Effects of vitamin D 2 -fortified shiitake mushroom on bioavailability and bone structure.

Bioavailability and bone loss inhibitory effects of vitamin D2 derived from UV-irradiated shiitake mushroom were determined in vivo. The effect of the absence of ovaries on the bioavailability of vitamin D2 and bone structure was also investigated. Sham operated (sham) and ovariectomized (OVX) rats were divided in 3 groups according to their diets, i.e. control: only vitamin D-deficient diets; UV(X): vitamin D-deficient diets with non-irradiated mushroom powder; UV(O): vitamin D-deficient diets with irradiated mushroom powder. The obtained results showed that vitamin D2 from shiitake mushroom was able to increase bone mineral density and trabecular bone structure of femur bone as well as its bioavailability. The absence of estrogen induced adverse effects not only on bioavailability of vitamin D2 but also on trabecular bone. In conclusion, vitamin D2 -fortified shiitake mushroom might help postmenopausal women increase vitamin D2 bioavailability and retard trabecular bone loss. Abbreviations: OVX: ovariectomized; 25(OH)D: 25-hydroxyvitamin D; 1,25(OH)2D: 1,25-dihydroxyvitamin D; BMD: bone mineral density; micro-CT: micro computed tomography; RSM: response surface methodology; RP-HPLC: Reverse phase-high performance liquid chromatography; MS/MS: tandem mass spectrometry; E2: estradiol; NTx: N-terminal telopeptide of type I collagen; BV/TV: bone volume/total volume; BS/BV: bone surface/bone volume; Tb.Th: trabecular thickness; Tb.Sp: trabecular separation.