Bioavailability of calcium is equivalent from milk fortified with either calcium carbonate or milk calcium in growing male rats

Absorbability of calcium from milk and a variety of calcium salts has been a significant focus of studies over recent years. The present study compared the bioavailability of calcium from skim milk fortified with calcium carbonate or milk calcium, using young growing male rats. Primary outcomes were bone mineral density, bone calcium content, bone breaking strength and urinary excretion of collagen cross-links, a measure of bone resorption. Results showed that there was no significant difference in any of the measured parameters. The implication is that the kind of calcium salt used for fortification is not the determining factor for bioavailability. This agrees with various human studies, which have shown that different salts are absorbed to similar extents. Calcium fortified food products or milk is a convenient option to increase dietary calcium intake.