For many women, autoimmune symptoms don’t arrive all at once. They creep in slowly.
Maybe it starts with a kind of tiredness that feels… different. Or joints that take a little longer to warm up in the morning. Or digestion that suddenly seems more sensitive than it used to be. It’s easy to blame stress, hormones, aging, or just “life.”
So you push through. Because that’s what women do.
But over time, those small changes start to stack up. Fatigue becomes a constant companion. Brain fog makes it harder to focus. Foods you’ve eaten your whole life suddenly leave you bloated or uncomfortable. Sleep doesn’t feel as restorative. Maybe your hair starts thinning, or inflammation shows up in ways you can’t quite explain.
Individually, each symptom seems manageable. Easy to dismiss.
Together, they begin to affect daily life.
For some women, this eventually leads to a diagnosis such as Hashimoto’s thyroiditis, rheumatoid arthritis, lupus, or another autoimmune condition. For others, the symptoms persist without clear answers – leaving them feeling frustrated, dismissed, or stuck.
And at some point, a deeper question emerges: How did my body get here?
Looking Beyond Symptom Management: What Causes Autoimmune Disease?
Modern healthcare is designed to diagnose and manage disease once it’s already taken hold. And while there are tests and medications that can be helpful in many ways, it often leaves a gap – especially for women who’ve been living with symptoms long before anything shows up on a lab test.
By the time fatigue, pain, digestive issues, or brain fog have been building for months or years, it’s completely understandable to wonder what’s actually been happening beneath the surface.
Researchers now understand that autoimmune disease rarely develops from a single cause. Instead, it tends to unfold when several underlying factors quietly overlap over time. One of the clearest ways to understand this is through the Autoimmune 3-Legged Stool.
Autoimmune disease rarely begins with a single cause. It develops when several underlying factors quietly stack up over time.
The Autoimmune 3-Legged Stool
According to this model, three key elements generally need to be present for autoimmune disease to develop:
- Genetic susceptibility
- Environmental triggers
- Intestinal permeability and immune dysregulation
When these three pieces overlap, the immune system can lose some of its ability to distinguish between “self” and “not‑self,” leading it to mistakenly attack the body’s own tissues.
This framework helps shift the question from “What’s wrong with me?” to “What’s been influencing my immune system over time?”
If you’re a visual learner, we created a free handout that walks through this model and helps you reflect on your own story.
Now let’s take a closer look at each leg of the stool.
Leg One: Genetic Susceptibility
Genetics absolutely play a role in autoimmune disease. Certain inherited gene patterns can increase susceptibility to conditions such as rheumatoid arthritis, type 1 diabetes, and celiac disease.
But here’s the encouraging part:
Genes are not destiny.
Studies of identical twins—who share the same DNA—show that one twin may develop an autoimmune condition while the other does not. This tells us that genes create the potential, but something else determines whether that potential becomes reality.
This is where epigenetics comes in. Factors like stress, infections, toxins, and even diet can influence how genes are expressed—essentially turning certain pathways on or off.
Your genes may set the stage, but they don’t write the whole script.
Genetics may open the door, but environment and immune regulation decide whether you walk through it.
Leg Two: Environmental Triggers
Environmental triggers are often the “tipping points” – the moments when a vulnerable immune system finally says, “I can’t keep compensating for this.”
Researchers have identified several potential triggers, including:
- viral or bacterial infections
- chronic stress
- environmental toxins
- hormonal shifts
- certain medications
- dietary factors
One striking example: a large 2022 study in Science found a strong association between Epstein–Barr virus and multiple sclerosis. Not because EBV causes MS on its own, but because it can act like a spark in someone whose immune system is already primed.
Environmental exposures also influence the gut microbiome, which leads us to the third leg of the stool.
Leg Three: Intestinal Permeability and Immune Dysregulation
Your gut isn’t just about digestion – it’s one of the most active immune hubs in your entire body.
Under healthy conditions, the intestinal lining acts like a smart security system: it lets nutrients in while keeping potentially harmful substances out.
But when that barrier becomes compromised – often called intestinal permeability or “leaky gut” – larger molecules like food proteins or microbial fragments can slip through. This can activate the immune system and contribute to chronic inflammation.
Research led by Dr. Alessio Fasano suggests that increased intestinal permeability may be a necessary component in the development of many, if not most, autoimmune diseases.
What can disrupt the gut barrier?
- chronic stress
- poor diet quality
- microbiome imbalance
- infections
- certain medications
When this gut‑immune disruption overlaps with genetic susceptibility and environmental triggers, the conditions for autoimmunity may be present.
Why This Model Matters
The 3‑Legged Stool model doesn’t just explain what causes autoimmune disease – it highlights where you do have influence.
You can’t change your genetics.
But many of the environmental and lifestyle factors that shape immune regulation are modifiable.
Emerging research suggests that nutrition, stress management, sleep, movement, and gut health all play meaningful roles in supporting immune balance.
For many women, addressing these areas can help:
- reduce symptom burden
- support gut barrier function
- improve energy and resilience
- potentially slow disease progression
These changes don’t replace medical care – they complement it. And the impact varies from person to person, which is why personalized guidance can be so valuable.
For many people, autoimmune disease begins years before diagnosis – while symptoms are still small enough to ignore.
A Framework for Moving Forward
If this model helps you make sense of your own health story, you’re not alone. Many women feel a sense of relief when they finally see how the pieces fit together.
And if you’d like a visual summary of the 3‑Legged Stool, we’ve created a free handout that walks through the model in a clear, easy‑to‑understand way.
If you’re looking for support beyond the basics, our Start Here page explains how we work with women navigating autoimmune symptoms through personalized nutrition and lifestyle strategies.
Final Thoughts
Autoimmune disease is complex, and there is rarely a single cause. But the 3‑Legged Stool model offers a science-backed way to understand how different factors can interact over time to influence immune health.
While you can’t change your genetics, you can influence many of the factors that keep the autoimmune stool standing. By supporting gut health, reducing inflammatory triggers, managing stress, and nourishing your body well, you may be able to weaken the structure that allows autoimmunity to take hold. And sometimes, when enough of those factors shift, the whole stool begins to wobble.
References
Bjornevik, K., Cortese, M., Healy, B. C., Kuhle, J., Mina, M. J., Leng, Y., Elledge, S. J., Niebuhr, D. W., Scher, A. I., Munger, K. L., & Ascherio, A. (2022). Longitudinal analysis reveals high prevalence of Epstein–Barr virus associated with multiple sclerosis. Science, 375(6578), 296–301. https://doi.org/10.1126/science.abj8222
English, J., Connolly, L., & Stewart, L. D. (2024). Increased intestinal permeability: An avenue for the development of autoimmune disease? Exposure and Health, 16, 575–605. https://doi.org/10.1007/s12403-023-00578-5
Fasano, A. (2020). All disease begins in the (leaky) gut: Role of zonulin‑mediated gut permeability in the pathogenesis of some chronic inflammatory diseases. F1000Research, 9, 69. https://doi.org/10.12688/f1000research.20510.1
Global Autoimmune Institute. (2024). Infections and pathogens as triggers of autoimmune disease. https://www.autoimmuneinstitute.org/research_updates/infections-and-pathogens-as-triggers-of-autoimmune-disease/
Kumar, M. M., Yip, L. L., Wang, F., Marty, S. S., & Fathman, C. C. (2025). Autoimmune disease: Genetic susceptibility, environmental triggers, and immune dysregulation. Where can we develop therapies? Frontiers in Immunology, 16, Article 1626082. https://doi.org/10.3389/fimmu.2025.1626082
