"I mention this because of the altered states of mind Buddhist monks enter into during meditation"
Tibetan monks/nuns are (were) physically robust they have both dairy and barley in their diets, does this mean that they are less able to go into a trancelike meditation? Its a fascinating and vast subject diet, religion and its effect on people. For instance early celtic monks by isolating themselves in lonely places would probably only have lived on fish/seabirds, so did malnutrition/half starvation bring on all those "visions"?