Growth Check and Magnesium Imbalance on Young Rats By Over Intakes Of Calcium

Osteoporosis in women, that is age-associated bone loss 1) and calcium intake (537 mg/day in average of Japanese) by national nutritional survey less than the current RDA for calcium of 600 mg/day are focused in Japan 2). Therefore recently a significant increase in supply of calcium supplements and the introduction of many kinds of calcium- fortified foods is widely resulted. To Prevent bone loss, public or research attention for increasing of calcium intake was reported 3–5). Effects of low- or high- calcium intakes on zinc balance in humans were also reported 6,7). On the other hand, protein and lipid intakes are increasing with westernized food habits of Japanese 2). In our previous, it was studied that high protein intake with lower calcium intake induced a turn for the worse of osteoporosis 8). Some reports were shown as following that studies using isolated protein sources had shown an increase in urinary calcium excretion and a negative calcium balance in subjects fed a high-protein diet compared with a moderate- protein diet 9), and when phosphate was allowed to rise naturally as the protein intake was increased, no hypercalciuria nor fall in calcium balance was observed 10). Effect of high sodium intake on calcium retention in postmenopausal women was also demonstrated 11,12). But high intake of calcium induced low zinc absorption 13–17). In this report, lesions by over intake of calcium on health and mineral status in rats are studied.