How Important Are Probiotics?

Probiotics are live bacteria, yeast or viruses that promote health when they are ingested in adequate amounts. The word probiotics is a blend of the Latin "pro," which means "for" and the Greek "bios," which means life. Probiotics can help restore the natural balance of beneficial and harmful bacterial in the gastrointestinal tract that may have have been upset by infection, antibiotic therapy or diseases of the immune system. Probiotics are dietary supplements, usually in capsule form, and are generally very safe. If you're thinking about taking probiotic supplements, check with your doctor first.

Probiotics and Diarrhea

Countless generations all over the world have consumed probiotics in the form of fermented milk, soy products and juices. Yogurt contains several varieties of Lactobacillus, Streptococcus boulardii and Bifidobacterium (also called Lactobacillus bifidus) and other bacteria that help restore normal levels of health-promoting bacteria in the bowels. A 2003 study published in the journal "Clinical Microbiology Reviews" found that probiotics containing Lactobacillus species reduced the duration and severity of rotavirus-induced diarrhea in children. The researchers suggested four possible ways probiotics may help: blocking the effect of toxins generated by rotavirus infection, stimulating the body's immune system, reducing secretion of substances by the gut that stimulate bowel movements or directly inactivating the virus.

Inflammatory Bowel Diseases

Crohn's disease, ulcerative colitis and pouchitis are examples of inflammatory bowel diseases that may respond positively to probiotic therapy. A 2003 review published in "Postgraduate Medical Journal" found that probiotics containing healthy strains of E. coli, S. boulardii or Lactobacillus casi reduced inflammation in Crohn's disease subjects. The same review found evidence that the E. coli strain Nissle 1917 was as effective as drug therapy in producing ulcerative colitis remission. No one probiotic microorganism works in all cases; combinations of microorganisms are more effective.

Probiotics and Food Allergies

A 1997 study published in the "Journal of Allergy and Clinical Immunology" found that probiotics containing Lactobacillus GG were effective in treating food allergy in infants. The researchers treated 31 infants diagnosed with cow's milk allergy and atopic eczema. The infants were placed on a milk-elimination diet and given hydrolyzed whey formula with or without Lactobacillus GG for two months. After the trial period, the children were tested for their reaction to cow's milk skin pricks. The researchers found that only 30 per cent (eight) infants still tested positive for cow's milk allergy. The study also found that the infants' intestinal inflammation and eczema decreased in response to Lactobacillus GG therapy.

Probiotic Safety

A "British Medical Journal" review published in 2006 concluded that the benefits of probiotic therapy outweighed any possible health risks. The researchers focused on studies involving Lactobacilli- and bifidobacteri-containing products. They reported a few cases of bacteremia -- bacteria in the blood -- resulting from treatments of Lactobacillus GG or Lactobacillus casei. They concluded that the condition of bacteremia was easily treatable and the risk from taking probiotics was "negligible."

The National Center for Complementary and Alternative Medicine's website concludes that while the side effects of probiotics in general are mild, some individuals may experience more serious consequences related to immune system stimulation and unhealthy metabolic activity. In addition the center raises the possibility of gene transfer -- harmful genetic material from probiotics being incorporated into normal intestinal bacteria.