There is a decline in the level of Vitamin D and Klotho during
ageing and this may be related to the age-related decline in the
ability of human skin to synthesize Vitamin D [108]. Vitamin D
deficiency may contribute to the ageing process through dysregulation
of cell signalling pathways such as those regulated by
mTORC1 and the Ca2þ and redox cell signalling pathways. Dysregulation
of Ca2þ signalling, which is closely linked to mitochondrial
dysfunction and ROS formation, has been implicated in ageing