Human Composition: Only a small percentage of what makes us human is actually human. We are composed of about 10 parts microbes and 1 part human.
Unique Genes: In terms of unique genes, we are only 1% human.
Microbial Dependency: Humans and microbes have co-evolved; we need each other for health.
The Human Microbiome
Definition: A set of microbial communities that live in and on our bodies.
Functions Provided by Microbiome:
Help digest complex polysaccharides from plants.
Offer protection against harmful microbes (competitive exclusion or colonization resistance).
Assist in nutrient recycling and cholesterol management.
Microbial Distribution
Location: Microbes are found in various parts of the body, with the highest concentration in the bowel.
Mouth: Approximately 10 million microbes per gram.
Colon: About 100,000 times more microbes than in the mouth.
Effects of Antibiotics
Microbiome Damage: Antibiotics can severely impact our microbial communities, decimating them more than previously understood.
Health Implications:
Healthy individuals may recover from occasional antibiotic use, but sick individuals face greater risks and difficulties.
Potential risk of Clostridium difficile infections after antibiotic use, which can lead to significant illness and death.
Probiotics as a Solution
Definition: Substances that restore friendly bacteria to the microbiome.
Evidence: Early evidence suggests potential benefits from probiotics, but more research is needed.
Open Questions
Link Between Microbiome and Disease: There is currently no established link between antibiotic damage to the microbiome and diseases such as heart disease and cancer, as this has not been thoroughly investigated.
Conclusion
Shift in Perspective: Instead of viewing bacteria as solely harmful, recognize that 99% of what we are depends on our microbial communities for health and well-being.