IMPORTANCE OF LACTOSE IN YOGURT FOR MINERAL UTILIZATION

Mineral utilization was assessed in mature female rats fed yogurt-based diets or casein-based diets that contained quantities of sucrose, lactose, or lactose's component sugars (glucose, galactose) equiv¬alent to the amount of lactose found in yogurt and one of two levels of calcium (4 or 8 mg of Ca/g of diet). Ingestion of the high level of calcium depressed the efficiency of absorption of calcium, magnesium, and zinc. Although ingestion of purified lactose, but not yogurt, improved apparent absorption of magnesium and zinc, the effect of lactose on calcium absorption is questionable. An effect of lactose on calcium absorption could only be observed among rats fed the high level of calcium if less rigorous statistical tests (LSDs) were applied. Diet digestibility was strongly correlated with apparent absorption of calcium, magnesium, and zinc. However, changes in the colon induced by the dietary treatments (i. e., pH and β-glucurondiase activity of colonic contents) were not correlated to apparent absorption of minerals. © 1990, American Chemical Society. All rights reserved.