The brain-gut connection is very much benefitted by kefir. Balancing pH and reducing the potency of harmful bacteria in the body, it produces a more streamlined form of digestion.
A trick is to mix or consume with lard. The fat in lard creates a more soluble environment in the lower intestine, enabling maximum absoprtion of the vitamins and minerals in kefir (of particular note are vitamin A, D, phosphorus, riboflavin and magnesium). Vitamin A & D are fat soluble, and so are more easily abosorbed and assimilated by the presence of lard in the body.
My favourite brand:
Edit: In addition, the potassium content of kefir is beneficial for joints, rheumatoid arthritis and balancing the level of sodium in the body primarily consumed from salt.