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Tuesday, December 7, 2010

Are Probiotics Safe and Effective?

Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. In the USA, probiotics are marketed as foods or dietary supplements. For dietary supplements, premarketing demonstration of safety and efficacy and approval by the Food and Drug Administration are not required; only premarket notification is required and the manufacturer is responsible for determining its safety.

The live organisms commonly used as probiotics are: Lactobacillus spp. (eg, L. acidophilus , L. casei , L. rhamnosus , L. bulgaricus), Bifidobacterium spp. (e.g., B. bifidum , B. longum), Saccharomyces boulardii , and Streptococcus salivarius.

Common uses of probiotics include treatment of acute/infectious diarrhea, antibiotic-associated diarrhea, immunity/allergy, respiratory and urinary tract infections, and vaginosis. Each agent or preparation may have unique actions. The mechanisms of action of probiotics are production of pathogen-inhibitory substances, inhibition of pathogen attachment and toxins production, stimulation of immunoglobulin A, and nutrient effect on intestinal mucosa.

Oral preparations of probiotics (tablets/capsules/liquid) can deliver billions of live bacteria in each ingested dose. Many yogurt brand contain live probiotic bacteria. However, the quantity of these bacteria in yogurt is much smaller than in oral probiotic preparations.

Despite the widespread availability of probiotic products, few commercially available preparations are supported by placebo-controlled, double-blind studies, and the results of in vitro studies cannot be extrapolated to in vivo situations.

Although generally believed to be safe with few side effects, oral preparations of probiotics should be avoided in people with intestinal damage, a weakened immune system, or with overgrowth of intestinal bacteria. This may include individuals who are receiving chemotherapy. In these patients these bacteria can cause serious and sometimes life threatening complications. This is why individuals should consult their physician whenever live organisms are ingested. This is especially important in those with the above conditions.

Oral preparations of probiotics (Tablets/capsules/liquid/) can deliver billions of live bacteria in each dose. Many yogurt brand contain live probiotic bacteria. However, the quantity of these bacteria in the yogurt is much smaller than in oral probiotic preparations.