!) Has your friend received an actual diagnosis from a medical doctor or is he buying into some abusive juice-fast "authority" and trying to live by a form of dogmatic self-denial that will leave him malnourished, drained, low on protein, and anorexic due to spiritual beliefs? (Spiritual anorexia is as dangerous -- although, blessedly less common than -- body dismorphic anorexia.)
2) "Leaky gut syndrome" is a controversial conflation of a number of diseases, some genetic (e.g. psoriasis) and some environmental (e.g. hives). The appeal of "leaky gut syndrome" to hypochondriacs, and its abusive use by false authority figures in the "alternative medicine" world is easily perceived when you see and read web sites that basically scream out for new victims. Here's an example:
Do you have:
arthritis
allergies
depression
eczema
hives
psoriasis
chronic fatigue syndrome or
fibromyalgia?
Then you may also have Leaky Gut Syndrome!
The potential for abuse here is so obvious that it simply screams "BEWARE!"
3) We cannot diagnose medical conditions in this forum. If your friend has a serious bowel disorder, he should receive treatment for it. Since he was healthy previously, i advise him to return to the diet he ate while healthy, and to simultaneously make an appointment with a legitimate medical doctor, an M.D., as soon as possible.
4) My favourite spirit to work with when a friend needs an accurate medical diagnosis and an effective treatment plan is Dr. Jose Gregorio Hernandez. I simply cannot say enough about the blessings, medical healings, and spiritual help that have come from working with him. Light three dressed vigil candles -- a Dr. Jose Gregorio Hernandez candle, a Healing Miracle Candle, and a Clarity Candle (or thee white offertory candles, individually dressed with Dr. Jose Gregorio Hernandez Oil, Healing Oil, and Clarity Oil) -- in a triangle, with his picture (either face-up or in an easel-stand frame) in the middle. Place upon or right in front of the picture a small glass bowl containing these roots and herbs:
John The Conqueror (for male strength)
Self-Heal (for the recuperative powers of the body)
Angelica Root (for the help of the Archangel Raphael, the Healer of God)
Flax Seed (for clearing away any and all digestive problems)
Peony Root (for health and longevity)
Golden Seal Root (for health)
Life Everlasting (for long life)
Burn the candles continuously until they go out if you use vigil lights, or in sections, morning and night for seven days, if you use offertory candles. Pray for the aid of all good and kind spirits, including Dr. Jose Gregorio Hernandez, Archangel Raphael, and your friend's own Guardian Angel. See the prayer of Dr. Jose Gregorio Hernandez here:
http://luckymojo.com/drhernandez.html
Collect the roots and herbs and place them in a white flannel or unbleached muslin mojo bag. If you do not know how to make and tie a mojo, you can read more here:
http://luckymojo.com/mojo.html
Give the mojo to your friend to carry on his person. This will not only assist his health, but it will lead him to seek a better diagnosis and some effective treatment.