Gut Microbiome and Probiotic Insights

Prebiotics, Probiotics, and Gut Microbiome Modulation

• Prebiotics are indigestible food components that nourish beneficial gut microorganisms.
• Probiotics are live microorganisms that confer health benefits when administered in adequate amounts.
• Modulation of the gut microbiota is possible through dietary approaches and therapeutic interventions.
• There's no universal "magic bullet" diet for healthy microbiota.

Probiotic Selection Criteria

• Probiotics must originate from humans or animals.
• They must be isolated from healthy individuals.
• Historical safety data is essential.
• Accurate and precise identification (phenotype and genotype).
• No association with infectious disease.
• No ability to cleave bile acid salts.
• No adverse effects are present.
• Absence of genes for antibiotic resistance.
• Competitiveness with the existing gut microbiota.
• Resistance to bile, enzymes, and stomach acid.
• Ability to survive and function in the target site (gut).
• Antagonistic activity against pathogens (e.g., H. pylori, Salmonella).
• Resistance to bacteriocins and acids from the gut microbiota.
• Easy production and cultivation methods.
• Preservation of viability during processing and storage.
• Stability of properties during storage.
• Appropriate sensory properties for food applications (as needed).

Probiotic Microorganisms

• Lactobacillus strains (e.g., acidophilus, amylovorus, casei, gasseri, helveticus, johnsonii, etc.)
• Bifidobacterium strains (e.g., adolescentis, animalis, bifidum, breve, infantis, longum, etc.)
• Other lactic acid bacteria (e.g., Enterococcus faecium)
• Other microorganisms (e.g., Bacillus clausii, Saccharomyces cerevisiae)

Mechanisms of Probiotic Beneficial Effects

• Antagonism through the production of antimicrobial substances.
• Competition with pathogens for adhesion and nutrients.
• Immunomodulation of the host.
• Positive effects on metabolism.
• Inhibition of bacterial toxin production.

Probiotics and Inflammatory Bowel Diseases

• Probiotics can lead to remission in ulcerative colitis.
• No significant positive effect on Crohn's disease.
• May improve symptoms of lactose intolerance.
• May improve symptoms of irritable bowel syndrome.

Probiotics and Cancer

• Animal studies suggest probiotics may reduce colorectal cancer risk.
• Human clinical trials are needed to confirm these effects.
• Probiotics may improve gut mucosal integrity and reduce diarrhea in cancer patients.

Probiotics and Diarrheal Infections

• Saccharomyces boulardii can treat acute watery diarrhea.
• Probiotics can reduce antibiotic-associated diarrhea and C. difficile disease.
• Probiotics can increase IgA antibodies, which may stop viruses.

Probiotics and Extraintestinal Infections

• Probiotics may help prevent vaginitis, respiratory infections, and cystic fibrosis exacerbations.
• Probiotics can reduce nosocomial infections (like VAP).

Probiotics and Metabolic Disorders

• Probiotics can reduce BMI, blood pressure, and CRP in obese patients.
• Probiotics may improve lipid profiles and insulin sensitivity.
• Probiotics may reduce blood glucose, HbA1c, LDL, and total cholesterol in patients with type 2 diabetes.

Probiotics and Eczema

• Probiotics given to pregnant women and children can reduce eczema.
• May improve the ratio of IFN-γ and IL-10 in children with eczema.

Probiotics in Recent Trials

• Probiotics reduce diarrhea, necrotizing enterocolitis, ulcerative colitis, acute respiratory infections, and eczema.
• Increase cardiometabolic parameters and potentially reduce CRP in type 2 diabetes.

Prebiotics

• Prebiotics: Non-digestible food ingredients that selectively nourish beneficial gut bacteria.
• Prebiotic selection criteria: Resistance to digestion, fermentation by gut microbiota, beneficial effects on host health, selective stimulation of probiotic growth, stability during food processing.
• Sources: Fruit, vegetables, cereals, other edible plants. Common prebiotics in human nutrition are FOS, GOS, inulin, XOS, lactitol, lactosucrose, lactulose, soy oligosaccharides, and TOS.

Fermentable Dietary Fibers

• Fermentable dietary fibers (like inulin, oligofructose, FOS, and galactooligosaccharides).
• Increase Bifidobacterium and Lactobacillus levels (sometimes associated with higher SCFAs).

Health Benefits of Prebiotics

• Numerous health benefits associated with prebiotic presence.
• Prevention of carcinogenesis, reduction of LDL, stimulation of the immune system, calcium absorbability, and correct intestinal pH maintenance.
• Mechanism of beneficial effects is complex, likely involving SCFA production (especially butyric acid), mucin production modulation, and immune cell regulation.

Synbiotics

• Synbiotics: Combining prebiotics and probiotics.
• Improves probiotic survival and proliferation in the gut.
• Enhances tolerance to gut conditions (e.g., oxygenation, pH, temperature).
• Examples of synbiotic combinations exist.

Synbiotic Benefits

• Increased Lactobacillus and Bifidobacteria.
• Improved hepatic function (in cirrhosis).
• Improved immune response.
• Reduced nosocomial infections (post-surgery).

Clinical Trials of Synbiotics

• Various clinical trials assess synbiotic effects on obesity, type 2 diabetes, insulin resistance, non-alcoholic fatty liver disease, etc., with variable outcomes.

Metabolites

• Gut microbes produce metabolites.
• Key roles in regulating human health and diseases (e.g., inflammation, metabolic disorders, and cancers).
• Some metabolites are therapeutic candidates with excellent properties.

SCFAs and Gut Health

• Short-chain fatty acids (SCFAs) have anti-inflammatory effects.
• Oral SCFAs can alleviate inflammation in the gut-brain axis (e.g., encephalitis, multiple sclerosis).

Other Novel Approaches

• miRNAs: Post-transcriptional gene regulation.
• Hyaluronan: Component of the ECM. Promotion and resolution of IBD.
• Nanomaterials: Modify dysbiotic microorganisms (and metabolites) in the cancer microenvironment.

Explore the fascinating world of prebiotics, probiotics, and gut microbiome modulation. This quiz will assess your understanding of the criteria for selecting effective probiotics and how dietary approaches can influence gut health. Test your knowledge and learn more about the complex interactions within our digestive system.