The effect of moderately and severely restricted dietary magnesium intakes on bone composition and bone metabolism in the rat

Abstract

Forty 3-week-old male rats, Wistar strain, average weight 59 g, were randomized by weight into five groups of eight rats each. Three groups were fed ad libitum on a semi-purified diet containing (per kg) 400 (adequate), 200 (moderately Mg-restricted) or 20 (severely Mg-restricted) mg Mg for 3 weeks while two groups were pair-fed with the Mg-adequate diet in the same quantities as those consumed by the two Mg-restricted groups respectively. While weight gains and food conversion efficiency values for the Mg-restricted groups were similar to those of the corresponding pair-fed control groups, serum and kidney Mg, and femoral dry weight were reduced by 70, 7 and 9 % respectively in the severely Mg-restricted group and were unaffected in the moderately Mg-restricted group. Significant reductions were observed in urinary pyridinoline (Pyr) (by 44 and 34 %) and deoxypyridinoline (Dpyr) levels (by 40 and 33 %) (markers of bone resorption), serum osteocalcin levels (by 46 and 28 %) (marker of bone formation), femoral Mg levels (by 52 and 14 %) and osteocalcin mRNA levels (by 46 and 22 %) compared with the corresponding pair-fed controls, in the severely and moderately Mg-restricted groups respectively, and these reductions, except for those in urinary Pyr and Dpyr, were more marked in the severely Mg-restricted group. Femoral Ca and P concentrations were unaffected by dietary Mg restriction. These results show that not only severe but also moderate dietary restriction of Mg over 21 d results in qualitative changes in bone (i.e. reduced Mg concentration) as well as in aberrant bone turnover in young growing rats (i.e. severely depressed rates of bone formation and bone resorption), which may impair bone development and bone strength.

Structural Characterization and Biological Fluid Interaction of Sol−Gel-Derived Mg-Substituted Biphasic Calcium Phosphate Ceramics

“…On the contrary, (5) 4.10(3) 00Mg1100 0.0 1100 91.7(2) 9.42454(2) 6.88429(2) 1.11(4) 10.4412(5) 37.401 (3) 7.14(3) 05Mg1100 0.5 1100 87.3(3) 9.42456(2) 6.88434(2) 12.2(2) 10.4241(2) 37.3883 (9) 0.39(2) 0.11(2) 10Mg1100 1.0 1100 76.4(2) 9.42414(2) 6.88448 (2) 22.4(2) temperature dependence is observed for the anisotropy of the HAp crystallites morphology (Figure 1c), for the HAp and -TCP coherent domain sizes, and for HAp and -TCP average maximum strains (Table SI1 of (43)) is also invariant with the temperature of calcination. Upon heating, an important increase of the coherent domain sizes (from about 500 Å at 500°C to more than 2000 Å at 1100°C) for both HAp and -TCP phases and a clear decrease of the average maximum strains (from 2.0% at 500°C to 0.1% at 1100°C) for the HAp phase are observed.…”

The effect of magnesium supplementation on biochemical markers of bone metabolism or blood pressure in healthy young adult females

“…Usually bone formation, although coupled to resorption, is separated in time by approximately 6 ± 7 weeks (Eriksen et al, 1984), and therefore a reduction in both these processes within 5 d of beginning Mg supplementation seems unusual. While concomitant reductions in both osteoblastic and osteoclastic activity have been reported in rats due to Mg de®ciency (Jones et al, 1980;Creedon et al, 1998), there is no supporting evidence in the literature, either in humans or in experimental animals, of a concomitant reduction in the rates of bone formation and bone resorption due to supplementation with a nutritional level of Mg. Limitations of the study of Dimai et al (1998) included relatively low subject numbers and it was not of a randomised crossover design.…”

Acute effect of high-calcium milk with or without additional magnesium, or calcium phosphate on parathyroid hormone and biochemical markers of bone resorption

“…It has been known for many years that magnesium (Mg) deficiency leads to an increase in serum PTH, which promotes calcium (Ca) release from bone (Rude et al, 1976). More recently Mg deficiency for just 3 weeks in young, growing rats has been shown to lead to decreased bone turnover that could impair bone growth and development (Creedon et al, 1999). Correcting deficiencies in Mg intake is therefore likely to be important for bone health.…”