for age, fat and lean tissue, physical activity and energy intake), each contributing more than 1% of variance. Serum PTH and 25(OH)D did not show significant association with bone mass. CONCLUSIONS: Despite the cross-sectional nature of our study we were able to show a significant relationship between BMD and several critical nutrients: energy, protein, calcium, magnesium , zinc and vitamin C. The exact involvement of these nutrients and their clinical significance in bone health need to be further elucidated in humans and conclusions about the effects of a single nutrient on bone mass must be given cautiously, taking into account its interaction and co-linearity with others. Understanding relationships among nutrients, not just limited to calcium and vitamin D, but others that have not been investigated to such extent, is an important step toward identifying preventive measures for bone loss and prevention of osteoporosis.

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#23

Vitamin D supplementation and bone mineral density in early postmenopausal women. Cooper L, Clifton-Bligh PB, Nery ML, Figtree G, Twigg S, Hibbert E, Robinson BG.Am J Clin Nutr 2003 May;77(5):1324-9

Department of Diabetes, Endocrinology and Metabolic Medicine, Northern Metabolic Bone Centre (LC, PBC-B, MLN, GF, and EH), and the Kolling Institute of Medical Research (ST and BGR), Royal North Shore Hospital, St Leonards, Australia.

BACKGROUND: Increased vitamin D intake may preserve or increase bone mineral density (BMD) in older persons. OBJECTIVE: A 2-y double-blind study was undertaken to determine whether weekly administration of 10 000 units of vitamin D(2) maintained or increased BMD in younger postmenopausal women more efficiently than did calcium supplements alone. DESIGN: One hundred eighty-seven women who were >/= 1 y postmenopausal were randomly assigned to take either 1000 mg Ca/d after the evening meal or 1000 mg Ca/d plus 10 000 U vitamin D(2)/wk in a double-blind, placebo-controlled format. The BMD of the proximal forearm, lumbar spine, femoral neck, Ward’s triangle, and femoral trochanter was measured at 6-mo intervals by osteodensitometry. RESULTS: During the 2-y period, there was no significant difference in the change in BMD at any site between the subjects taking calcium supplements and those taking calcium plus vitamin D(2). Both groups significantly (P < 0.005) gained BMD in Ward’s triangle and the femoral trochanter but significantly (P < 0.005) lost bone in the proximal radius. There was no significant change in the lumbar spine or femoral neck BMD. CONCLUSION: In younger postmenopausal women ( age: 56 y) whose average baseline serum 25-hydroxyvitamin D concentration was well within the normal range, the addition of 10 000 U vitamin D(2)/wk to calcium supplementation at 1000 mg/d did not confer benefits on BMD beyond those achieved with calcium supplementation alone. —————————————————–

#24

Bone mineral density in adolescent and young adult women on injectable or oral contraception.: Curr Opin Obstet Gynecol. 2003 Oct;15(5):353-357.

Cromer BA.

SUMMARY: PURPOSE OF REVIEW This report critically reviews recent original research articles that pertain to bone mineral density in young adult women utilizing injectable depot medroxyprogesterone acetate or oral contraceptives.RECENT FINDINGS Some evidence indicates that depot medroxyprogesterone acetate and ultra-low dose oral contraceptives (containing 20 microg ethinyl estradiol) may interfere with the large increases normally observed in adolescence; however, the same degree of bone loss (or lack of bone gain) associated with these drugs is not so impressive in young adult women who would typically be experiencing small changes in bone mass. Data obtained from young adult women show that low dose (30-40 microg ethinyl estradiol) oral contraceptives seem to be more protective of bone than ultra-low dose oral contraceptives. The few extant data suggest that there may be substantial increases in bone mass after discontinuation of depot medroxyprogesterone acetate; no information is available regarding the response of bone after discontinuation of oral contraceptives. As the clinical risk for fracture is usually several decades later, several exogenous factors such as diet and exercise may exert overriding influences on later bone health. Moreover, without contraception, the clinical outcome may be unwanted pregnancy and its potential impact on bone health.SUMMARY Recent findings suggest that depot medroxyprogesterone acetate and ultra-low dose oral contraceptives may interfere with achieving optimal peak bone mass in very young women; however, there may be substantial recovery after cessation of these methods and overriding long-term influences on bone health imposed by a myriad of lifestyle factors.

————————————————– Calcium supplementation provides an extended window of opportunity for bone mass accretion after menarche.

Rozen GS, Rennert G, Dodiuk-Gad RP, Rennert HS, Ish-Shalom N, Diab G, Raz B, Ish-Shalom S.Am J Clin Nutr. 2003 Nov;78(5):993-8.

Department of Clinical Nutrition, Rambam Medical Center Haifa, Haifa, Israel. rgeila@rambam.helath.gov.il

BACKGROUND: High calcium intakes during adolescence may increase bone acquisition. The magnitude of the effect of dietary calcium supplementation and the timing of its administration to achieve significant effects on bone health are still incompletely defined. OBJECTIVE: The objective of this study was to assess the effect of calcium supplementation on bone mass accretion in postmenarcheal adolescent girls with low calcium intakes. DESIGN: A double-blind, placebo-controlled calcium supplementation study was implemented. One hundred girls with a mean (+/- SD) age of 14 +/- 0.5 y with habitual calcium intakes < 800 mg/d completed a 12-mo protocol. The treatment group received a daily supplement containing 1000 mg elemental calcium. Bone mineral density (BMD) and bone mineral content (BMC) of the total body, lumbar spine, and femoral neck were determined at inclusion, 6 mo, and 12 mo. Also measured were serum concentrations of biochemical markers of bone turnover (osteocalcin and deoxypyridinoline), parathyroid hormone, and vitamin D. RESULTS: The calcium-supplemented group had greater accretion of total-body BMD and lumbar spine BMD but not BMC than did the control group. Calcium supplementation appeared selectively beneficial for girls who were 2 y postmenarcheal. Calcium supplementation significantly decreased bone turnover and decreased serum parathyroid hormone concentrations. CONCLUSION: Calcium supplementation of postmenarcheal girls with low calcium intakes enhances bone mineral acquisition, especially in girls > 2 y past the onset of menarche.

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