Over 80 percent of the body's immunity is built in the intestinal tract by the friendly bacteria balance that resides there. The intestinal flora starts building in an infant while in the womb but doesn't really take off until after eight days of age. Starting with the colostrum milk, the gut begins to populate with more bacteria while the infant's immune system starts an inventory of good and bad cells in the body. This inventory is a life-long process and the immune system never forgets an invader.
The absolute worst thing to do to any infant is to give them an antibiotic. Antibiotics indiscriminately kill bacteria, both good and bad. One round of antibiotics will permanently change the baby's immune system, and because a majority of neuro-chemicals are also made in the gut, the baby's neurology is also altered .... http://www.naturalnews.com
