Dietary Magnesium Supplementation Affects Bone Metabolism and Dynamic Strength of Bone in Ovariectomized Rats

Abstract

We evaluated the effect of magnesium supplementation on apparent calcium absorption, bone metabolism and dynamic bone strength in ovariectomized (OVX) rats as a model of postmenopausal women. Two groups of OVX rats were fed a 0.05% Mg diet or a 0.15% Mg diet, and one group of sham-operated rats was fed the 0.05% Mg diet for 42 d. We collected feces and urine of all rats for 3-d periods starting from d 3, 10, 17, 24, 31 and 38 of the feeding experiment for calcium and magnesium balance studies. Urine was collected for 24 h from d 41 of the feeding experiment for measuring deoxypyridinoline. After the 42 d, the rats were killed, serum prepared and femora excised. The apparent calcium absorption in the OVX rats fed 0.15% Mg was significantly lower than both other groups. Additionally, the urinary excretion of deoxypyridinoline (a bone resorption marker) and the serum parathyroid hormone level of the OVX rats fed the 0.15% Mg diet were significantly lower than in the OVX rats fed 0.05% Mg. Serum osteocalcin (a bone formation marker) in the OVX rats fed the 0.15% Mg diet was significantly higher than in the OVX rats fed 0.05% Mg. The breaking force and breaking energy of the femur in the OVX rats fed the 0.15% Mg diet were significantly higher than in the OVX rats fed the 0.05% Mg diet. These results indicate that magnesium supplementation reduces apparent calcium absorption, but promotes bone formation and prevents bone resorption in OVX rats. Moreover, our results indicate magnesium supplementation increases the dynamic strength of bone.

A Case of Magnesium Deficiency Associated with Insufficient Parathyroid Hormone Action and Severe Osteoporosis

“…In addition, previous reports have shown that bone quality deteriorates under a low Mg condition [14,15], and that subjects at low serum Mg levels are at risk for bone fractures [12]. It has been reported that dietary Mg supplementation affected bone metabolism and dynamic strength of bone in ovariectomized rats [16]. Family members affected with primary hypomagnesemia due to renal Mg wasting inherited in an autosomal dominant manner have been reported to demonstrate significant reductions in serum and lymphocyte Mg concentrations as well as decreased BMD values at the lumbar spine and proximal femur [17].…”

“…In addition, Mg deficiency could inhibit the synthesis of 1,25-dihydroxy vitamin D (1,25(OH) 2 D) [9][10][11] as well as its action on bone [11]. Accumulating data have shown that a long-term Mg deficiency and resulting hypomagnesemia could cause osteoporosis and bone fractures through these dysfunctions of PTH and vitamin D action [12,[13][14][15][16][17][18][19]. However, other studies have shown no relationship between Mg deficiency and osteoporosis [20][21][22], and it still seems to be controversial whether or not Mg deficiency could cause osteoporosis.…”

Effect of dietary magnesium, calcium, phosphorus, and limestone grain size on productive performance and eggshell quality of hens

“…Toba et al (1999) reported that when doi: 10.17221/3/2016-CJAS growing male rats were fed three times more Mg compared to the control group, an increase in bone-breaking energy was observed. Toba et al (2000) also reported that Mg supplementation in ovariectomized rats promoted bone formation by activating osteoclasts. High Mg supplementation may cause laxative problems.…”

Nanostructured magnesium has fewer detrimental effects on osteoblast function

“…Similarly, Toba et al showed that magnesium supplementation promotes bone formation (increases in osteocalcin) and prevents bone resorption (decreases in deoxypyridinoline and parathyroid hormone). 13 They also found a reduction in calcium adsorption, which supports the decrease in bone resorption since lower levels of serum calcium stimulate the release of parathyroid hormone. 13 Given that magnesium is a mineral essential for bone growth, it can be expected that as a biomaterial it would support bone growth.…”