The Effect of Some Dietary Additives on Calcium and Strontium Absorption in Suckling and Lactating Rats

Summary The effect of calcium, phosphate and alginate additives to the diet on calcium-47 and strontium-85 absorption from the gut has been investigated in suckling and lactating rats. Suckling rats aged 5-7 days were artificially fed on cow's milk (8 hours a day during a period of 10 days) containing tracer amounts of calcium-47 and strontium-85 to which various amounts of calcium, phosphate and alginate were added. Variation in the calcium by seven-fold and in the phosphate by five-fold caused only minor changes in the absorption of radiostrontium from the gut and no changes in the percentage calcium-47 absorption. The results indicate that the total absorption of calcium was independent of the phosphate level and proportional to the calcium concentration in the milk. The addition of alginate to milk caused a two-fold reduction in radiostrontium retention by suckling rats without affecting calcium absorption from the intestine. The increased strontium absorption normally found in lactating rats was prevented by supplementing the maternal diet with calcium, phosphate and alginate but without affecting the increased calcium absorption.