The Probiotics Revolution is a very informative book that discusses the importance of having a proper amount of probiotics in the diet. A large portion of the immune system is in the gut. When the gut is not functioning properly, the immune system will not function properly. Probiotics help to improve the functioning of the immune system.
There must be a balance of good bacteria and bad bacteria in the gut. Fermented foods such as yogurt, keifer, and sauerkraut help to balance the flora in the gut.
The Probiotics Revolution by Dr. Gary Huffnagle is an excellent book that discusses the importance of probiotics. It explains how antibiotics can disrupt the good bacteria in the gut. Dr. Huffnagle also explains how probiotics can possibly help to improve conditions such as asthma, IBS, Autoimmune Disorders, and other issues.
The following is a link to an excerpt for The Probiotics Revolution: