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Pharmacy and Medications




Hi guys, I always take probiotic as a supplement. I wonder which strain is the best one, the one that resembles the actual bacteria in the intestine, as there are so many strains in the pharmacy and whether the refrigerated one is better than the dry one.

Besides, I still don’t understand why the bacteria in those supplements still stay alive so that it later grows in the intestine after being exposed to acid in the stomach and alkaline in the intestine and why it is not absorbed into the blood stream after digestion. Thanks.


Probiotics are live organisms, usually bacteria and yeast, that when taken appropriately and in adequate quantities may have beneficial health effects. Two of the best studied probiotic bacterial species are the bifidobacteria and lactobacilli, both of which are common and desirable inhabitants of the human GI tract. A third commonly used probiotic is the yeast Saccaromyces boulardii.

Bacteria of all sorts are naturally present in and on the human body, mainly in the gastrointestinal tract, on the surface of the skin and mucus membranes. The human intestine provides food and shelter to approximately 300-500 different species of bacteria. With so many different bacteria living and interacting, a complex ecology develops. When the normal ecology of the GI tract is disrupted, for example, after therapy with certain antibiotics, or when new bacteria are introduced due to travel, some bacteria may overgrow leading to various disease states. The main goal of taking probiotics is to maintain, restore or modify the normal gastrointestinal ecology.

Probiotics contain living organisms. Proper storage is necessary to increase survival of the organisms in probiotic products. Some of the available probiotics are dairy products like yogurt and kefir. Some products need refrigeration and some do not. The manufacturer of the particular product should include proper storage instructions on the labeling. In general, even if these products are stored according to the instructions on the label, they should not be used beyond their expiration date.

Stomach acid is one of the body's defenses against bacteria. However, it is clear that some bacteria like Bifidobacterium species are able to survive this defense to ultimately take up residence in the digestive tract. Some probiotic products have been manufactured with enteric coating or encapsulation that may protect them from the harsh environment of the stomach.

The question as to which probiotic product is best is difficult to answer. There is probably no good reason for a normal healthy individual to take probiotic products regularly to maintain bowel health. This does not mean that there is anything wrong with regular consumption of dairy products like yogurt that contain live lactobacillus cultures. There is reasonably good evidence that taking some probiotic products can prevent or minimize the diarrhea sometimes associated with antibiotic use. Yogurts and kefirs that contain the National Yogurt Association's "Live and Active Cultures seal" on the label should provide an adequate source of lactobacilli for this purpose. Most of these dairy based products require 2 eight ounce servings daily when used for this purpose.

It is important to realize that the calcium in yogurt and other dairy products may reduce absorption of some antibiotics. For this reason it is best to take the antibiotic one hour before or two hours after the probiotic. Probiotics that contain Lactobacillus GG (Culturelle, others) or Saccaromyces boulardii (Florastor) are also likely to help in this situation. These probiotics may also be used to minimize travelers' diarrhea. To work for this use, these probiotics should be started a few days before the trip and continued for the entire trip.

Probiotics may be beneficial for treating or preventing disease in other parts of the body (i.e. bladder, respiratory tract and vagina). Some of the benefit could be due to a positive effect on the immune system. To date, clear evidence of a significant beneficial effect is unavailable. Ongoing research should help to further define beneficial bacterial strains and the disease states for which they may provide a positive action.

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Response by:

Robert James Goetz, PharmD, DABAT
Assistant Professor of Pharmacy Practice
College of Medicine
University of Cincinnati