We are Built by Bacteria
- Madhukar Dama
- 9 hours ago
- 5 min read
Here's a list of 20 unique and mind-blowing facts about the human microbiome that will change the way you see yourself:
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1. You are more microbe than human – Microbial cells in your body outnumber human cells by about 1.3 to 1.
2. Your gut has its own nervous system – Known as the “second brain,” it contains over 100 million neurons, heavily influenced by gut microbes.
3. 90% of serotonin is produced in the gut – Your mood is literally brewed in your intestines by microbes.
4. You host over 100 trillion microorganisms – More than the stars in our galaxy, and each person’s mix is as unique as a fingerprint.
5. Your microbiome can influence who you’re attracted to – Body odors shaped by microbes play a role in mate selection.
6. Microbiome disruptions in infancy can alter your health for life – C-section births and formula feeding reduce microbial diversity.
7. Your gut bacteria can make you fat or thin – Some microbes are more efficient at extracting calories from food.
8. Antibiotics can wipe out your microbiome for months or even years – One round can cause long-term imbalances (dysbiosis).
9. The skin microbiome protects you from invaders – Certain microbes produce natural antibiotics that kill pathogens.
10. Microbes digest what you can’t – Like fibers and complex carbs, turning them into essential nutrients and energy.
11. Your microbiome communicates with your brain through the vagus nerve – Forming a gut-brain superhighway.
12. Each body part has its own unique microbiome – Your mouth, armpits, and belly button host completely different species.
13. Your environment shapes your microbiome – People living with pets, in rural areas, or near soil have more diverse microbiota.
14. Stress alters your microbiome – Anxiety and depression can cause microbial shifts, and vice versa.
15. Microbial genes vastly outnumber human genes – Over 99% of the genes in your body come from microbes, not you.
16. There are viruses that live only to infect your gut bacteria – Called bacteriophages, they’re part of the natural balance.
17. Gut microbes can influence cravings – They signal your brain to eat more of what they want, not what you need.
18. Microbiomes may influence disease more than genetics – In some cases, gut health is a better disease predictor than DNA.
19. The placenta has its own microbiome – Babies are exposed to microbes before they’re even born.
20. Fecal transplants can cure deadly infections – Especially C. difficile, where poop from a healthy person can save a life.
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1. Definition: Natural Microbiome
The natural microbiome refers to the community of trillions of microorganisms—bacteria, viruses, fungi, archaea, and protozoa—that naturally live in and on the human body. These microbes are not harmful; most are beneficial or neutral, playing critical roles in digestion, immunity, metabolism, and more.
2. Classification of Natural Microbiome in the Human Body
Gut (Intestines):
Common microbes: Bacteroides, Firmicutes, Lactobacillus, Bifidobacterium
Functions: Digestion, nutrient synthesis, immune regulation
Skin:
Common microbes: Staphylococcus, Corynebacterium, Propionibacterium
Functions: Protection from pathogens, maintaining skin pH
Mouth:
Common microbes: Streptococcus, Fusobacterium, Veillonella
Functions: Oral immunity, breakdown of food
Nose & Sinuses:
Common microbes: Staphylococcus, Moraxella, Corynebacterium
Functions: Filtering air, respiratory immune modulation
Lungs:
Common microbes: Prevotella, Veillonella, Streptococcus
Functions: Lung immunity regulation, infection prevention
Vagina:
Common microbes: Lactobacillus species
Functions: pH regulation, protection from infections
Urinary Tract:
Common microbes: Lactobacillus, Corynebacterium, Streptococcus
Functions: Urogenital health, preventing pathogen overgrowth
Eyes:
Common microbes: Corynebacterium, Propionibacterium
Functions: Maintaining ocular surface immunity
3. Functions of the Human Microbiome
Digestion & Nutrient Absorption
Breaks down fiber, starches, and proteins
Produces vitamins (B12, K, biotin)
Synthesizes short-chain fatty acids (SCFAs) that nourish colon cells
Immune System Regulation
Trains immune cells to differentiate friend vs foe
Prevents overactive immune responses (autoimmunity, allergies)
Protection Against Pathogens
Competes for space and nutrients
Produces natural antibiotics (bacteriocins)
Metabolic Functions
Regulates fat storage and glucose metabolism
Affects appetite and weight via gut-brain signaling
Brain and Mood Regulation (Gut-Brain Axis)
Produces neurotransmitters like serotonin, dopamine
Influences mood, stress, anxiety, depression
Detoxification
Degrades toxins and carcinogens in the gut
Maintains integrity of the gut barrier (prevents “leaky gut”)
4. Factors That Disturb the Microbiome
Antibiotics and Medications (especially broad-spectrum antibiotics)
Poor Diet (low fiber, high sugar, processed foods)
Chlorinated Water and Pesticides
Stress and Sleep Deprivation
Lack of Natural Birth (C-section) or formula feeding (vs breastfeeding)
Overuse of Sanitizers and Antibacterials
Environmental Pollution
Sedentary Lifestyle
Infections or Chronic Illness
Aging or Hormonal Changes
5. Consequences of Microbiome Disturbance (Dysbiosis)
Digestive Disorders: IBS, bloating, constipation, diarrhea
Autoimmune Diseases: Type 1 diabetes, rheumatoid arthritis, lupus
Allergies and Asthma
Mental Health Disorders: Depression, anxiety, brain fog
Metabolic Syndrome: Obesity, insulin resistance, type 2 diabetes
Skin Issues: Acne, eczema, psoriasis
Increased Infection Risk: Candida overgrowth, C. difficile
Chronic Fatigue and Inflammation
Nutrient Deficiencies
6. Natural Methods to Restore Microbiome
Probiotic-Rich Foods: Yogurt, kefir, sauerkraut, kimchi, miso, kombucha
Prebiotic Foods (fiber-rich): Garlic, onion, bananas, oats, asparagus, flaxseed
Fecal Microbiota Transplant (FMT) – for severe dysbiosis
Herbal Remedies: Triphala, licorice root, turmeric, slippery elm
Organic, Whole Food Diet
Fermented Plant-Based Foods
Breastfeeding (for infants)
Spending Time in Nature: Soil microbes help skin and gut health
Avoiding Unnecessary Antibiotics & Chemicals
Intermittent Fasting: Improves microbial diversity
Stress Management: Meditation, yoga, sleep hygiene
7. Key Studies Showing Microbiome Restoration Reversing Diseases
Borody et al., 2011 (FMT in Ulcerative Colitis): Fecal transplant led to symptom reversal in over 50% of patients.
Turnbaugh et al., 2006 (Microbiome & Obesity): Gut bacteria composition influences fat storage and weight.
Kelly et al., 2014 (FMT in C. difficile Infection): Over 90% cure rate achieved with fecal transplants compared to antibiotics.
Cryan & Dinan, 2012 (Gut-Brain Axis): Specific probiotics improved anxiety and depression symptoms.
Kootte et al., 2017 (FMT in Type 2 Diabetes): Altering the microbiome improved insulin sensitivity.
Kostic et al., 2015 (Autoimmune Diabetes): Changes in the infant gut microbiome preceded type 1 diabetes onset.
Vinderola et al., 2020 (Probiotics & Mood): Probiotic supplementation improved mood and cognitive function in depression patients.
Zuo et al., 2018 (Microbiota & Colorectal Cancer): Altered gut microbiota correlated with tumor regression during treatment.
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the bugs know more than you
you think you’re clean
with your soap,
your cologne,
your hundred-dollar toothpaste.
but a trillion microbes
are laughing their microbial asses off
while they keep you alive
without a thank you.
you kill them
with pills, sprays,
plastic food and pride.
they rebuild
in the gutters of your gut
like broke poets
writing life back into
a rotting town.
your brain?
they built it.
your serotonin?
they brew it like whiskey
in the basement of your bowels.
your immunity?
they are the goddamn border patrol.
you are a hotel
for ancient creatures
and you
don't even comp their stay.
they heal your wounds,
mend your moods,
and still
you call them germs.
the truth?
you’re the guest,
they’re the landlord.
and they
don’t give refunds.