Absorption of calcium from the carbonated dairy soft drink is greater than that from fat-free milk and calcium-fortified orange juice in women

This study reports the intestinal calcium absorption of a new product that combines calcium and other nutrients from milk and the consumer's desire for soft drinks. The overall objective was to compare calcium absorption of commercially available products, the dairy soft drink, fat-free milk, and calcium-fortified orange juice using a randomized crossover design. Thirty-four women were studied, and fractional absorption of calcium, using stable isotopes of calcium, was used to determine intestinal absorption from the dairy soft drink, fat-free milk, and calcium-fortified orange juice. The influence of baseline calcium intake on intestinal absorption was also investigated and controlled for in the statistical analysis. Calcium absorption from the dairy soft drink was greater (43% ± 10%) than both the fat-free milk (35% ± 8%) and calcium-fortified orange juice (36% ± 11%) groups (P < .001). There was no difference between the fat-free milk and calcium-fortified orange juice groups. Fractional calcium absorption was inversely associated with baseline calcium intake within each product (all P < .05). It is theorized that the product's carbonation in combination with the milk components led to an increased calcium absorption compared with other food sources of calcium.