A human body weighing 70kg contains approximately 20 to 28g of magnesium and in general a human body contains approximately 0.5g of magnesium per kilogram of fat free body tissue. A large fraction of total body magnesium is present in bone and next in muscle, liver and heart. Each of the organs (muscle, liver and heart) contains about the same amount of magnesium. In the body, magnesium plays a key role as an essential ion in many foundamental enzymatic reaction and in intermediary metabolism. Also, the importance of magnesium in bone formation and neuromuscular transmission is well established. In 1978, Karppanen, et al. have claimed that the death rate from ischemic heart disease correlates with the dietary ratio of calcium and magnesium. This review, describe the magnesium intake and its balance in Japanese, and the effect of dietary magnesium on high intake of phosphorus in rats. 1) Magnesium intake of Japanese: Magnesium intake varies greatly because its widely variable content in different foods. In Japan the average range of magnesium intake for healthy adult is 200-300mg/day (Table 3) and that in child, range from 120-130mg/day. 2) Magnesium balance of Japanese: Balance study with adult (Table 4) and child (Table 5) indicated that the increasing dietary magnesium level was not affected strongly by the magnesium balance. 3) Effect of dietary magnesium level on high phosphorus intake: The use of phosphate as food additives has become so widespread that phosphorus content of ordinary daily diets may be inceased. High phosphorus diet greatly increased the concentration of calcium in rat kidney but magnesium addition to diet induced the reduction of calcium load in the kidney (Table 8).
The eating behavior such as the habit of chewing food and drinking water during meals and the physical activities were observed in subjects who were overweight and standard weight. The results obtained were as follows. 1) The overweight subjects were found to eat their meals very rapidly as they chewed less number of times and there was the negative correlation between the obesity index and the time spent in eating the meal. 2) The overweight subjects drank significantly more water during meals than the subjects whose weight was within the standard range. 3) The total energy intake in the standard weight subjects was positively correlated with the number of steps they walked on a day, but this correlation was not observed in the overweight subjects. This suggested that the energy regulating mechanism in the latter was not sufficiently operating. 4) The increase of energy intake in the overweight subjects was shown to be strongly affected by their eating behavior.