Calcium Chloride and Vitamin D Fortified Beverages: Bioavailability in Wistar Rats

Abstract

Calcium and vitamin D deficiency is now recognized as an epidemic in the United States. Calcium and vitamin D play a critical role in the prevention of metabolic diseases including osteoporosis, osteomalacia, and rickets. Epidemiological research indicates that average intake of these nutrients is well below the RDA. Dairy products continue to be the main source of calcium intake. The major source of vitamin D is from sensible sun exposure. Greater intake of calcium and vitamin D has been correlated to a reduction in fractures, prevention of osteoporosis, and increased bone mass. The objective of this study was to test effects of a water-soluble form of vitamin D and calcium chloride as fortifiers for an aqueous sports drink solution with a rat bioavailability assay. A water-soluble vitamin D fortifying ingredient was prepared as a spray-dried complex with bovine beta-lactoglobulin. Vitamin D content of the complex was assessed by HPLC. Flavored beverages were formulated with various ratios of calcium and vitamin D in a 4x4 factorial design. Female Wistar rats were housed under incandescent lighting and randomly divided into the treatment and control groups. After a 4-week depletion phase, rats were given specialized drink formulations and low calcium, vitamin D-deficient diet for an additional six weeks. Blood and femur bones were removed for further analysis. Serum vitamin D was measured by ELISA. Results demonstrate that fortified drink solutions could be accurately formulated to contain calcium chloride at 0, 1, 2 and 2.5 g Ca/L with palatability to rats. The vitamin D content of the drinks was formulated to be 0, 10, 20, and 40 µg/L. Serum vitamin D was significantly greater (p< .0001) in rats receiving the vitamin D-fortified drinks. Water-soluble vitamin-D can be used to fortify aqueous products with this fat-soluble vitamin to help facilitate the uptake of calcium. Regular consumption of flavored sports drink fortified with calcium and vitamin D may significantly increase dietary calcium and vitamin D intake.