11-Microbiome-1

Introduction to the Microbiome

• Presenter: Michael Helser, Ph.D.

• Course: NUTR&101

The Microbiome Community

• Unique communities live on and in humans:

  • Skin, mouth, intestines, vagina

  • Composed of trillions of microbes

Benefits of Microbes

• Provide various benefits to human health:

  • Aids in carbohydrate digestion and energy production

  • Supports the immune system

• Risks involved if the balance of bacteria is disrupted:

  • Can lead to health problems

Development of the Microbiome

Birth and Initial Exposure

• Microbiome begins to develop at birth:

  • Vaginal births expose infants to maternal microbes

  • Differences based on home vs. hospital births and breastfeeding vs. formula feeding

Environmental and Lifestyle Influences

• The microbiome is influenced by:

  • Environmental exposure (urban vs. rural living)

  • Diet (plant vs. animal-based food)

  • Health (illnesses experience)

  • Medications (especially antibiotics)

Oral Microbiome

• Microbes found in:

  • Teeth, tongue, gums, tonsils

  • Mostly harmless, but changes with:

    • Diet, hygiene, and lifestyle (e.g., smoking)

Factors Affecting Gut Microbiota

Response to Dietary Changes

• Microbiota changes in response to:

  • Diet (carbohydrates, fiber, and types of food)

  • Malnutrition and diseases

  • Medications like broad-spectrum antibiotics

Environmental Impacts

• Factors affecting microbiome include:

  • Air pollution (affects lipid metabolism)

  • Antibiotics (impact on stress response)

  • Artificial sweeteners (linked to weight gain)

  • Birth mode (influences offspring metabolism)

  • Chronic stress (linked to conditions like colitis)

  • Diet (contributes to obesity)

  • Exposure to chemicals (flame retardants, heavy metals)

Human Microbiota Profile

• Composition includes:

  • Bacteria, viruses, and eukaryotes (fungi, yeast)

  • Typical weight of microorganisms: 4-6 pounds per person

  • Microbial and human cells are in similar quantities

• Roles in:

  • Digestion

  • Immune function

Microbiome Composition in GI Tract

Microbial Distribution

• Concentrations of microbes noted in various GI tract regions:

  • Stomach and Duodenum: 101-102 CFU/mL (e.g., Lactobacilli, Streptococci)

  • Colon: 1010-1012 CFU/mL (e.g., Bacteroides, Bifidobacteria)

  • Jejunum and Ileum: 104-108 CFU/mL (e.g., Lactobacilli, Bacteroides)

Identifying Microbe Types: 16S rRNA

• Uses 16S rRNA sequence markers to distinguish microbial types:

  • Constant regions help identify known bacteria

  • Hyper-variable regions provide specific microbial identities

  • Analyzing mixed samples reveals presence of particular bacteria

Microbiome Development through Delivery Method

• Impact of delivery modes on microbiome:

  • Vaginal delivery introduces beneficial bacteria (Lactobacillus)

  • C-section delivery links to higher risks of allergies and autoimmune diseases

Childhood Diseases Linked to Cesarean Delivery

Associated Health Risks

• Increased odds ratio for:

  • Allergic Rhinitis, Asthma

  • Celiac Disease, Diabetes Mellitus (Type 1), Gastroenteritis

Importance of Breastfeeding

Benefits of Breast Milk

• Contains beneficial bacteria and oligosaccharides:

  • Supports respiratory and gastrointestinal health

  • Trains the baby's immune system

Role of Microbes in Digestion

• Microbes provide:

  • 6-10% of energy intake

  • Essential vitamins and hormones for appetite regulation

  • Protection against pathogens

• Produce short chain fatty acids (SCFAs):

  • Nutritional support for intestinal cells and anti-inflammatory effects

Dietary Influence on Gut Microbiota

Study Overview:

• Examined gut microbiota changes in children from Burkina Faso vs. Italy:

  • Traditional diets (high in fiber) vs. Westernized diets (high in fat and sugar)

  • Resulted in competition among different bacterial genera affecting diversity

Characteristic Differences in Microbiomes

Assessing SCFA Levels

• SCFA levels differ among populations:

  • Rural children's microbiota retain unique fiber-degrading bacteria

  • Urban children have different profiles, often favoring protein-rich and sugary foods

Biodiversity of Microbiome and Obesity

Connection to Body Weight

• Increased Firmicutes and decreased Bacteroidetes can correlate with obesity:

  • Studies show variation in percentages of these taxa associated with dietary differences

Microbiota Fecal Transplantation

• A potential therapy for re-establishing healthy gut microbiota, particularly post-antibiotic use to treat C. difficile infections.

Distinction Between Probiotics and Prebiotics

• Probiotics: Live beneficial microorganisms.

• Prebiotics: Nutrients that support these microorganisms.

Maintaining Microbiome Health

Recommendations

• Interact with pets and farm animals

• Avoid excessive use of antibacterial products

• Engage in outdoor activities

• Incorporate diverse, fiber-rich fruits and vegetables into diet.