**7.1 Vitamin D and the positive point**

Vitamin D is easy to use and available. Its cost is not so much, and it may be prescribed as an efficient strategy in hindrance and/or prevention of space-induced changes (particularly in bone) [21].

## **7.2 Vitamin D and the negative point**

An important subject that should be considered is vitamin D does not have an infinite capacity for preventing osteoporosis (cellular process) [22].
