I know of a very distinct connection between spirituality and health. It's in your chakra system. For those who don't know, the chakra are a part of Eastern spiritual practices, philosophies, and medical treatments.
To explain the connection, I must first explain what the chakra are. The chrakra are the 7 points on the body from where the human body gets its massive energy from. They are the celestial batteries we are plugged into.
The energy created from these points are fed into the bioetheric aura of the body as well as the bioetheric channels where the meridians are accessed (the meridians are acupuncture points). A fundamental of Reiki (Eastern energy healing) is that the chakra effect the aura and vice versa. When the chakra are out of balance for whatever reason, the result is illness and/or pain.
Let me give you an example of how this works. What causes your typical illnesses? Most people would say germs and/or bacteria in the body. While this is definitely true, there is more to it than that. Germs and bacteria are always present in the body. In fact, our digestive system depends on it. What determines our level of health, despite them, is the effectiveness of our immune system which is powered by the chakra like all other bodily functions. When the chakra fails to feed the proper amount of energy to a certain area of the body, you'll probably get sick or begin feeling pain there.
In short, you have a shield of energy wrapped around you that is fed by a bunch of spinning vortexes that are centered over the major nervous system points in your body. When one goes awry, you get sick.
Now, let's connect them to spirituality and religion. The chakra that most commonly associates with spirituality, meditation, prayer, and even psychic ability is the brow chakra, also known as the "3rd eye" located on your forehead. When a person's brow chakra is "over-active" the energy output becomes excessive, thus strengthening the person's spiritual sensativity and generally strengthening their body's energy output and theoretically boosting the immune system in the process. When this happens, the aura produces the proverbial angel's halo around the head of the person. For someone whose eyes have been conditioned to see the aura, this halo can be seen and observed with the naked eye. For centuries, this has been a common mark of the spiritually evolved. Now you know why!
Ref: Chakra for Beginner, by David Pond
Aura Reading for Beginners, by Richard Webster
The Healer's Manual, by Ted Andrews