Probiotics -Friendly Bacteria

Probiotic microorganisms are “Gram positive anaerobic bacteria and are included primarily in two genera, Lactobacillus and Bifidobacterium”. (WHO, 2001, pg7). They naturally occur in the human intestine (but not in new-borns). A example of a probiotic supplement is “inner health plus”, which contains the microorganisms Lactobacillus acidophilus and Bifidobacterium lactis and the prebiotic “colostrum powder” to sustain the organisms.

Currently in vitro tests are use to examine the ability of probiotics to function in humans. However , the available tests are inadequate to accurately “predict the functionality of probiotic microorganisms in the intestine”. (WHO, 2001, pg7)

Newborns have no bacteria in their gastrointestinal system. The modes of transmission for digestive microbes are primarily the diet. Microbes are present in uncooked fruits, vegetables, and dairy products. The first colonization of microbes in a newborn’s intestine are from breast milk. Website [3]. It is debated that the most important digestive microbes are lactic acid microbes (Lactobacillus). Microbes are labelled as friendly because they assist digestion, particularly of lactose. “Bacteria such as Lactobacillus…species have been used extensively in food processing throughout human history, and ingestion of foods containing live bacteria, dead bacteria, and metabolites of these microorganisms has taken place for a long time” (Norio Ishibashi and Shoji Yamazaki ,2001, page 1)

The pathogenicity of these microbes to the host have rarely been accounted for. If probiotics were found to be pathogenic and this “unfriendly” they would not be used in probiotic supplements. However, probiotic bacteria have been isolated from infected lesions. Lactic acid bacteria and bifidobacteria have been isolated from endocarditis, bacteremia, and bloodstream and local infections, which naturally occur in human intestines and thus are used in probiotics. “A generalised explanation of how lactobacillus and bifidobactirum have been found in infections is that they are the result of “oppotunistic infections”. (Norio Ishibashi and Shoji Yamazaki 2001, page 2). It is difficult to prove the pathogenicity of probiotic bacteria, because anaerobes are generally considered to not be pathogenic. (Norio Ishibashi and Shoji Yamazaki 2001, page 3) showed a proposed invasion mechanism for probiotic bacteria, where they travel through the mucosal barrier of the intestine and by translocation through the mesenteric lymph nodes or the portal vein they travel to organs and cause a pathogenic response. Berg, R. D., and D. C. Savage demonstrated this mechanism by looking at the “Immunological responses and microorganisms indigenous to the gastrointestinal tract” (GI) (Rodney D. Berg 1979 p1,8) using вЂ?gnotobiotic mice’. Some Lactobacillus species, are shown to cause tooth decay in the disease dental caries. Figure to the right sourced from website [2].

“Although the development of probiotics is still in its early stages, a better understanding of the normal microbiota in the large intestine of both animals and humans will be forthcoming as more microbiologists investigate probiotic activity.” (Lansing M. Prescott, 2002 pg703) . For example, the studies with Lactobacillus by Jeremy Nicholson and his colleagues with mice showed a beneficial change in the bile acids, which ended up favouring enzymes that reduced the amount of fat digested. If this industrial advancement through research and discovery became refined and commercialised it could help reduce obesity.

(Lloyd Cluff/Corbis,2008, pg 15)

Probiotic bacteria are friendly bacteria, because they naturally inhibit the reproduction of “unfriendly" bacteria in the gastrointestinal tract, which can be the causitive agents for bowel, vaginal, respiratory, and urinary tract infections.

Inner health plus probiotic supplement figure bellow. Sourced from website [4].

The way that probiotics maintain a balance of healthy bacteria in the GI tract and help inhibit “unfriendly” bacteria include:

пÑ"? “Competition for nutrients and adhesion sites (for colonies)

пÑ"? Inactivation of pathogenic bacterial toxins or metabolites

пÑ"? Production of substances that inhibit pathogen growth

пÑ"? Stimulation of nonspecific immunity” (Lansing M. Prescott, 2002 pg703)

Some of the other proposed benefits of probiotics include:

пÑ"? The inhibition of parasitic infections

пÑ"? Production of ОІ-galactosidase for alleviation of lactose intolerance (Ipek Goktepe, 2006, pg 20)

пÑ"? The metabolism of probiotic bacteria helps provide a variety of B vitamins (folic acid, B5, niacin, biotin, B12 and B6).

пÑ"? Cholesterol normalization. Through “cholesterol assimilation, modifcation of bile salt hydrolase activities and antioxidative effects.” (Ipek Goktepe, 2006, pg 20)

пÑ"? Improved digestion and absorption in the GI tract . This is one reason probiotic bacteria can help treat diarrhea and bacterial caused diarrhea. However, the resultant improved bowel motility can also offer relief from constipation. Probiotics also have antagonistic effects against antibiotic-associated diarrhea and irradiation-associated diarrhea. (Ipek Goktepe, 2006, pg 20)

пÑ"? There is strong evidence the (probiotic) organisms that due to production methods occur in yoghurt “alleviate the symptoms of lactose intolerance in lactase-deficient individuals.” This is due to the increase in lactase activity in the small intestine by lactic acid bacteria (Lactobacillus). (Marteau et al ., 1990)

пÑ"? Anti-carcinogenic . The consumption of probiotic bacteria in yoghurt has been shown, in recent epidemiological studies, to provide evidence for reduced colon cancer risk, “but definitive evidence is lacking “. (A Sullivan and C. E. Nord, 2005, pg 1)

The strongest evidence of a beneficial effect of defined strains of probiotics has been established using Bifidobacterium lactis of acute diarrhea