Effects of excess calcium as a different form on mineral metabolism in rats

Abstract

Excess calcium is known to affect the metabolism of other minerals. Calcium carbonate is the main source of calcium used in previous experiments that investigated excess calcium. Thus, it remains to be clarified whether other forms of calcium also have the same adverse effects. The effects of a high‐calcium carbonate diet or a high‐calcium citrate diet on mineral concentration in several tissues of rats were examined. Male rats aged 5 weeks were fed one of the experimental diets for 4 weeks. The control diet contained calcium as calcium carbonate at the requirement level. High‐calcium diets contained calcium carbonate or calcium citrate at a level of fivefold greater than the requirement level. In rats fed the high‐calcium diets, a similar decrease in phosphorus (in the plasma) and iron (in the testis, liver and femur) was observed. Hepatic copper increased in rats fed the high‐calcium diets, whereas renal copper decreased. Therefore, excess calcium affects these mineral metabolisms regardless of its form. In contrast, the high‐calcium carbonate diet increased femoral zinc and decreased femoral magnesium, but the high‐calcium citrate diet did not affect these minerals in the femur, which suggests that the effect of excess calcium on minerals partly depends on its form.

Effects of dietary calcium levels on growth and tissue mineralization in Japanese seabass,Lateolabrax japonicus

“…); and Fe and Mg in rat bones (Takasugi et al . ). These reports indicated that changing dietary Ca level affected the availability of other minerals in fish and terrestrial animals, probably by competitive inhibition of these cations during intestinal absorption (Roy & Lall ).…”

“…Simultaneous administration of dietary Ca induced a significant decrease in other bivalent minerals, such as Zn, Fe and Mn in vertebrae and Mg and Mn contents in scales. Increasing levels of dietary Ca also decreased Mg in the scales and vertebrae of Atlantic salmon (Vielma & Lall 1998); Fe, Zn and Mn in the vertebrae of scorpion fish (Hossain & Furuichi 2000a); Zn and Mg in the vertebrae and scales, respectively, of juvenile grouper (Ye et al 2006); and Fe and Mg in rat bones (Takasugi et al 2005). These reports indicated that changing dietary Ca level affected the availability of other minerals in fish and terrestrial animals, probably by competitive inhibition of these cations during intestinal absorption (Roy & Lall 2003).…”

Magnesium Supplementation did not Affect the Increasing Bone Zinc Concentration in Rats Given Excess Calcium as Carbonate

“…Our previous report showed that bone Zn concentration was increased and bone Mg concentration was decreased by excess Ca as carbonate but that these changes were not observed in the rats given the same amount of Ca as citrate [9]. Therefore, we hypothesized that the secondary Mg insufficiency increased bone Zn concentration in rats given excess Ca.…”

“…As mentioned above, bone Zn concentration was increased by the excess Ca as carbonate but not by the excess Ca as citrate [9]. Thus, carbonate itself possibly increases bone Zn concentration.…”

“…Planells et al [8] reported that Mg deficiency increased bone Zn concentration in rats. Additionally, Takasugi et al [9] reported that excess Ca as carbonate increased Zn concentration and decreased Mg concentration in bone but that excess Ca as citrate did not affect Mg and Zn concentrations in bone. Therefore, the secondary Mg insufficiency possibly increases bone Zn concentration in rats given excess Ca as carbonate.…”