I don't think it's right to ask if one believes in spirituality; although religion was born from spirituality, it has lost its true meaning in the sense that religion is based 'tales' - I.E. from books and word-of-mouth. Spirituality can be interpreted in many ways, but to me it is based internally. There's no conforming to majority influence involved in spirituality, it's not a cult - there is nothing expected from you.
Belief is not quite the right word, agreed. As the Wiki article suggests it is a very broad concept. It does encompass every sort of religion and none I guess if I defined the word it would be a belief that one can transcend to something more than the mere physical. I would include relaxation, yoga and many meditative techniques under its umbrella, quiet meditative walks where one communes with nature. Seen in that diverse scale I think that it will improve ones physical and mental health.