Dietary calcium and vitamin D2 supplementation with enhanced Lentinula edodes improves osteoporosis-like symptoms and induces duodenal and renal active calcium transport gene expression in mice.

The two main sources of vitamin D3 are de novo synthesis induced by exposure to ultraviolet (UV) light from the sun, and diet. Vitamin D3 deficiency causes rickets or osteoporosis. Oak mushrooms (Lentinula edodes) that are exposed to UV radiation contain enhanced vitamin D2 and have much higher calcium content than unmodified (non-irradiated) mushrooms.