Magnesium Deficiency Increases Resorption and Osteoclasts While Decreasing Bone Formation and Osteoblasts

Abstract

Magnesium deficiency-induced osteoporosis in the rat: uncoupling of bone formation and bone resorption.

Magnesium (Mg) intake has been linked to bone mass and/or rate of bone loss in humans. Experimental Mg deficiency in animal models has resulted in impaired bone growth, osteopenia, and increased skeletal fragility. In order to assess changes in bone and mineral homeostasis that may be responsible, we induced dietary Mg deficiency in adult Simonsen albino rats for 16 weeks. Rats were fed either a low Mg diet (0.002 percent) or a normal control Mg diet (0.063 percent). Blood was obtained at baseline, 4 weeks, 8 weeks, 12 weeks and 16 weeks in both groups for serum Mg, calcium, PTH, and 1.25(OH)2-vitamin D determinations. Femora were harvested at 4 weeks and 16 weeks for mineral analysis and histomorphometry. Serum Mg fell in the Mg depleted group to 0.6 mg/dl (mean) by 16 weeks (controls = 2.0 mg/dl). The serum calcium (Ca) concentration was higher in the Mg depleted animals at 16 weeks, 10.8 mg/dl (controls = 8.9 mg/dl). Serum PTH concentration fell progressively in the Mg deficient rats to 30 pg/ml by week 16 (control = 96 pg/ml). Serum concentration of 1.25(OH)2-vitamin D also fell progressively in the Mg deficient animals by 16 weeks to 14 pg/ml (control = 30 pg/ml). While the percent ash weights of Ca and phosphorus in the femur were not different at any time point, the percent ash weight of Mg progressively fell to 0.54 percent vs control (0.74 percent) by 16 weeks. The percent ash weight of potassium also fell progressively in the Mg deficient group to approximately 30 percent of control by 16 weeks. Histomorphometric analyses showed a significant drop in trabecular bone volume in Mg deficient animals by 16 weeks (percent BV/TV = 13.2 percent vs 17.3 percent in controls). Evaluation of the endosteal bone surface features showed significantly greater bone resorption in the Mg depleted group as reflected in increased number of tartrate-resistant positive osteoclasts/mm bone surface (7.8 vs 4.0 in controls) and an elevated percent of bone surface occupied by osteoclasts (percent OcS/BS = 12.2 percent vs 6.7 percent in controls. This increased resorption occurred in the presence of an inappropriate lowered bone forming surface relative to controls; a decreased number of osteoblasts per mm bone surface (0.23 vs 0.94 in control) and a decrease in percent trabecular surface lined by osteoid (percent OS/BS = 0.41 vs 2.27 percent in controls) were also noted. Our findings demonstrate a Mg-deficiency induced uncoupling of bone formation and bone resorption resulting in a loss of bone mass. While the fall in PTH and/or 1.25(OH)2-D may explain a decrease in osteoblast activity, the mechanism for increased osteoclast activity is unclear. These data suggest that Mg deficiency may be a risk factor for osteoporosis.

Rude RK, Kirchen ME, Gruber HE, Meyer MH…
Magnes Res Dec 1999
PMID: 10612083

Magnesium Reduces Bone Formation and Resorption in Young Men

Abstract

Daily oral magnesium supplementation suppresses bone turnover in young adult males.

This study examined the effects of daily oral magnesium (Mg) supplementation on bone turnover in 12 young (27-36 yr old) healthy men. Twelve healthy men of matching age, height, and weight were recruited as the control group. The study group received orally 15 mmol Mg (Magnosolv powder, Asta Medica) daily in the early afternoon with 2-h fasting before and after Mg intake. Fasting blood and second void urine samples were collected in the early morning on days 0, 1, 5, 10, 20, and 30, respectively. Total and ionized Mg2+ and calcium (Ca2+), and intact PTH (iPTH) levels were determined in blood samples. Serum biochemical markers of bone formation (i.e. C-terminus of type I procollagen peptide and osteocalcin) and resorption (i.e. type I collagen telopeptide) and urinary Mg level adjusted for creatinine were measured. In these young males, 30 consecutive days of oral Mg supplementation had no significant effect on total circulating Mg level, but caused a significant reduction in the serum ionized Mg+ level after 5 days of intake. The Mg supplementation also significantly reduced the serum iPTH level, which did not appear to be related to changes in serum Ca2+ because the Mg intake had no significant effect on serum levels of either total or ionized Ca2+. There was a strong positive correlation between serum iPTH and ionized Mg2+ (r = 0.699; P < 0.001), supporting the contention that decreased serum iPTH may be associated with the reduction in serum ionized Mg2+. Mg supplementation also reduced levels of both serum bone formation and resorption biochemical markers after 1-5 days, consistent with the premise that Mg supplementation may have a suppressive effect on bone turnover rate. Covariance analyses revealed that serum bone formation markers correlated negatively with ionized Mg2+ (r = -0.274 for type I procollagen peptide and -0.315 for osteocalcin), but not with iPTH or ionized Ca2+. Thus, the suppressive effect on bone formation may be mediated by the reduction in serum ionized Mg2+ level (and not iPTH or ionized Ca2+). In summary, this study has demonstrated for the first time that oral Mg supplementation in normal young adults caused reductions in serum levels of iPTH, ionized Mg2+, and biochemical markers of bone turnover. In conclusion, oral Mg supplementation may suppress bone turnover in young adults. Because increased bone turnover has been implicated as a significant etiological factor for bone loss, these findings raise the interesting possibility that oral Mg supplementation may have beneficial effects in reducing bone loss associated with high bone turnover, such as age-related osteoporosis.

Dimai HP, Porta S, Wirnsberger G, Lindschinger M…
J. Clin. Endocrinol. Metab. Aug 1998
PMID: 9709941

Magnesium Suppresses Bone Resorption Rats Fed a High-Phosphorus Diet

Abstract

Dietary magnesium supplementation suppresses bone resorption via inhibition of parathyroid hormone secretion in rats fed a high-phosphorus diet.

This study examined the effects of dietary magnesium (Mg) supplementation on bone turnover and serum parathyroid hormone (PTH) levels in rats fed a high-phosphorus (P) diet. Male rats were randomized by weight into three groups, and fed a control diet (control), a high-P diet (HP) or a high-P and high-Mg diet (HPHMg) for 14 days. Serum osteocalcin levels were significantly higher in the HP and HPHMg groups than in the control group. Serum CTx levels were significantly higher in the HP and HPHMg groups than in the control group, while the levels in the HPHMg group were significantly lower than in the HP group. Serum PTH levels were significantly higher in the HP group than in the control and HPHMg groups. Dietary Mg supplementation had a significant influence on serum PTH levels in the HP and HPHMg groups. These results suggest that dietary Mg supplementation suppresses the high bone resorption induced by a high-P diet via inhibition of PTH secretion. Moreover, our results suggest that dietary Mg supplementation may be beneficial for the prevention of bone loss with high-P diet administration.

Matsuzaki H, Fuchigami M, Miwa M
Magnes Res Sep 2010
PMID: 20810356 | Free Full Text

Magnesium Water No Benefit in Postmenopausal Women

Abstract

A double-blind, placebo-controlled study of the short term effects of a spring water supplemented with magnesium bicarbonate on acid/base balance, bone metabolism and cardiovascular risk factors in postmenopausal women.

A number of health benefits including improvements in acid/base balance, bone metabolism, and cardiovascular risk factors have been attributed to the intake of magnesium rich alkaline mineral water. This study was designed to investigate the effects of the regular consumption of magnesium bicarbonate supplemented spring water on pH, biochemical parameters of bone metabolism, lipid profile and blood pressure in postmenopausal women. In this double-blind, placebo-controlled, parallel-group, study, 67 postmenopausal women were randomised to receive between 1500 mL and 1800 mL daily of magnesium bicarbonate supplemented spring water (650 mg/L bicarbonate, 120 mg/L magnesium, pH 8.3-8.5) (supplemented water group) or spring water without supplements (control water group) over 84 days. Over this period biomarkers of bone turnover (serum parathyroid hormone (PTH), 1,25-dihydroxyvitamin D, osteocalcin, urinary telopeptides and hydroxyproline), serum lipids (total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides), venous and urinary pH were measured together with measurements of standard biochemistry, haematology and urine examinations. Serum magnesium concentrations and urinary pH in subjects consuming the magnesium bicarbonate supplemented water increased significantly at Day 84 compared to subjects consuming the spring water control (magnesium – p = 0.03; pH – p = 0.018). The consumption of spring water led to a trend for an increase in parathyroid hormone (PTH) concentrations while the PTH concentrations remained stable with the intake of the supplemented spring water. However there were no significant effects of magnesium bicarbonate supplementation in changes to biomarkers of bone mineral metabolism (n-telopeptides, hydroxyproline, osteocalcin and 1,25-dihydroxyvitamin D) or serum lipids or blood pressure in postmenopausal women from Day 0 to Day 84.
Short term regular ingestion of magnesium bicarbonate supplemented water provides a source of orally available magnesium. Long term clinical studies are required to investigate any health benefits.

Day RO, Liauw W, Tozer LM, McElduff P…
BMC Res Notes 2010
PMID: 20579398 | Free Full Text

The acid/base theory is questionable and this was a low dose of Magnesium.

Review: Vitamin A Increases Fracture Risk at 2x Recommended Intake

Abstract

Vitamin A intake and osteoporosis: a clinical review.

If osteoporosis is linked with vitamin A (Vit A) A consumption, millions of people could be affected. A MEDLINE search was performed with keywords retinol, beta-carotene, and osteoporosis. Of 20 clinical studies, 3 were randomized controlled trials (RCTs), 14 were observational studies, and 3 were case reports. Most (8) observational studies were cross-sectional. Oral retinoyl palmitate (RP) in high doses induces fractures and radiographic osteoporosis in animals. Retinol intake from diet or supplements is negatively associated with lumbar, femoral neck, and trochanter bone mineral density (BMD). There is a graded increase in relative risk of hip fracture with increasing retinol intake, attributable primarily to retinol (either from diet or supplements) but not beta-carotene intake. Higher serum retinol levels are associated with higher risk of any fracture and with higher risk of hip fracture, whereas there is no evidence of harm associated with beta-carotene intake. The few RCTs involve serum markers of bone metabolism, not bone density or fracture outcomes. Observational studies are generally consistent in finding harm from either dietary or supplemental retinol intake on BMD and hip fracture risk. Total Vit A intake is more important than source in determining harm. Adverse effects may occur at a level of retinol intake that is only about twice the current recommendation for adult females.
It is not yet possible to set a specific level of retinol intake above which bone health is compromised. Pending further investigation, Vit A supplements should not be used with the express goal of improving bone health.

Crandall C
J Womens Health (Larchmt) Oct 2004
PMID: 15671709

The recommended dietary allowance (RDA) for Vitamin as preformed Vitamin A (Retinol Activity Equivalents) is 700 mcg (or 2,333 IU). This article suggests that twice that, or 4666 IU, increases fracture risk.

Vitamin A Not Associated with Bone Density or Fracture in 2016 Perimenopausal Danish Women

Abstract

No effect of vitamin A intake on bone mineral density and fracture risk in perimenopausal women.

In recent studies from Sweden and the United States, a high vitamin A intake has been associated with low bone mineral density (BMD) and increased fracture risk. In Sweden and the United States, food items such as milk and breakfast cereals are fortified with vitamin A, whereas in Denmark there is no mandatory fortification with vitamin A. In the present study, we investigated relations between vitamin A intake and BMD and fracture risk in a Danish population consuming mostly unfortified food items. Within a population-based cohort study in 2,016 perimenopausal women, associations between BMD and vitamin A intake were assessed at baseline and after 5-year follow-up. Moreover, associations between baseline vitamin A intake and 5-year changes in BMD were studied. Finally, fracture risk was assessed in relation to vitamin A intake. In our cohort, dietary retinol intake (0.53 mg/day) was lower than the intake reported in recent studies form Sweden (0.78 mg/day) and the United States (1.66 mg/day). Cross-sectional and longitudinal analyses showed no associations between intake of vitamin A and BMD of the femoral neck or lumbar spine. Neither did BMD differ between those 5% who had the highest, and those 5% who had the lowest, vitamin A intake. During the 5-year study period, 163 subjects sustained a fracture (cases). Compared to 978 controls, logistic regression analyses revealed no difference in vitamin A intake. Thus, in a Danish population, average vitamin A intake is lower than in Sweden and the United States and not associated with detrimental effects on bone.

Rejnmark L, Vestergaard P, Charles P, Hermann AP…
Osteoporos Int Nov 2004
PMID: 15034644

Korean Black Raspberry Enhances Osteoblast Function In Vitro

Abstract

Rubus coreanus Miq. extract promotes osteoblast differentiation and inhibits bone-resorbing mediators in MC3T3-E1 cells.

To prevent bone loss that occurs with increasing age, certain nutritional and pharmacological factors are needed. In the present study, the ethanol extract from the fruit of Rubus coreanus Miq. (RCE) was investigated for its effect on the function of osteoblastic MC3T3-E1 cells. RCE (10approximately50 microg/ml) caused a significant elevation in cell viability, alkaline phosphatase (ALP) activity, collagen content, and osteocalcin secretion in the cells. The effect of RCE (50 microg/ml) in increasing cell viability, ALP activity, and collagen content was prevented by the presence of 10(-6) M cycloheximide and 10(-6) M tamoxifen, suggesting that RCE’s effect results from a newly synthesized protein component and might be partly involved in estrogen action. We then examined the effect of RCE on the H(2)O(2)-induced apoptosis and production of local factors in osteoblasts. Treatment with RCE (10approximately50 microg/ml) decreased the 0.2 mM H(2)O(2)-induced apoptosis and production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and nitric oxide (NO) in osteoblasts. Our data indicate that the enhancement of osteoblast function by Rubus coreanus Miq. may result in the prevention of osteoporosis and inflammatory bone diseases.

Lee KH, Choi EM
Am. J. Chin. Med. 2006
PMID: 16883635

Korean Black Raspberry Increases Osteoblasts and Apoptosis of Osteoclasts in Ovariectomized Rats

Abstract

Bone-protecting effect of Rubus coreanus by dual regulation of osteoblasts and osteoclasts.

Bone loss occurs with increasing age and/or as a secondary occurrence to chronic metabolic disease. Certain nutritional and pharmacological, as well as nonpharmacologic interventions such as weight-bearing exercise and muscle strengthening help prevent bone loss. We examined the effect of the methanol extract from the fruit of Rubus coreanus (RCM) on postmenopausal osteoporosis.
Ovariectomized rats were assigned to sham (negative control), vehicle control, positive control, safflower seed 200 mg/kg, RCM 100 mg/kg (RCM 100), RCM 200 mg/kg (RCM 200), and RCM 400 mg/kg (RCM 400) groups for 10 weeks after the operation. Serum biochemistry, histochemistry, immunohistochemistry, and other related biomarkers of bone metabolism were investigated.
We observed that RCM could prevent bone loss by increasing the femur trabecular bone area in a dose-dependent manner in ovariectomized rats. The mineral composition of RCM contains many more valuable elements, especially potassium, magnesium, and vitamins D and B2, than safflower seed. The effect of RCM increased not only osteoblast differentiation but also osteoclast apoptosis. In addition, the extract of RCM contained in quercetin suggests that the extract of RCM resulted in improved aging-related bone loss through an antioxidant effect.
The present data provide the first direct in vivo evidence that RCM has a bone-protecting effect caused by estrogen deficiency, without undesirable side effects on the uterus and other solid organs. The beneficial effect of RCM may be mediated, at least in part, by dual regulation of the enhancement of osteoblast function and induction of osteoclast apoptosis.

Do SH, Lee JW, Jeong WI, Chung JY…
Menopause
PMID: 18709701

Sodium Associated with Higher Bone Density

Abstract

Dietary sodium and bone mineral density: results of a 16-year follow-up study.

It has been proposed that high dietary sodium intake, resulting in a sodium-mediated increase in renal calcium excretion, is a risk factor for osteoporosis. To evaluate the relationship between dietary sodium intake and bone mineral density (BMD), a prospective study of the Rancho Bernardo cohort was performed. A 24-hour diet recall was done for the period 1973 through 1975; follow-up bone mineral density of the ultradistal radius, midradius, total hip, and spine was measured between 1988 and 1991. Covariates were ascertained by self-report and examination at baseline. Multivariable analysis of the sodium-BMD association was performed using gender and menopause-specific linear regressions.
All subjects were white. At the bone evaluation, there were 258 women (average age 73.3 years) and 169 men (average age 72.4 years). In both men and women, higher levels of sodium intake were strongly associated with higher levels of calcium intake and total calories. Body mass index increased with sodium quartile in women, while a modest negative association was seen in men. In women, after age adjustment, positive associations between dietary sodium and bone density were found at the ultradistal radius (beta = 0.01, P = 0.03) and the total hip (beta = 0.019, P = 0.02). BMD increased by 0.01 to 0.02 g/cm2 per gram increase in sodium ingested. After adjustment for estrogen use, body mass, dietary calcium, alcohol, and total calories, these effects were no longer significant. Similar patterns were seen in pre- and postmenopausal women. In men, age and multivariate-adjusted BMD increased with higher sodium intake at the ultradistal radius only (beta = 0.013, P = 0.05). Stratification by gender-specific median calcium level did not significantly effect the results.
After control for confounders, a small, statistically significant protective effect of sodium was found at the ultradistal radius in men only. At other sites in women and men, no effect of sodium on BMD was apparent in the multivariable models. These results do not support a detrimental effect of dietary sodium on bone mineral density. Rather, the findings suggest that sodium intake, in the range measured, is not a major osteoporosis risk factor.

Greendale GA, Barrett-Connor E, Edelstein S, Ingles S…
J Am Geriatr Soc Oct 1994
PMID: 7930328

Review: Optimal Treatment may Include Both Anabolic and Antiresorptive Treatments

Abstract

Future directions in osteoporosis therapeutics.

Future directions in osteoporosis treatment will include development of medications with increasingly precise mechanistic targets, including the RANK-ligand pathway, cathepsin K inhibition, and Wnt signaling manipulation. More gains are likely with anabolics and newer antiresorptives that cause little or no suppression of formation. Optimal treatment of osteoporosis may require coordination of anabolic and antiresorptive treatment, following stimulation of bone formation with consolidation and long-term maintenance. Some well-established drugs may be useful in such regimens. We can also anticipate emphasis on cost containment using currently available drugs, especially as they become generic. Effective implementation and treatment continuity will be important themes.

Bone H
Endocrinol. Metab. Clin. North Am. Sep 2012
PMID: 22877435