Reduction of the bioavailability of fluoride from Antarctic krill by calcium

The bioavailability of fluoride from krill exoskeleton and the effect of additional calcium on the bioavailability of fluoride from krill paste were evaluated using young rats. Fluoride from the exoskeleton showed a high apparent absorption of 80%. Approximately 3.6% of this fluoride was deposited in the femur, and 44% in the rest of the carcass. The presence of 1.5% and 2.5% calcium (CaCO3) in the diet--1.0 and 2.0% above the minimum recommended content respectively--significantly reduced the bioavailability of fluoride from krill paste. The apparent absorption of fluoride from the paste was reduced by 33.8 and 45.8%, deposition in the femur by 48.1 and 58%, and retention in the rest of the carcass by 44.4 and 55.6%, respectively. The need for further studies using lower amounts of fluoride and calcium and other chemical forms of calcium is indicated.