Background information for lactic acid producing bacteria
The role of lactic acid bacteria in gastrointestinal microecology (the pounds of bacteria that live on us and within us) has been the subject of extensive research. It is widely believed that these bacteria prevent the growth of putrefactive microorganisms responsible for ill health by competitive inhibition (crowding them out), by the generation of a non-conducive acidic environment which inhibits the growth of infectious bacteria, and/ or by the production of antibiotic-like substances called bacteriocins which control the growth of infectious bacteria such as yeasts. Their metabolites may include B complex vitamins. Their enzyme activities improve the digestion and absorption of ingested nutrients. Lactic acid bacteria also colonize the skin and mucus membranes and play an important role in preventing bacterial and fungal infections of the skin and genito-urinary tract. Lactobacilli have a protective role against vaginal infections. They utilize glycogen in the vaginal epithelial cells to produce lactic acid which helps to maintain the pH of this environment between 4.0 and 4.5. This pH creates a non-conducive environment for the growth of pathogens like Candida albicans, Trichonomas vaginalis and some of the non-specific bacteria, which are responsible for vaginal infections.
An adverse imbalance among intestinal bacteria with a marked reduction in lactic acid bacteria and an increase in putrefactive pathogens in the fecal flora has been observed in conditions like food allergy and eczema. The beneficial role of lactic acid organisms in preserving intestinal integrity and health has been documented extensively.
There has been an increasing interest in the relationship between intestinal microflora and their effects on the health of the human host. The ecosystem of the human gastrointestinal tract is extremely complex, colonized by more than 500 species of bacteria. Although lactobacilli in general represent a smaller percentage of the intestinal flora, their metabolic functions make them important. On colonization of the germ-free gastrointestinal tract in the human infant, shortly after birth, with normal gut flora, 2.4% are lactobacilli. The species of lactobacilli normally present include L. bifidus (Bifidobacterium bifidum), L. acidophilus, L. casei, L. fermentum, L. salivarius, L. brevis, L. leichmanii, L. plantarum and L. cellobiosus. About one third of the fecal dry weight consists of bacteria.
Populations at high risk for colon cancer have been found to harbor gut flora which efficiently metabolize steroids and hydrolyze glucuronides releasing toxins from the stool and recycling them. A diet containing large amounts of viable lactobacilli significantly lowered these activities in these individuals. The normal fecal flora in humans includes the following organisms:
| Microorganism |
Viable colonies
(per gm. of fecal matter) |
| Escherichia coli |
1million - 1 billion |
| Clostridium perfringens |
0-1 million |
| Streptococci |
1000-1 billion |
| Bacteroides |
1million - 1 billion |
| Lactobacilli |
10 million -10 billion |
In the process of performing their metabolic activities in the human gastrointestinal tract, these microflora convert complex ingested food constituents into easily digestible forms, perform detoxification processes, and produce metabolites of nutritional and therapeutic significance to the host. A delicate balance exists in the symbiotic relationship (mutually beneficial) between microflora and the human host.
The composition of the intestinal microflora is constantly changing, being influenced by factors such as diet, emotional stress, age and treatment with antibiotics or other medications.
In general, lactobacilli are acid tolerant and can survive and proliferate at low pH in the stomach. An optimal "balance" in the gastrointestinal microbial population is associated with good health in humans. This balance between beneficial bacteria and potentially harmful bacteria is referred to as EUBIOSIS.
In view of the pressures of modern existence, the maintenance of a normal, healthy, balanced microbial population (EUBIOSIS) in the gastro-intestinal tract is a difficult task. Humans are often subjected to various stress conditions such as changes in food consumption patterns, vagaries of the weather, extensive travel and somatic diseases that necessitate treatment with antibiotics and immunosuppressive drugs. Under such adverse circumstances, the harmful bacteria may become predominant (a condition referred to as bacterial overgrowth) and create an imbalance which may in turn impair normal gut function and lead to various problems, ranging from inefficient digestion, diarrhea, constipation, and flatulence to severe gastro-intestinal disorders.
A logical approach to restoring the balance of intestinal flora is the use of probiotics. The reported health effects of these preparations include effectiveness in the treatment of a variety of disorders including colitis, constipation, diarrhea, flatulence, gastric acidity, gastroenteritis, and in recolonization of the intestine with beneficial flora after treatment with antibiotics.
Various species of lactobacilli have been examined including L. bulgaricus, L. bifidus, L. acidophilus, L. casei, L. brevis and S. thermophiles. L. acidophilus, long regarded as the best candidate for therapeutic use, has been shown to be ineffective in alleviating certain gastrointestinal disorders. Besides, it produces D (-) (levorotatory) lactic acid, which is not an effective antagonistic agent against infectious microbes.
A superior species among Lactobacillus is L. sporogenes. This species forms spores, which on activation in the acidic environment of the stomach, can germinate and proliferate in the intestine, produce the favored L (+) form of lactic acid and effectively prevent the growth of pathogens. In effect, the process can be equated to the slow release of viable cells, leading to prolonged and effective beneficial microbial activity. L. sporogenes spores are slowly excreted out of the human system, long after the termination of therapy.
In view of the fact that the World Health Organization (W.H.O.) has recommended restricted intake of D (-) lactic acid for adults and total avoidance of the use of this form of lactic acid in infant nutritional products, L. sporogenes* is the Lactobacillus favored in infant nutritional programs.
LactoSpore®, a preparation containing viable spores of B. coagulans, is a registered trade mark of SABINSA CORPORATION. B. coagulans preparations in powder, tablet and capsule forms have been used in successful clinical trials in the treatment of gastrointestinal disorders, vaginal infections, hypercholesterolemia, lactose intolerance, and as an adjuvant to antibiotic therapy.
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