镁在细胞内是第2个重要离子,其含量仅次于钾,总体镁约24克,正常血清镁浓度1.4～2.1mEq/L(1.7～2.3mg%). 正常人每天从饮食中摄入镁约300mg,大约1/3为胃肠道所吸收.主要从肾排出,每天大约有40毫克分子(3500mg)镁被滤过,其再吸收大部分在肾小管,滤过镁仅3%(约100mg)从尿中排泄,相当于每天从胃肠道吸收的镁.故若镁的摄取过少、胃肠道消化吸收不良或排出过多,均易造成缺镁. Magnesium in the cells is the second important ion, its content is second only to potassium, the total magnesium is about 24 grams, the normal serum magnesium concentration of 1.4 ~ 2.1mEq / L (1.7 ~ 2.3mg%) normal daily intake from the diet About 300 mg of magnesium, about one-third is absorbed by the gastrointestinal tract and is mainly excreted from the kidneys. Approximately 40 milligrams (3500 mg) of magnesium is filtered daily, reabsorbing most of it in the renal tubules and only 3% About 100mg) excreted from the urine, equivalent to the daily intake of magnesium from the gastrointestinal tract .If the magnesium intake is too small, gastrointestinal digestion and malabsorption or excretion are likely to cause magnesium deficiency.