Disturbance of Intestinal Flora (Dysbiosis): Microbiological Therapy

By means of microbiological therapy – also called symbiosis control – the bacterial balance in the intestine is restored (intestinal rehabilitation) and a healthy intestinal environment is established. This is done by administering probiotics. For the term probiotics (Greek: pro bios – for life) there are currently different definitions. According to the definition by Fuller 1989, a probiotic is “a preparation of living microorganisms which, after oral administration, influences the ratio of intestinal germs (intestinal bacteria) in such a way that positive effects on the organism result”. At the European level, the following characterization emerged from a meeting of experts in Brussels on the subject of probiotics in the fall of 1995: “Probiotics are living, defined microorganisms which, after their consumption, exert health-promoting effects that go beyond the level of the basic nutritional-physiological effects. They may be ingested as a food ingredient or in the form of a non-food preparation.” In both definitions, the goal of a probiotic is clear, namely to influence the existing intestinal flora in a way that both enhances well-being and promotes health. The human intestine harbors more than 10 to the power of 14 microorganisms. While the intestinum tenue has a relatively low bacterial colonization – it increases from the duodenum (small intestine) and jejunum (one of the three sections of the small intestine) to the ileum (scimitar; part of the small intestine that follows the jejunum) – the colon (large intestine) is the intestinal section with the highest bacterial colonization density. The microorganisms of the colon can be assigned 400 different species. Due to the fact that the composition of the intestinal flora is subject to individual fluctuations, about 40 species can be detected regularly. Among the quantitatively most important species are Bacteroides, Eubacterium and Bifidobacterium. The dry mass of the stool consists of 30-75% bacteria. Probiotics contain living microorganisms that exert desirable effects on the intestine. In principle, probiotic germs can come from various sources. However, it has been proven that such bacterial strains originally isolated from the human or animal intestine are particularly stable. Due to their origin, they are very well adapted to the milieu conditions in the intestine. Selected lactic acid bacteria, mainly of the genus Lactobacillus and Bifidobacterium, are used as probiotics. Lactic acid bacteria used as probiotics in foods. Lactobacilli

  • L. acidophilus
  • L. casei
  • L. crispatus
  • L. delbrueckii subspecies bulgaricus
  • L. delbrueckii subspecies lactis
  • L. gasseri
  • L. helveticus
  • L. johnsonii
  • L. lactis
  • L. paracasei
  • L. plantarum
  • L. reuteri
  • L. rhamnosus
  • L. salivarius

Bifidobacteria

  • B. adolescentis
  • B. animalis
  • B. bifidum
  • B. breve
  • B. infantis
  • B. longum

Other

  • Enterococcus faecalis
  • Enterococcus faecium
  • Lactococcus lactis
  • Streptococcus thermophilus
  • Saccharomyces boulardii
  • Sporolactobacillus inulinus
  • Bacillus cereus toyoi
  • Escherichia coli

Probiotics can be ingested as a component of a food or as a non-food preparation. Most probiotic foods are used in fermented dairy products. Yogurt and yogurt-like products are the most common fermented dairy products consumed in our country. These naturally contain live lactic acid bacteria, primarily lactobacilli and bifidobacteria. Probiotic yogurts are produced according to legal regulations by fermentation with Lactobacillus bulgaricus and Streptococcus thermophilus. Both germs mutually favor their growth. Following the fermentation processes, other probiotic bacterial strains can be added to the yogurt. In addition to probiotic butter, cheese and curd preparations, probiotic microorganism cultures are also added to other foods. These include baked goods and confectionery, ice cream, breakfast cereals and mueslis, and non-dairy foods such as raw sausages.The influence of fermented meat products, for example raw sausage and vegetables such as sauerkraut and kimchi – lactic fermented vegetables, mainly Chinese cabbage, regularly consumed in Korea – on the human organism has been little studied. Based on common experience, fermented dairy products were known to be a means to long life as early as the end of the 19th century. It is said that “yahurt” – nowadays yogurt – is the secret of people over 100 years old in the Balkans. Moreover, yogurt was used for treatment and prophylaxis of gastrointestinal infectious diseases, for example, diarrheal diseases. The Russian bacteriologist Ilya Metschnikov was the first to investigate the effect of probiotic microorganisms on the human organism using the methods of the time. He was able to show that probiotic germs pass through the digestive tract alive and are excreted in the stool. He assumed that lactic acid bacteria ingested with fermented milk promote health and counteract the process of aging. The prophylactic or therapeutic effect in the intestinal tract of orally ingested microorganisms is subject to various basic conditions. Accordingly, a probiotic bacterial strain should meet the following requirements to be effective.

  • Health safety of probiotic germs. No pathogenic (disease-causing) or toxic (poisonous) effects may emanate from their consumption; probiotic cultures therefore have GRAS status – generally recognized as safe.
  • Resistance to gastric and bile acids and various digestive enzymes. The probiotic bacterial strains must be able to pass both the stomach – acidic pH due to gastric acid and pepsin as a protein-cleaving enzyme – and the upper small intestine – high concentrations of bile salts and protein-cleaving enzymes from the pancreas without accepting damage.
  • Anaerobicity or microaerophilicity – the probiotic organism should be adapted to the low-oxygen conditions in the intestine.
  • Adhesive capacity to the enterocytes of the intestine as a prerequisite for temporary or permanent colonization of the surface of the intestinal mucosa or intestinal tract. For this purpose, the lactic acid bacteria synthesize special proteins and polysaccharides as adhesion factors.
  • Creating ecological niches for their growth. By expressing organic acids, especially lactic acid, and bacteriocins – proteins and low-molecular peptides – the probiotic Lactobacilli and Bifidobacteria can displace existing groups of germs, such as Clostridia, Bacteroides and E. Coli, displace them. In this way, a temporary colonization of the intestine with probiotic bacteria is ensured. Additional administration of prebiotics can promote colonization of the intestine. Prebiotics are non-digestible food components, such as resistant starch and non-starch polysaccharides or dietary fibers, such as oligofructose or inulin. They serve as a selective nutritional basis for probiotic bacteria and intestinal flora (intestinal flora) and thus specifically stimulate the growth and/or activity of individual or a limited number of positive bacterial strains in the colon. Thus, potentially microorganisms with a health-promoting influence for humans can accumulate in the colon.
  • Necessary minimum bacterial count. Since the probiotic effect is dose-dependent, for example, due to the individual constitution of the consumer, type of bacterium – strain specificity – or food composition, and despite the high resistance to the digestive secretions usually only about 10-30% of the consumed probiotic microorganisms reach the colon vital, at least 106 live germs per g of food product are required.
  • Intake of live probiotic cultures in the diet or as a non-food preparation should be daily to maintain high concentrations of replicable germs in the colon. Only a regular supply of the probiotic microorganisms can provide health benefits. Since probiotic lactobacilli and bifidobacteria can not permanently colonize the intestine, if the oral supply is interrupted, the introduced germs are displaced again after a short time and their number in the feces is reduced.
  • Technological suitability.The survivability of probiotic organisms should be guaranteed under the environmental conditions of the food with which they are administered, both before and after fermentation and for the entire period of the declared minimum shelf life in sufficiently high numbers of germs while preserving the probiotic effect.
  • Probiotics must be clearly defined in their properties.
  • No ability to degrade mucins – organic mucins from the group of glycoproteins -, hemagglutination and formation of biogenic amines.
  • Demonstrate the postulated health effects for each bacterial culture in the form of appropriate clinical studies in humans. It is important to know that the probiotic effects depend on the particular strain of bacteria (strain specificity). Even closely related bacterial species of the same species may show differences in their physiological effects. Furthermore, the probiotic properties also depend on the type, composition and physical structure of the food consumed.
  • Laboratory investigation of important physiological parameters, such as the activity of the lactose-cleaving enzyme beta-galactosidase (lactase), intestinal survival, and in vivo macrophage stimulation.

As far as the microorganisms used should not also provide fermentation services, they should not or not significantly affect the sensory properties of the food.

Functions

After consumption of probiotic foods, the bacterial strains enter and colonize the colon. They have the ability to proliferate and exert various health-related effects. With the experimental and clinical studies currently available, it can be demonstrated that probiotics are capable of the following beneficial effects.

  • Promotion or maintenance of optimal intestinal flora.
  • Prevention of colonization of pathogenic germs in the intestine and the passage of pathogenic bacteria through the intestinal wall (translocation).
  • Strengthening immunological defense mechanisms including immunomodulation and stimulation – constant training of natural immune defenses, that is, stimulation of antibody formation and production of macrophages.
  • Prevention of intestinal and vaginal infections intestinal and vaginal infections).
  • Reduced frequency, shortening of duration and reduction in severity of various diarrheal diseases.
  • Improvement in symptoms of irritable colon (irritable bowel syndrome).
  • Increase motility of the intestine, relieve constipation (constipation) and flatulence (flatulence).
  • Reduction in the risk of allergies and autoimmune diseases.
  • Inhibition of carcinogenesis in the colon (cancer formation in the large intestine).
  • Lowering cholesterol levels – avoiding hypercholesterolemia -, influencing lipid metabolism.
  • Alleviation of symptoms of lactose intolerance (lactose intolerance) and improvement of lactose digestion in malabsorption.
  • Delay the aging process
  • Prevention and treatment of diverticulosis (diverticular disease) and diverticulitis (inflammation of the wall of the diverticulum).
  • Positive influence on radiation therapies.
  • Protection against atopic dermatitis (neurodermatitis)
  • Potential effect in hepatic encephalopathy (disorder of brain function that develops as a result of liver failure) and renal insufficiency (kidney weakness).
  • Biosynthesis of vitamins such as vitamin B12, vitamin B6 (biotin) or vitamin K1.
  • Increase mineral absorption, especially calcium.
  • Osteoporosis prevention (prevention of bone loss).
  • Metabolism of xenobiotics (chemical compounds that are foreign to the biological cycle of an organism or natural ecosystems).

In addition to the protective effects on health, probiotic lactic acid bacteria also guarantee the shelf life of the fermented food. The acids formed during fermentation by the bacteria and other microbial inhibitors have a growth inhibiting effect on undesirable germs.

Promotion or maintenance of optimal intestinal flora

Probiotic microorganism cultures are able to influence the composition of the natural intestinal flora.The focus is on lactobacilli and bifidobacteria, which displace potentially harmful groups of germs from binding sites in the intestinal epithelium by forming organic acids – lactic acid, acetic acid, short-chain fatty acids – and bacteriocins – proteins and low-molecular peptides. In this way, they make it difficult for pathogenic microorganisms to adhere to the intestinal mucosa and hinder their settlement in the intestinal tract. Thus, lactobacilli and bifidobacteria exhibit antibacterial and antimicrobial effects, respectively. Bifidobacteria, in contrast to lactobacilli, can express acetic acid in addition to lactic acid and short-chain fatty acids. These organic acids lower the pH in the intestine. On the one hand, this leads to increased growth of desirable microorganisms and, on the other, to a significant reduction in the number of various pathogenic germ species, such as Fusobacteria, Clostridia, Bacteroides and E. Coli. In addition, bifidobacteria are believed to be able to inhibit the growth of pathogenic bacteria. Among the lactobacilli, the species Lactobacillus reuteri in particular has the ability to exert antimicrobial activity on intestinal bacteria and fungi as well as protozoa. By competing with the aforementioned microorganisms for nutrients and growth factors, the probiotic L. reuteri impair the pathogenic bacteria, fungi and protozoa in their development and reproduction. Furthermore, the antimicrobial effect of probiotic cultures is based on the synthesis of hydrogen peroxide. This reacts with thiocyanate, which is produced as a metabolic intermediate in the intestine or comes from food. Subsequently, under the influence of the milk-derived enzyme lactoperoxidase, various oxidation products are formed, which are believed to have antimicrobial effects. Finally, with the help of probiotic microorganisms, the balance in the intestine is maintained or restored and a healthy intestinal environment is established.

Immunomodulatory effect

The intestine is the largest immune organ of the human body. The so-called M cells (components of the so-called follicle-associated epithelium (FAE) covering the Peyer’s plaques) of the intestinal mucosa are part of the immunological barrier and allow constant contact of the intestinal contents with the gut-associated lymphoid tissue – gut-associated lymphoid tissue, GALT. The GALT plays an essential role in the maintenance of immunological functions. Via M cells, it can recognize potentially pathogenic macromolecules and microorganisms in the intestinal lumen and thus trigger specific immune responses. By rebalancing increased permeability of the intestinal mucosa (intestinal mucosa) on the one hand and optimizing the immunological barrier on the other, probiotic microorganism cultures strengthen the barrier function of the intestinal mucosa. The risk of developing autoimmune diseases can thus be limited. With the use of probiotics, immunomodulatory effects can also be achieved outside the intestine. Since probiotic cultures promote the functions of the intestine-associated immune system, certain mucous membranes, such as the bronchial mucosa, are influenced in a positive sense via the GALT. Based on experimental findings, the supply of lactic acid bacteria influences the release of cytokines. Cytokines are also called mediators, as they regulate the function of the cells of the immune system. There are four main groups of cytokines.

  • Interferons – with immunostimulatory, especially antiviral and antitumor effects.
  • Interleukins – serve among themselves to communicate the immune defense cells (leukocytes) to fight coordinated pathogens or even tumor cells.
  • Colony-stimulating factors – growth factors of erythrocytes and leukocytes, for example, erythropoietin (synonyms: EPO, erythropoietin).
  • Tumor necrosis factors – endogenous messengers of the cells of the immune system; tumor necrosis factor-alpha – TNF-alpha, cachectin – acts on inflammation, erythropoiesis, immune defense, angiogenesis and tumors; tumor necrosis factor-beta -TNF-beta, lymphotoxin – activates macrophages, which subsequently release interleukin-1, interleukin-6 and TNF-alpha.

Finally, probiotics contribute to the improvement of humoral – concentration of immunoglobulins, interferons and interleukins – and cell-mediated – activity of macrophages and B cells – immunological defenses by stimulating cytokine release. The probiotic microorganisms affect, among others, proliferation of tumor cells, multiplication of viruses, activation of macrophages, inflammatory reactions, and antibody formation. The special importance of secretory immunoglobulin A (IgA) antibodies was demonstrated in a study. Healthy subjects were given fermented milk containing Bifidobacteria and Lactobacillus acidophilus and an attenuated strain of Salmonella typhi. The result was a more than several-fold higher concentration of specific serum IgA against Salmonella typhi. In another study, Lactobacillus acidophilus was shown to increase both macrophage activity and gamma interferon synthesis in lymphocytes. Macrophages represent scavenger cells of the immune system that take up pathogens by phagocytosis and destroy them intracellularly. The use of probiotics can improve the immune response to oral poliomyelitis vaccination. Poliomyelitis is an infectious disease caused by polioviruses that can affect the muscle-controlling nerve cells of the spinal cord in the unvaccinated and cause permanent paralysis and even death. Probiotic lactobacilli should be administered daily for at least 5 weeks prior to poliomyelitis vaccination to achieve significant effects. They lead to the increase of the following parameters.

  • Activity of virus-neutralizing antibodies.
  • Serum concentration of poliospecific IgG.
  • Local immunity of the intestinal mucosa by increasing the concentration of IgA.

Allergic rhinitis (hay fever)

Probiotic use reduces nasal symptoms of allergic rhinitis and thus may lead to a reduction in medication. Disease-related quality of life increases.

Anticarcinogenic effect

It is considered certain that oral intake of certain strains of Lactobacillus acidophilus and casei is associated with a reduction of bacterially synthesized enzymes via a change in the microbial spectrum in the colon. We are talking about beta-glucoronidase, nitroreductase and azoreductase. These enzymes activate precursors and inactivated forms of carcinogens, respectively, and thus promote the formation of atypical adenomas. The latter are often precursors of colorectal carcinoma. Also, administration of Bifidobacterium bifidum and Lactobacillus GG resulted in a decrease in the concentrations of beta-glucuronidase, nitroreductase, and azoreductase in intestinal contents and feces in human and animal studies. In addition, the probiotic effect of lactic acid bacteria inhibits the activity of 7-alpha-dehydroxylase synthesized by colon bacteria. This enzyme converts primary into secondary bile acids. The latter increase cell proliferation in the colon mucosa, leading to uncontrolled cell growth and thus promoting the development of colon carcinoma. The mechanism of inhibition of 7-alpha-dehydroxylase is based on the acidifying properties of probiotic microorganisms. The expressed lactic and acetic acids and short-chain fatty acids lower the pH in the colon. Since 7-alpha-dehydroxylase is only active at a pH of 7.0-7.5, the now acidic pH leads to a decrease in activity of the enzyme. The formation of carcinogenic secondary bile acids is thus prevented. A reduction in the activities of beta-glucuronidase, nitroreductase, azoreductase and 7-alpha-dehydroxylase in intestinal contents and feces was observed not only with the ingestion of fermented milk, but also after prolonged regular consumption of sauerkraut and kimchi – lactic acid-fermented vegetables, predominantly Chinese cabbage, regularly consumed in Korea. When protein-rich foods are heated, heterocyclic amines are formed that can have mutagenic (stimulation of mutations in the genetic material) or carcinogenic (cancer-forming) effects.Some strains of lactobacilli are able to bind these amines and render them harmless. Furthermore, lactobacilli can degrade N-nitroso compounds, which are carcinogenic and are formed from nitrites and amines during the frying and smoking of food or in the human stomach. Animal studies confirmed that lactic acid-producing bacteria are able to inhibit tumorigenesis and tumor growth in rats. Rats were administered the probiotically active Bifidobacterium longum and at the same time the carcinogenic 2-amino-3-methylimidazole [4,5-f]-quinoline, which is produced by heating meat and fish. By promoting the degradation of this carcinogenic pyrolysis product, Bifidobacterium longum, the probiotic bacterial strain greatly reduces tumor rates. Animal and clinical studies support that probiotic lactic acid bacteria counteract carcinogenesis in the intestine by the following criteria.

  • Nonspecific stimulation of the immune system
  • Enhancement of cellular immunity
  • Reduced formation of carcinogenic substances in the intestine
  • Synthesis of antimutagenic and anticarcinogenic substances through quantitative and qualitative changes in intestinal flora.
  • Inhibition of tumor cell division and tumor growth by glycopeptides and metabolites of lactobacilli.
  • Reduction of the genetic modification effect of the intestinal contents.
  • Reduction of DNA damage already induced.

The risk of extratestinal carcinogenesis is also significantly reduced by regular use of probiotic lactobacilli. The results of numerous studies made it clear that in healthy subjects who consumed roasted beef and also fermented milk with Lactobacillus casei, the mutagenicity of urine decreased. In addition, probiotic intake reduced the recurrence rate of superficial bladder carcinoma.

Atopic Eczema (Neurodermatitis)

Administration of probiotic bacteria was able to reduce the incidence of atopic eczema by half in newborns. In this study, both the mothers before birth and the newborns received the probiotic bacterial strain Lactobacillus GG until six months after birth. A later follow-up of the study participants showed a persistence of this protective effect. Administration of probiotics significantly improves the SCORAD in children with atopic dermatitis. The SCORAD (Scoring Atopic Dermatitis) is used to quantify the extent and intensity of atopic eczema. Probiotics are also used in the treatment of atopic eczema in adults.

Diverticulosis, diverticulitis

Diverticulosis is a change in the colon in the form of small diverticula of the entire intestinal wall and is usually completely asymptomatic. Diverticulitis, on the other hand, is a disease of the colon in which inflammation forms in the diverticula of the intestinal mucosa. Various bacterial strains have been shown to be effective in both prevention and therapy of diverticulosis and diverticulitis. Therefore, this type of therapy will assume a greater role in the future than it has in the past.

Intestinal and vaginal infections

Fermented dairy products or the lactic acid bacteria they contain are considered important in the prevention or treatment of intestinal infections. This concerns viral, bacterial as well as fungal infections. In prospective studies, the administration of fermented milk resulted in a lower incidence of gastroenteritis caused by rotaviruses in children. If infection had already occurred, the probiotic germs reduced the frequency of defecation as well as the excretion of the viruses in the stool. Rotaviruses are the most common cause of severe diarrhea. The therapeutic effect of probiotics has also been noted in diarrhea of other etiologies (causes), such as diarrhea caused by radiation and antibiotic therapy. According to a multicenter study, rehydration solutions with an addition of Lactobacillus GG resulted in faster recovery in children with severely watery diarrhea. Furthermore, there are reports on the positive influence of lactobacilli in diarrhea caused by Clostridium difficile – an anaerobic, gram-positive rod bacterium – as a result of antibiotic treatment.Also of practical-clinical interest is the protection of probiotic cultures against colonization of the gastric mucosa with Helicobacter pylori, a Gram-negative, microaerophilic bacterium. In a study of 138 patients, it was shown that administration of probiotic yogurt containing lactobacilli and bifidobacteria improved the eradication rate of Helicobacter pylori in combination with antibiotic therapy. Thus, probiotics play an important role in the prevention and treatment of gastritis. The use of lactic acid bacteria in the treatment of vaginal mycosis (vaginal fungus) proved to be quite successful. Under controlled experimental conditions, women with recurrent candidavulvovaginitis consumed yogurt containing Lactobacillus acidophilus daily for a period of 6 months. The antimicrobial effect of Lactobacillus was evident by a significant decrease in clinical symptoms and a reduction in colonization by the fungus Candida albicans. In addition, probiotic germs also protect the rectum and mucous membranes from Candida albicans infestation. The administration of lactobacilli can significantly reduce the recurrence rate (recurrence of the disease) of bacterial vaginosis by about 50%. Furthermore, it significantly improves a severely disturbed flora (vaginal microbiota). By improving the intestinal immune system, normalizing the intestinal flora and inhibiting inflammatory tissue reactions, probiotics can positively influence the disease course of both chronic inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis, and extraintestinal diseases, such as rheumatoid arthritis and allergies. The cause of inflammatory and allergic reactions is considered to be the misregulation of the immune response to the antigenic structure of intestinal microorganisms. Patients with chronic inflammatory bowel disease or extraintestinal diseases therefore exhibit an incorrect composition of their intestinal flora, as a result of which the tolerance of the intestinal microorganisms is apparently disturbed. Healthy people, on the other hand, tolerate their intestinal flora. In ulcerative colitis patients, treatment with the E. coli strain Nissle led to a significant decrease in disease symptoms within 12 months. In addition to intestinal and vaginal infections, probiotic organisms also play a role in urogenital infections. Several reports suggest that regular probiotic intake reduced the recurrence of cystitis.

Irritable colon (irritable bowel syndrome)

Irritable colon is the irritable bowel syndrome associated with symptoms originating in the small and large intestine. In the majority of cases, certain symptoms are prominent. These include constipation, diarrhea, and flatulence associated with pain. Irritable colon is a factor disease, meaning that the condition can be triggered by several factors. Several lines of evidence suggest that peculiarities in the composition of the intestinal flora are involved in the development of irritable colon. Therapeutic studies have tested the effect of probiotics on patients with irritable bowel syndrome, with extremely positive results. The fermented foods, most of which contained Lactobacillus plantarum, restored intestinal balance in the patients and led to the establishment of healthy intestinal flora. This resulted in a significant decrease in both abdominal pain and flatulence. In a study of 77 participants with irritable bowel syndrome, treatment with Bifidobacterium infantis normalized the ratio of anti-inflammatory to pro-inflammatory signaling substances and improved symptoms.

Reduction of serum cholesterol levels

The cholesterol-lowering effect of probiotic lactic acid bacteria is based on the observation that men from the Masai tribe in Africa drink 4-5 liters of fermented milk daily and have exceedingly low serum cholesterol levels. In particular, fermented milk and milk enriched with Lactobacillus acidophilus led to a decrease in serum cholesterol in some studies. However, studies also exist that failed to demonstrate a relationship between probiotics and serum cholesterol levels. For example, a number of targeted studies with yogurt, predominantly prepared using Lactobacillus acidophilus, yielded inconsistent results.A possible mechanism of action under discussion is an inhibitory effect of probiotics on the enzyme 3-hydroxy-3-methyl-glutaryl-CoA reductase – HMG-CoA reductase. In the liver, HMG-CoA reductase converts HMG-CoA, which is formed by the breakdown of free fatty acids, to cholesterol. Due to the enzyme inhibition, endogenous cholesterol synthesis is ultimately restricted and serum cholesterol levels are lowered. Furthermore, it is believed that probiotic lactic acid bacteria can deconjugate conjugated bile acids, resulting in less bile acids being reabsorbed. The result is an increased de novo synthesis of bile acids. Endogenous cholesterol is increasingly used for their regeneration, resulting in a reduction of serum cholesterol levels. In addition to the effect of probiotics on endogenous cholesterol, the influence on exogenous cholesterol is probably also decisive for the cholesterol-lowering effect. It is assumed that probiotic cultures can directly degrade dietary cholesterol.

Potential effect in hepatic encephalopathy and renal insufficiency

Patients with hepatic encephalopathy and renal insufficiency (kidney weakness), respectively, suffer from liver and kidney dysfunction. By reducing toxic protein breakdown products and decreasing absorption of ammonia (NH3) due to a decrease in intestinal pH, probiotics can help prevent these conditions or alleviate symptoms in those with existing disease.

Lactose Intolerance

Individuals with lactose intolerance (milk sugar intolerance) are unable or only partially able to break down lactose (milk sugar) ingested through food. Poor lactose digestion is due to a lack of or reduced production of the enzyme beta-galactosidase, also known as lactase. In the small intestine, lactase breaks down milk sugar into the sugars glucose and galactose, which are usable by humans. If uncleaved lactose reaches the large intestine, it is fermented by intestinal bacteria. The fermentation products lead to flatulence, meteorism, a feeling of pressure and diarrhea after a time lag following the consumption of milk or dairy products. Consumption of fermented dairy products is comparatively well tolerated by lactase deficiency syndrome patients. The reason for this is the high number of live lactic acid bacteria that contain the lactose-cleaving enzyme beta-galactosidase. This is firmly enclosed in the bacterial cell and, supported by the buffering capacity of the milk, can pass through the stomach unharmed – it is rapidly inactivated at a pH of less than 3. Due to the high bile salt concentration in the upper small intestine, the permeability of the bacterial cell membrane is presumably increased, promoting the release of lactase into the intestinal lumen. As a result, increased lactose degradation occurs. Crucial for the release of beta-galactosidase from bacterial cells is the structure of the cell wall, which differs from bacterium to bacterium. When comparing Lactobacillus acidophilus and Lactobacillus bulgaricus with the same lactase activity inside the cell, it was found that the intake of probiotic dairy products containing mainly L. bulgaricus resulted in significantly higher lactose tolerance in patients. This is due to the specific wall structure of this bacterial species, which allows increased lactase secretion and thus increased lactose cleavage in the intestinal lumen. Since different bacterial strains and species are used in the production of fermented milk products, lactose tolerance varies depending on the product consumed. Heat-treated fermented milk products have a less pronounced effect on lactose intolerance. Therefore, patients should be careful to select only those dairy products with live germs.

Radiotherapy (Radiotherapy, Radiatio)

It was found that patients after pelvic radiatio suffered less diarrhea (diarrhea) if they ingested lactic acid-producing bacteria. In addition, consumption of fermented dairy products reduced the extent of late effects of radiotherapy.

Delaying the aging process

Scientific findings increasingly demonstrate the importance of intestinal microorganisms for functions of the human organism.Of particular interest is the influence of the intestinal flora on the aging process. With increasing age, the number of bifidobacteria decreases and that of Clostridium perfringens decreases. This leads to increased putrescence – bacterial protein degradation – in the colon and thus to the formation of toxic degradation products. It is possible that these toxic degradation products are involved in the aging process. As early as the end of the 19th century, the Russian bacteriologist Ilya Metschnikov saw a link between probiotic microorganisms and aging. Since probiotics are able to modify the intestinal flora in favor of bifidobacteria, putrescence in the colon is reduced. Thus, regular intake of probiotic lactic acid bacteria could delay the aging process.