Impact of goat milk powdered formulations on mineral absorption, peak bone mass and bone loss due to ovariectomy in rats

BACKGROUND: Goat milk is recognised as nutritious, with benefits to growth and skeletal development. The initial aim of this study was to investigate the effect of three different goat milk formulae - a whole milk, a skim milk and a goat milk growing-up formula fortified with pre- and probiotics (Formula 1) - on mineral absorption and retention in rats. The effect of long-term intake of the fortified formula diet on peak bone mass and post-ovariectomy bone loss in rats was then investigated in a follow-up study and was assessed by bone density dual-energy X-ray absorptiometry and biomechanical testing of bone ex vivo. RESULTS: Goat whole milk and fortified milk formulations improved calcium and phosphorus absorption and retention. Body composition analysis showed that rats fed the fortified diet had higher body calcium and phosphorus content. The fortified diet was then tested in a long-term feeding trial. Rats fed the fortified diet from weaning had a higher peak bone mass than rats fed a soy protein control diet. Bone mineral content (BMC) and density (BMD) of the lumbar spine were higher in rats fed the fortified diet. After ovariectomy, all rats lost bone mass, but rats fed the fortified diet maintained significantly higher BMD and BMC values throughout the trial, though still lower than those of non-ovariectomised control rats. The fortified diet increased bone strength. CONCLUSION: Goat milk specific nutrients supported by pre- and probiotics in Formula 1 may improve mineral status during growth and support attainment of peak bone mass. (c) 2008 Society of Chemical Industry.