Probiotics, which means "for life", have been used for centuries as natural components in health-promoting foods. The original observation of the positive role played by probiotics. It suggested that utilizing probiotics it would be possible to modify the gut flora and to replace harmful microbes by useful microbes. The ageing process is exacerbated by resulting activity of putrefactive (proteolytic) microbes producing toxic substances in the large bowel. Proteolytic bacteria such as clostridia, which are part of the normal gut flora, produce toxic substances including phenols, indols and ammonia from the digestion of proteins. these compounds can be responsible for what is called “intestinal auto-intoxication”, which causes exaggerated physical changes associated with aging. It is known that milk fermented with LAB (Lactic Acid Bacteria) inhibits the growth of proteolytic bacteria because of the low pH produced by the fermentation of lactose, that consumption of fermented milk can “seed” the intestine with harmless LAB and decrease the intestinal pH, and that this would suppress the growth of proteolytic bacteria. Bifidobacteria would displace the proteolytic bacteria that cause the disease.
Considerable success in acute cases of infectious intestinal diseases (salmonellalosis and shigellosis). Escherichia coli is still in use and is one of the few examples of a non-LAB probiotic.
The term “probiotics” is described as growth promoting factors produced by microorganisms (protozoa). Contrasting antibiotics, probiotics can be defined as microbially derived factors that stimulate the growth of other microorganisms. A definition of probiotics which has been widely used: “A live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance, the definition emphasizes the requirement of viability for probiotics and introduces the aspect of a beneficial effect on the host.
Lactobacillus species have been introduced including Lactobacillus rhamnosus, Lactobacillus casei, and Lactobacillus johnsonii, because they are intestinal species with beneficial properties.
Effects
It is hoped, however, that probiotics do form beneficial temporary colonies which may assist the body in the same functions as the natural flora, while allowing the natural flora time to recover from depletion. The probiotic strains are then thought to be progressively replaced by a naturally developed gut flora. Hence, probiotics have been defined as correctives of the ecoorgan. If the conditions which originally caused damage to the natural gut flora persist, the benefits obtained from probiotic supplements will be short lived.
Potential benefits
Experiments into the benefits of probiotic therapies suggest a range of potentially beneficial medicinal uses for probiotics. For many of the potential subjects-patients.
Prevention of Colon Cancer
In laboratory investigations, some strains of LAB have demonstrated anti-mutagenic effects thought to be due to their ability to bind with heterocyclic amines; carcinogenic substances formed in cooked meat. Animal studies have demonstrated that some LAB can protect against colon cancer in rodents, that the strains tested may exert anti-carcinogenic effects by decreasing the activity of an enzyme called ß-glucuronidase] (which can generate carcinogens in the digestive system). Lower rates of colon cancer among higher consumers of fermented dairy products have been observed in some population studies.
cholesterol Lowering
Animal studies have demonstrated the efficacy of a range of LAB to be able to lower serum cholesterol levels, presumably by breaking down bile in the gut, thus inhibiting its reabsorption (which enters the blood as cholesterol).
Lowering Blood Pressure
Several small clinical trials have shown that consumption of milk fermented with various strains of LAB can result in modest reductions in blood pressure. It is thought that this is due to the ACE inhibitor-like peptides produced during fermentation. Improving Immune Function and Preventing Infections
LAB are thought to have several presumably beneficial effects on immune function. They may protect against pathogens by means of competitive inhibition (i.e., by competing for growth/dispalcement) and there is evidence to suggest that they may improve immune function by increasing the number of IgA-producing plasma cells, increasing or improving phagocytosis as well as increasing the proportion of T lymphocytes and Natural Killer cells. Clinical trials have demonstrated that probiotics may decrease the incidence of respiratory tract infections and dental caries, LAB foods and supplements have been shown to be effective in the treatment and prevention of acute diarrhea; decreasing the severity and duration of rotavirus infections in subjects as well as travelers diarrhea.
Helicobacter pylori
LAB are also thought to aid in the treatment of Helicobacter pylori infections (Antibiotic associated diarrhea). A meta-analysis suggested probiotics may reduce antibiotic associated diarrhea.
Reducing Inflammation
LAB foods and supplements have been found to modulate inflammatory and hypersensitivity responses, an observation thought to be at least in part due to the regulation of cytokine function. Clinical studies suggest that they can prevent reoccurrences of inflammatory bowel disease and decrease the risk of atopic eczema.
Improving Mineral Absorption
It is hypothesized that probiotic lactobacilli may help correct malabsorption of trace minerals, found particularly in those with diets high in phytate content from whole grains.
Prevents Harmful Bacterial Growth Under Stress
In a study done to see the effects of stress on intestinal flora, rats that were fed probiotics had little occurrence of harmful bacteria latched onto their intestines compared to rats that were fed sterile water.
Irritable Bowel Syndrome and Colitis
B. infantis 35624, found to improve some symptoms of irritable bowel syndrome Another probiotic bacterium, Lactobacillus plantarum 299V, was also found to be effective in reducing IBS symptoms Additionally, a probiotic formulation, VSL3, was found to be effective in treating ulcerative colitis, Bifidobacterium animalis DN-173 010 may help.
Synbiotic
It is also possible to increase and maintain a healthy bacterial gut flora by increasing the amounts of prebiotics in the diet such as inulin, compound As probiotics are mainly active in the small intestine and prebiotics are only effective in the large intestine, the combination of the two may give a synergistic effect. Appropriate combinations of pre-and probiotics are synbiotics.
Synbiotics have also been defined as metabolites produced by ecoorgan or by synergistic action of prebiotics and probiotics e.g. short chain fatty acids, other fatty acids, amino acids, peptides, polyamines, carbohydrates, vitamins, numerous antioxidants and phytosterols, growth factors, coagulation factors, various signal molecules such as cytokine-like bacteriokines.