The gastrointestinal (GI) tract of the fetus is sterile and bacteria are introduced from the mother as the baby passes out of the birth canal. The baby has a regular supply of bacteria within a few months, which are termed microflora, and live in a complex relationship with the cells that line the gastrointestinal tract. An adult has about 100 trillion microflora cells.

Probiotics are defined as “living organisms in food and dietary supplements, which upon ingestion, improve the health of the host beyond their inherent basic nutrition”. Probiotics are commonly lactic acid bacteria and prebiotics are carbohydrates that improve the health of microflora when taken as supplements. Prebiotics inclute lactosucrose, fructo- and galacto-oligosaccharides, inulin, psyllium, bran, and germinated barley. Synbiotics are combinations of probiotics and prebiotics. The prebiotics are of benefit in the growth of probiotics. Inulin has been shown to improve the growth of Bifidobacterium animalis.

The intestinal microflora benefit the person by producing vitamin K, saving energy from undigested food, inhibiting the growth of pathologic bacteria, maintaining the health of the lining of the GI tract, and helping maintain immunity at the level of the lining cells of the GI tract. The microflora cells and the lining of the intestinal tract live in a complex relationship of mutual benefit. There are mechanisms by which the microflora do not stimulate the body’s immunity and, therefore, are allowed to survive because the immune system seems to ignore the microflora.

The effect of probiotic supplementation has been studied in a number of disease processes. Probiotics enhance the “barrier function” of the wall of the intestine, which prevents pathologic bacteria, such as E. coli, from penetrating the intestinal wall. Probiotics limit the growth of pathologic bacteria by limiting the space available for these pathologic bacteria to grow and also secrete substances that inhibit the growth of pathologic bacteria. Probiotics can produce conjugated linoleic acid (CLA) with anti-inflammatory and anti-cancer effects.

Inflammatory bowel disease (IBD) is believed to be the result of hyperactivity of the body’s immune system to intestinal microflora in people who are genetically susceptible. In IBD there is a disruption of the types of microflora that are normally found in the bowel. There have been a number of studies attempting to treat IBD with probiotics and prebiotics and the studies do show promise in Crohn’s disease and ulcerative colitis.

A probiotic cocktail called VSL#3 contains the following:

Lactobacillus acidophilus.

L. bulgaricus.

L. casei.

L. plantarum.

Bifidus breve.

B. infantis.

B. longum.

Saccharomyces thermophilus.

This combination of probiotics has been shown to convert linoleic acid to conjugated linoleic acid (CLA), which has anti-inflammatory and anti-cancer effects.

CONCLUSION: Probiotics have been shown to improve the health of the inner lining of the intestine, reduce inflammation, and prevent pathologic bacterial invasions. There is a known connection between inflammatory disease and probiotics. Further testing is needed to find out which specific probiotics and prebiotics are helpful in specific disease processes.

PMID: 17009391.

Summary #107.