Prebiotics and Probiotics Overview

Prebiotics, Probiotics, and Gut Microbiome Modulation

• Prebiotics are non-digestible food components that selectively nourish beneficial gut microorganisms.
• Probiotics are live microorganisms that confer health benefits when administered in adequate amounts.
• Modulation of the gut microbiota can be achieved by dietary approaches or therapeutic interventions.
• Not all dietary interventions or probiotics are universally beneficial.

Therapeutic Strategies

• Prebiotics
• Probiotics
• Synbiotics (combination of prebiotics and probiotics)
• FMT (fecal microbiota transplantation)
• Phage therapy
• miRNA modulation

Probiotic Criteria

• Safety: Human or animal origin, history of safe use, absence of disease association, no adverse effects, no antibiotic resistance genes.
• Functionality: Competitiveness in the gut, ability to survive and metabolise in the gut, resistance to bile salts and enzymes and low pH, antagonistic activity against pathogens.
• Technological Usability: Easy and stable production, high viability and stability during processing and storage.

Probiotic Microorganisms

• Lactobacillus, Bifidobacterium, Lactococcus, Streptococcus, Enterococcus, Bacillus, Saccharomyces, and others.

Mechanisms of Probiotic Beneficial Effects

• Antagonism (production of antimicrobial substances)
• Competition with pathogens
• Immunomodulation
• Positive effects on metabolism
• Inhibition of bacterial toxin production

Probiotics and Inflammatory Bowel Diseases

• Ulcerative colitis: Probiotics can lead to remission.
• Crohn's disease: No positive effect shown.
• Lactose intolerance: Increased lactose digestion and tolerance, reduced diarrhoea.
• Irritable bowel syndrome: Improvements in symptoms (bloating, pain, constipation, cramps, flatulence, potentially).

Probiotics and Cancer

• Animal studies suggest a potential risk reduction, but clinical trials have not confirmed it.
• Probiotics may alleviate gastrointestinal disorders in cancer patients.
• Possible improvements in gut mucosal barrier integrity, reduction in diarrhoea incidence, and less abdominal discomfort.

Probiotics and Diarrhoea & Intestinal Infections

• Saccharomyces boulardii yeast can reduce acute watery diarrhoea frequency.
• Probiotics can be used in nosocomial, non-nosocomial, and viral diarrhoea treatment and may boost IgA antibody production.
• Antibiotics-related diarrhoea (AAD) and Clostridium difficile disease (CDD) show strong responses to probiotics (especially Saccharomyces boulardii).

Probiotics and Extraintestinal Infections

• Probiotics may prevent vaginitis and reduce respiratory tract infections.
• Children with cystic fibrosis may experience reduced pulmonary exacerbations with probiotic administration.
• Probiotics might reduce nosocomial infections (e.g., VAP).

Probiotics and Metabolic Disorders

• Probiotic administration can reduce BMI, arterial BP, and improve lipid profiles and insulin sensitivity in obese individuals.
• Significant reduction in blood glucose, HbA1C, LDL, and total cholesterol in patients with type 2 diabetes.

Probiotics and Atopic Dermatitis (Eczema)

• Probiotic administration to pregnant women and their infants can reduce infant eczema.
• Probiotic treatment can improve AD severity in children with improved IFN-γ and IL-10 ratios.

In Recent Randomized Controlled Trials

• Probiotics may prevent diarrhoea, necrotising enterocolitis, ulcerative colitis, and respiratory tract issues.
• Probiotic treatment could improve cardiometabolic parameters and reduce CRP levels in type 2 diabetes patients.

Prebiotics

• Prebiotics are selectively used to nourish beneficial gut microbial organisms.
• Resistance to digestion in the upper GIT
• Fermentation by gut microbiota
• Beneficial effects on host's health
• Selective stimulation of probiotics growth
• Stability in various food processing conditions

Sources of Prebiotics

• Fruit, vegetables, cereals, and other edible plants.
• Carbohydrates like dietary fibre.
• Prebiotic examples: FOS, GOS, inulin, XOS, lactitol, lactosucrose, lactulose, soy oligosaccharides, and transgalactooligosaccharides.

Fermentable Dietary Fibres

• Inulin, oligofructose, FOS, galactooligosaccharides.
• Increase Bifidobacterium and Lactobacillus in stool samples (and linked to increased SCFAs).

Health Benefits from Prebiotics

• Prevention of carcinogenesis.
• Reduction of blood LDL levels.
• Stimulation of the immunological system.
• Absorbability enhancement of calcium.
• Intestinal pH value maintenance.

Mechanisms of Prebiotic Effects

• Regulation of hepatic enzymes by influencing SCFAs production (e.g., butyric acid).
• Histone acetylation modulation through SCFAs production.
• Modulation of mucin production.
• Increased lymphocyte and/or leukocyte count in association lymphoid tissues.
• IgA secretion enhancement.

Synbiotics

• Combination of prebiotics and probiotics.
• Improvement of probiotic survival in the GI tract.
• Stimulation of native gut bacteria proliferation.
• Increased tolerance of probiotics to environmental factors (oxygenation, pH, temperature).
• Examples: Lactobacillus + inulin, Lactobacillus + FOS, Lactobacillus + oligofructose, Lactobacillus + inulin.

Beneficial Effects of Synbiotics

• Increased counts of Lactobacillus and Bifidobacterium in the gut.
• Improved hepatic function in cirrhosis patients.
• Enhanced immunomodulation.
• Reduced incidence of nosocomial infections (e.g., post-surgical settings).

Clinical Trial Examples

• Synbiotic interventions affect weight, blood glucose, lipid profiles, and insulin resistance.
• Synbiotics may help with IBS, eczema, IBD, and lactose intolerance.
• Specific synbiotics are associated with positive results in certain diseases and conditions.

Metabolites

• Gut microbiota-associated metabolites are crucial in disease development and progression
• Metabolites are used in treating inflammation, metabolic and neurological disorders/diseases, and cancer.
• Advantages: natural bioavailability, high concentrations, easy administration, and tolerable tissue effects

Short-Chain Fatty Acids (SCFAs)

• Exhibit anti-inflammatory effects
• Oral administration alleviates brain inflammation and symptoms associated with multiple sclerosis.
• Colon delivery of SCFAs may counteract psychosocial stress effects.

Other Novel Approaches

• miRNAs: Crucial for homeostasis and have a role in post-transcriptional gene expression regulation.
• Hyaluronan: Unbranched glycosaminoglycan component of the extracellular matrix involved in IBD promotion/resolution.
• Nanomaterials: Possible tools for impacting disease-causing microorganisms and their metabolites in the microenvironment of the cancer.