Scientists studied the skin of a remote Amazonian people and found something that upends modern dermatology: nearly 60% of the bacteria on their skin had never been seen before—and they have almost none of the skin conditions that plague industrialized societies. Here's what the research shows, and why "cleaner is healthier" might be exactly wrong.
Learn Something with Thaena · Published 2025 · Reading time: ~10 minutes
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The Discovery That Rewrites "Healthy Skin"
In 2025, a research team led by Juliana Durack published a study in Nature Communications that challenges the foundations of what dermatology considers a "healthy" skin microbiome. They performed shotgun metagenomic sequencing on 94 skin samples from 17 Yanomami individuals—members of one of the last remaining seminomadic, hunter-gatherer communities in the Amazon rainforest of Venezuela, with minimal exposure to industrialization.1
What they found upends decades of assumptions.
- 115 previously unreported bacterial genomes were recovered from Yanomami skin—representing 59% of all reconstructed prokaryotic genomes in the dataset.
- Yanomami skin was dramatically more diverse: ~80% richer and ~67% more diverse (Shannon index) than western skin at sebaceous sites (p < 0.001).
- Skin conditions like acne, rosacea, and psoriasis—common in industrialized societies—are virtually unreported in hunter-gatherer populations with this level of microbial diversity.
- A western expeditioner who lived with the Yanomami acquired their complex skin microbiome—then lost it upon returning to an industrialized environment.
The implication is disquieting: what modern dermatology calls "healthy" skin—low microbial complexity, dominated by Cutibacterium and Malassezia—may actually represent an impoverished, industrialization-depleted shadow of the ancestral state.
The Yanomami: A Window Into Ancestral Skin
The Yanomami are indigenous to the Amazon rainforests of Venezuela and Brazil. They live in open, communal structures called shabonos—naturally derived shelters with no dividing walls and a natural forest ground floor, situated near rivers where community members fish, bathe, and collect water. Their daily lives involve constant contact with soil, water, plants, and forest environments.
This matters because their skin is in continuous dialogue with the microbial world around them. And the data shows it: Yanomami skin taxa clustered more closely with local soil from the shabono entrance trail than with creek water, and genera like Brachybacterium, Deinococcus, Janibacter, Microbacterium, and Micrococcus were co-detected in both skin and soil samples. Their skin isn't just "on" them—it's ecologically interwoven with their environment.
One of the study's co-authors, David Good, has a deeply personal connection to this research. Good is the son of a Yanomami woman named Yarima, who returned to her tribe when he was a child, separating them for over 30 years. His journey to reunite with her and understand both worlds is the subject of Wayumi, a documentary that premiered at DOC NYC in 2025 and received a Special Mention from the jury for its "strikingly honest two-way fish-out-of-water story about family, belonging, and the effort to bridge two worlds." Good now leads the Yanomami Foundation and co-authored the Durack study—bridging the personal and the scientific in a way that gives this research unusual depth.
More Species, Less Aggression: The Staphylococcus Twist
Here's where it gets counterintuitive. We tend to think of Staphylococcus as a genus to worry about—S. aureus is the villain behind everything from skin infections to MRSA. So you might expect that the Yanomami, with all their microbial richness, would be crawling with dangerous staph.
The opposite was true.
Yanomami skin: Higher Staphylococcus species diversity—including S. aureus, S. hominis, S. haemolyticus, S. saprophyticus, and S. arlettae. But their virulence profile was weighted toward attachment and colonization factors (like the surface protein SdrC-E), not pathogenesis.
Western skin: Fewer Staphylococcus species—but enriched for antibiotic resistance genes and pathogenesis factors, including thymidylate synthase (ThyA) and S. epidermidis pathogenicity island (SePI) components.1
More species. Less aggression. The Yanomami staph strains behave more like peaceful neighbors than troublemakers—likely because they exist within a diverse, competitive ecosystem where no single species can dominate and turn pathogenic. In western skin, with fewer competitors and more selective pressure from antibiotics and antimicrobial products, the surviving strains are the ones armed for conflict.
This echoes a principle we see across ecology: diversity promotes stability. A rainforest doesn't have fewer threats than a monoculture farm—it has more checks and balances.
The Interkingdom Network: M. globosa as Gatekeeper
One of the study's most intriguing findings involves the fungus Malassezia globosa. On western skin, the dominant fungal species is typically Malassezia restricta. On Yanomami skin, M. globosa dominated instead—and its presence correlated positively with overall bacterial richness and diversity in both populations.
That cross-population correlation is notable. It suggests M. globosa may function as something like a keystone species—a hub organism that promotes or permits greater microbial complexity. On Yanomami skin, M. globosa formed a dense network of positive co-associations with bacterial genera like Kocuria, Microbacterium, Neisseria, Janibacter, Deinococcus, and Blastococcus. On western skin, by contrast, M. globosa's interaction network was sparse—limited mostly to binary relationships with Cutibacterium (negative) and Staphylococcus (positive).1
There's also growing evidence that M. globosa induces the immunoregulatory cytokine IL-10, which may help prevent colonization by pathogenic microorganisms and modulate skin inflammation. A lower M. restricta/M. globosa ratio is associated with healthier skin outcomes—raising the question of whether our industrialized skin environments systematically select for the wrong Malassezia species.
What the Yanomami Microbiome Actually Does
Diversity isn't just a species count—it's a functional portfolio. When the researchers profiled what the Yanomami skin microbiome was actually doing (via metatranscriptomics of sebaceous skin), they found active metabolic pathways directly relevant to skin health:
- Lipid metabolism (biosynthesis + degradation) → supports barrier integrity by maintaining the lipid matrix of the stratum corneum
- Fermentation and acid production → maintains the acidic pH of the skin surface (~4.5–5.5), which suppresses pathogen colonization and optimizes antimicrobial peptide function
- Reactive oxygen species (ROS) degradation → protects against oxidative stress, including UV-induced damage
- Aromatic compound degradation → may help diffuse microbial virulence factors
- Hormone metabolism → potentially modulates local endocrine signaling at the skin surface
Compare this to western skin, where the dominant functional signatures were cofactor biosynthesis, carbohydrate degradation, and amino acid metabolism—metabolic housekeeping rather than active barrier defense.1
This isn't just a microbiome that's more diverse. It's one that's actively protecting the skin—fortifying the barrier, managing pH, providing antimicrobial defenses, and mitigating the oxidative stress that drives photoaging and inflammatory skin disease. These are functional outputs of diversity, not just species counts on a list.
The Expeditioner Experiment: You Can Gain It—and Lose It
Perhaps the most striking part of the study is what happened when people crossed between these two microbial worlds.
A western male expeditioner was sampled before, during, and after living with the Yanomami community for several weeks. Over the course of his immersion—sharing their daily practices, sleeping in the shabono, bathing in the river—his skin microbiome transformed. Diversity increased. Composition converged toward Yanomami patterns. Environmental genera like Dietzia, Kocuria, Micrococcus, Brevibacterium, Brachybacterium, Deinococcus, Yimella, and Janibacter appeared on his skin.
Then he went home. And those genera vanished.
Western expeditioner → Amazon: Skin microbiome diversified and converged toward Yanomami composition during immersion. All Yanomami-associated genera were lost upon return to an industrialized setting.
Yanomami traveler → United States: A Yanomami family member who accompanied the expeditioner to the US showed rapid loss of indigenous cutaneous microbiota within approximately two weeks.1
The takeaway is both hopeful and sobering. Hopeful because it demonstrates that the adult skin microbiome is plastic—it can be meaningfully altered through environmental exposure. Sobering because our industrialized environment doesn't just fail to support this diversity—it actively strips it away. The buildings we live in, the products we use, the time we spend indoors—all of it selects against the environmental microbes that may have coevolved with human skin for millennia.
The Genera We're Losing
These aren't obscure lab curiosities. They are prominent, functional members of what appears to be a more complete skin ecosystem—and they are absent or rarely detected on industrialized skin:
Corynebacterium mucifaciens · Kocuria · Micrococcus aloeverae · Brachybacterium · Janibacter · Dietzia · Deinococcus · Brevibacterium · Microbacterium · Yimella
All prominent members of Yanomami cutaneous microbiota. All lost upon adoption of an industrialized lifestyle. All acquired by a western visitor during Amazonian immersion—and all lost again within weeks of returning home.1
Several mechanisms likely drive this loss. We spend roughly 90% of our time indoors, limiting exposure to environmental microbial diversity. Alkaline soaps, detergents, and antimicrobial products disrupt the acid mantle and strip surface lipids that support commensal colonization. Systemic antibiotic exposure—especially early in life—impacts skin microbiome diversity acutely and may have lasting effects. Even our diets and birth practices may narrow the diversity inoculum we receive.
The frequency of inflammatory skin diseases—acne, atopic dermatitis, rosacea, psoriasis—inversely correlates with cutaneous microbial diversity along an urbanization gradient. Hunter-gatherer populations show the highest diversity and the lowest disease burden. We're not just losing species. We may be losing the ecological infrastructure that keeps our skin healthy.
What Can You Actually Do About It?
We obviously can't all move to the Amazon. But this research points clearly in one direction: diversity and coexistence over sterility. Here are evidence-informed shifts worth considering:
- Reconsider constant antibacterial products. Antibacterial soaps, wipes, and harsh cleansers don't just remove pathogens—they strip the commensal communities that keep pathogens in check. Most daily cleansing doesn't require antimicrobial agents.
- Spend more time outdoors. Direct contact with natural environments—soil, green spaces, natural water—exposes skin to the diverse environmental microbes that were ubiquitous for most of human evolutionary history and are now largely absent from indoor life.
- Support barrier health rather than over-stripping. The acid mantle (pH ~4.5–5.5) is maintained in part by microbial fermentation. Over-cleansing with alkaline products disrupts this, creating conditions that favor pathogen colonization over commensal stability.
- Think about skincare as ecosystem management. The most resilient skin isn't sterile skin—it's skin with a diverse, cooperative microbial community actively maintaining barrier integrity, pH, antimicrobial defense, and oxidative stress protection.
The Bigger Picture
This study doesn't just challenge dermatological assumptions—it raises uncomfortable questions about how modern life reshapes our biology. If our skin is this important an interface with the environment, what other benefits are we forfeiting by living such sanitized lives? How might this change our approach to everything from urban planning to childhood development?
The Yanomami data provides a compelling hypothesis: environmental microbial richness is protective. Whether the functional benefits of a diverse, environmentally enriched skin microbiome can be restored in industrialized individuals—through deliberate supplementation, environmental design, or lifestyle change—is the central translational question.
But the expeditioner experiment tells us something important: the adult skin microbiome is plastic enough to be meaningfully altered. The door isn't closed. We just have to stop waging war on the microbial world and start figuring out how to live with it again.
- The Yanomami harbor a skin microbiome of strikingly greater complexity than industrialized populations, including 115 bacterial genomes never before reported
- Their skin is ~80% richer and ~67% more diverse at sebaceous sites—yet they have virtually none of the inflammatory skin diseases common in modern societies
- Staphylococcus species on Yanomami skin are more diverse but less virulent—armed for coexistence, not conflict
- The fungus M. globosa may act as a keystone species, promoting bacterial diversity and modulating inflammation across populations
- Functional pathways on Yanomami skin actively fortify the barrier, maintain pH, degrade oxidative stress, and produce antimicrobial defenses
- A western visitor acquired the Yanomami microbiome during immersion and lost it upon returning home—the skin microbiome is plastic but environmentally dependent
- What we call "healthy skin" in dermatology may describe an industrialization-depleted state, not a universal optimum
- The path forward: diversity and coexistence over sterility—more time in nature, fewer antimicrobial products, skincare that works with your microbiome
Stay curious. Take care of your microbes.
Co-author David Good's personal story is also the subject of Wayumi, a documentary by filmmaker Andrew Balcof that premiered at DOC NYC in 2025. The film follows Good's journey to reunite with his Yanomami mother, Yarima, after a 30-year separation—a "meditation on resilience, cultural survival, and the ties that endure across time and distance." It received a Special Mention from the DOC NYC jury. Learn more about the film's release via Grasshopper Films.
References
- Durack J, Piceno Y, Vuong H, et al. Yanomami skin microbiome complexity challenges prevailing concepts of healthy skin. Nat Commun. 2025;16:5542. doi:10.1038/s41467-025-60131-7
- Byrd AL, Belkaid Y, Segre JA. The human skin microbiome. Nat Rev Microbiol. 2018;16(3):143-155.
- Cordain L, Lindeberg S, Hurtado M, et al. Acne vulgaris: a disease of Western civilization. Arch Dermatol. 2002;138(12):1584-1590.
This post accompanies the Lit Review Friday episode of Learn Something with Thaena. Visit Thaena.com to learn more about the science, our patented human-derived postbiotic, and how you can support your own microbial ecosystem.