Probiotics are microbial food supplements that improve health by altering intestinal microbial balance. Several pounds of bacteria reside in the intestines, and it is important to cultivate the beneficial bacteria, rather than pathogenic bacteria. The beneficial bacteria cause lactic acid production and fermentation. The changes in the colonic environment make it less favorable for pathogenic bacteria to live. In addition, butyric acid and other short chain fatty acids are produced, which are used by the colonocytes (cells lining the large intestine). Beneficial bacteria can also produce some vitamins (e.g., B12, pantothenic acid, biotin, K).
RDA (Recommended Dietary Allowance) for Adults
Fermented foods (especially yogurt) and supplements.
1 billion to 10 billion CFUs (colony-forming units).
POSSIBLE THERAPEUTIC APPLICATIONS
Cancer (colon), diarrhea (from contaminated food and water), eczema (infants), immune function, irritable bowel syndrome, yeast infection.
To make yogurt, a culture containing the bacteria Streptococcus thermophilus and Lactobacillus bulgaricus, and sometimes Lactobacillus acidophilus, are used. Some yogurt products will not have live beneficial bacteria present. Antibiotic therapy often reduces the population of beneficial bacteria. Lactobacillus species reside in the vagina and can help with various problems. Lactobacillus bacteria need to reach the second half of the small intestine (ileum) alive, and Bifidobacteria bacteria need to reach the large intestine (colon) alive. Use supplements that are enteric coated (protected from stomach acid), or take between meals, or take with food that is low in protein and fat. And use prebiotics, such as FOS (fructo-oligosaccharides) and inulin, which serve as food for the beneficial bacteria. Good sources of prebiotics-containing foods are asparagus, bananas, chicory, Jerusalem artichokes, and onions.
None significant, but consult with your health practitioner if you are severely immune compromised (e.g., HIV/AIDS).
I find this interesting reading. The two biggest problems probiotics have had are strength and delivery.
Strength: how can 1 billion CFU compete with 10 trillion indigenous organisms? If stomach acid is a barrier for pathogens to reach the intestines, then how can that 1 billion organisms (that might lose 99% in the stomach acid) begin to work? 10-20 billion through the stomach will show some results.
Delivery: this relates to 2 issues, in the bottle and through the stomach. The manufacturer can guarantee a billion CFU when they make the capsule. If it is in plastic, stored at room temperature with a bit of humidity, the organisms can be dead in a matter of hours. They still met the guarantee and the consumer got dead organisms. Look for a guarantee through expiration.
Delivery through the stomach is another matter. You can coat them with polyacrylic enteric materials, compress them into hard calpets or small beads (heat, humidity, pressure . . . not good for any living thing) or rely soley on the natural resistance some organisms have. There are other ways using gums and alginates.
You can rely on single strain products which cover only half of the GI Tract (Lactobacilli in the small intestine and Bifidobacteria primarily in the colon), you can assume the strains are truly probiotics (some cultures only make cheese or yogurt and might still Lactobacilli) visit
http://www.internationalprobiotics.org/consumers.aspx for a list of probiotic strains, or you can merely accept manufacturer claims. Look for some indication of activity (Lactic acid production).
I believe probiotics are as important as vitmains and should be taken as part of a lifelong program for intestinal health. Everyone should do the research to find the good ones. Don't accept those adding a few organisms to an herbal preparation or a food to get a higher price for their product. Don't accept those that do not give a guarantee through expiration. Don't accept those that do not require or recommend refrigeration. Look for companies that offer third party independent analysis online by lot or some real (not marketing) information.
Which is better, spending a $20.00 for a weak ineffective product you need to take with every meal every day, or $40.00 for a product that is taken daily or less often and is well researched. Look for marketing tricks. A product may guarantee 1 billion per gram. Each capsule contains 1/2 gram. Makes you think each capsule is stronger than it truly is. The consumer needs to think, do some homework and then titrate themselves to find the best dosing for maximum benefit.