The impact of fluoridated milks on the availability of trace elements in milk

Background: Milk is a nutritious food and also used as a vehicle for fluoride (F) administration. However, the impact of added F on milk's nutritional profile is unknown. In vitro simulated gastrointestinal digestion with enzymatic steps was used to measure and compare the availability of trace elements (Fe, Zn, Cu, Cr, Mo and Se) in pasteurised skimmed (0.3% fat) and whole (4% fat) milk samples with four concentrations of F (0, 2.5, 3.75 and 5.0 ppm) as well as in non-F and F ultrahigh-temperature (UHT)-processed 4% fat milks. Post-centrifugation supernatant trace element concentrations were measured after each stage of digestion by inductively coupled plasma mass spectroscopy.
Results: F showed a negative effect on Cu availability in cow's milk. Fat removal increased the availabilities of Cu, Zn, Cr and Se but decreased the Mo availability. There was a greater Cr availability in the UHT milk sample compared with pasteurised samples.
Conclusion: These initial data suggest that adding F to milk does not have a marked effect on its trace element profile, with the exception of reduced Cu availability. However, these findings would benefit from further studies both in vitro and in vivo.