Comparative study of the intestinal absorption of three salts of calcium in young and elderly women.

A daily ingestion of 1000 to 1500 mg elemental calcium associated with vitamin D supplement is presently considered to be the adequate and least expensive therapy for senile osteoporosis. There exists only scarce data about calcium absorption with available calcium salts in elderly patients. We have compared the digestive absorption of calcium (Ca) citrate in soluble and solid form and calcium gluconolactate-carbonate in 15 young and 20 elderly, healthy women using the oral calcium loading test. The subjects were divided into two groups. In the first group, the absorption of solid Ca citrate (1000 mg Ca element) was compared to the absorption of Ca gluconolactate-carbonate (1000 mg Ca element) both in young (n = 7) and elderly women (n = 10). In the second group, the absorption of soluble Ca citrate (1000 mg Ca element) was compared to the absorption of Ca gluconolactate-carbonate (1000 mg Ca element) in young (n = 8) and elderly (n = 10) women. In the preload phase, basal calciuria was increased in elderly women (p < 0.01) although basal calcemia was similar in young and elderly women. After oral administration of the calcium salts, an increase in plasma Ca was observed in both groups which was greater for soluble Ca citrate and Ca gluconolactate than for solid Ca citrate. In young women, the increase in plasma calcium was significantly higher with soluble Ca citrate compared to Ca gluconolactate (p < 0.05). In elderly women, the postload calciuria was significantly higher for soluble Ca citrate (p < 0.05) and Ca gluconolactate (p < 0.05) compared to solid Ca citrate. A similar pattern was observed in young women, although it was not significant. In conclusion, an oral load of 1000 mg soluble Ca citrate and Ca gluconolactate-carbonate induces significant biochemical changes suggesting a better digestive absorption compared to Ca citrate in solid form, both in young and elderly women. We did not observe different response, between young and old patients.