Autoimmune disease isn't random: the 5 root causes driving it — and what the new endometriosis research says about immune dysfunction

The 5 root drivers of immune dysfunction

Functional medicine keeps coming back to the same five inputs because that's where the biology keeps pointing: food, toxins, gut health, chronic infections, and stress. None of them cause autoimmunity on their own. Together, layered over years, they raise the background level of inflammation until the immune system loses its ability to tell self from non-self.

• Food: ultra-processed foods, refined seed oils, added sugar, and — in susceptible people — gluten and dairy drive intestinal permeability and systemic inflammation (Fasano, 2012, Clinical Reviews in Allergy & Immunology).
• Toxins: endocrine-disrupting chemicals (BPA, phthalates, PFAS), heavy metals, mould toxins and pesticide residues alter immune signalling and are linked to autoimmune risk (Parks et al., 2014, Current Opinion in Rheumatology).
• Gut health: around 70% of the immune system sits in the gut. Dysbiosis and a permeable intestinal barrier (‘leaky gut’) let bacterial fragments cross into circulation and activate immune cells inappropriately (Mu et al., 2017, Frontiers in Immunology).
• Chronic infections: Epstein-Barr virus, Lyme, reactivated viruses and stealth pathogens are now firmly linked to autoimmune onset — EBV alone raises multiple sclerosis risk 32-fold (Bjornevik et al., 2022, Science).
• Stress: chronic psychological stress dysregulates the HPA axis and shifts the immune balance toward a pro-inflammatory Th17 pattern. One large cohort study found stress-related disorders were associated with a significantly higher risk of subsequent autoimmune disease (Song et al., 2018, JAMA).

Autoimmunity isn't a single event — it's cumulative. Food, toxins, gut, infections and stress layered over years is what tips the immune system from responsive to reactive.

Where endometriosis fits: the new immune story

Endometriosis has traditionally been framed as a hormonal disease — too much oestrogen, misplaced tissue, done. The last few years of research have made that framing look badly incomplete. Endometriosis is now understood as a chronic inflammatory condition with clear features of immune dysfunction, and while it isn't formally classified as an autoimmune disease, it shares an unusual amount of biology with them.

Women with endometriosis have altered natural killer (NK) cell function — the immune cells that would normally clear misplaced endometrial tissue don't do their job properly (Thiruchelvam et al., 2015, Human Reproduction). They have elevated pro-inflammatory cytokines (IL-6, TNF-α, IL-1β) in peritoneal fluid, higher rates of autoantibodies, and a documented co-occurrence with autoimmune conditions including Hashimoto's, lupus, coeliac disease, inflammatory bowel disease and rheumatoid arthritis (Shigesi et al., 2019, Human Reproduction Update — a meta-analysis of over 1.4 million women).

A 2023 review in Frontiers in Immunology went further, describing endometriosis as a condition of ‘immune imbalance and chronic inflammation’ in which macrophage dysfunction, impaired NK cytotoxicity and Th17-driven inflammation together allow ectopic tissue to survive, invade and cause pain. In other words: the immune system in endometriosis is behaving in ways that look strikingly familiar to anyone who works with autoimmune disease.

Why this matters for how you treat it

If endometriosis is partly an immune problem, then the treatment plan can't only be hormonal suppression and surgery. Those tools have their place — but they don't touch the underlying inflammation, the gut, the microbiome, the toxin load or the stress physiology that's keeping the immune system inflamed. That's why so many women feel better on the pill or after excision surgery, then relapse: the fire never went out, it was just covered.

The same five drivers that push a person toward autoimmunity are the ones that keep endometriosis inflamed. Address them and you change the pain, the flare frequency, the fatigue, the gut symptoms, and — in the women I see clinically — the sense that their body is at war with itself.

A practical functional medicine framework

This is the same framework I use with clients navigating Hashimoto's, endometriosis, coeliac, PCOS-with-inflammation, or a stack of ‘unexplained’ symptoms that never quite reach a diagnosis. It isn't a protocol — it's a sequence.

• Take inflammatory foods off the plate for 8–12 weeks: ultra-processed foods, refined seed oils, added sugar, alcohol, and — as a trial — gluten and dairy. Rebuild around vegetables, quality protein at every meal (25–35 g), oily fish, olive oil, herbs and spices (turmeric, ginger, garlic).
• Support the gut: fibre 25–35 g/day, fermented foods, polyphenol-rich plants (berries, extra-virgin olive oil, green tea, dark chocolate), and — when indicated — targeted work on dysbiosis, SIBO or intestinal permeability with a practitioner.
• Reduce toxin load: filter drinking water, swap plastic food storage for glass, choose fragrance-free personal care, wash produce, prioritise organic for the ‘dirty dozen’ where possible, and check your home for damp/mould if symptoms are unexplained.
• Investigate infections when the picture fits: EBV reactivation, chronic Lyme, dental infections, and stealth pathogens can drive persistent immune activation. This is territory for a functional medicine practitioner and appropriate testing.
• Rebuild the stress response: sleep 7–9 hours, morning daylight, daily gentle movement, and a real nervous-system practice (breathwork, vagal-tone work, meditation, time outside). Chronic under-recovery is fuel for autoimmunity.
• Get the bloods that actually help: hs-CRP, ferritin, full thyroid panel with antibodies, vitamin D, B12, homocysteine, HbA1c and fasting insulin. In endometriosis, I also look at hormonal balance (day 21 progesterone, oestradiol), and — clinically — inflammatory markers over time.

What the research actually supports

The evidence base for a food-first, gut-first, root-cause approach to inflammatory and autoimmune conditions is stronger than it's ever been. A Mediterranean-style, anti-inflammatory pattern of eating reduces inflammatory markers and improves symptoms in rheumatoid arthritis (Forsyth et al., 2018, Rheumatology International). In endometriosis specifically, higher intakes of omega-3 fatty acids, fruit and vegetables are associated with lower risk and reduced pain (Missmer et al., 2010, Human Reproduction; Parazzini et al., 2013, Reproductive BioMedicine Online).

Vitamin D sufficiency is protective in multiple autoimmune conditions, including MS and Hashimoto's (Yang et al., 2013, Clinical Reviews in Allergy & Immunology). Stress-reduction interventions measurably lower inflammatory cytokines. This isn't fringe — it's mainstream biology, just applied more thoughtfully than a symptom-and-prescription model allows.

A note for the women in the room

If you have endometriosis, or you suspect you do, or you're stacking a few of the ‘minor’ autoimmune-adjacent diagnoses that women collect over the years — Hashimoto's, IBS, migraine, chronic fatigue, PMDD, unexplained skin flares — please don't accept the framing that this is just your lot. The immune biology behind those conditions overlaps enormously with the biology of autoimmunity, and it is genuinely responsive to inputs. Not overnight. Not perfectly. But meaningfully, and often more than the standard care pathway suggests.

References

• Angum F, Khan T, Kaler J, Siddiqui L, Hussain A. The prevalence of autoimmune disorders in women: a narrative review. Cureus. 2020;12(5):e8094.
• Fasano A. Leaky gut and autoimmune diseases. Clin Rev Allergy Immunol. 2012;42(1):71–78.
• Parks CG, Miller FW, Pollard KM, et al. Expert panel workshop consensus statement on the role of the environment in the development of autoimmune disease. Curr Opin Rheumatol. 2014;26(2):119–128.
• Mu Q, Kirby J, Reilly CM, Luo XM. Leaky gut as a danger signal for autoimmune diseases. Front Immunol. 2017;8:598.
• Bjornevik K, Cortese M, Healy BC, et al. Longitudinal analysis reveals high prevalence of Epstein-Barr virus associated with multiple sclerosis. Science. 2022;375(6578):296–301.
• Song H, Fang F, Tomasson G, et al. Association of stress-related disorders with subsequent autoimmune disease. JAMA. 2018;319(23):2388–2400.
• Thiruchelvam U, Wingfield M, O'Farrelly C. Natural killer cells: key players in endometriosis. Am J Reprod Immunol. 2015;74(4):291–301.
• Shigesi N, Kvaskoff M, Kirtley S, et al. The association between endometriosis and autoimmune diseases: a systematic review and meta-analysis. Hum Reprod Update. 2019;25(4):486–503.
• Vallvé-Juanico J, Houshdaran S, Giudice LC. The endometrial immune environment of women with endometriosis. Hum Reprod Update / Front Immunol. 2023 review.
• Forsyth C, Kouvari M, D'Cunha NM, et al. The effects of the Mediterranean diet on rheumatoid arthritis prevention and treatment: a systematic review. Rheumatol Int. 2018;38(5):737–747.
• Missmer SA, Chavarro JE, Malspeis S, et al. A prospective study of dietary fat consumption and endometriosis risk. Hum Reprod. 2010;25(6):1528–1535.
• Parazzini F, Viganò P, Candiani M, Fedele L. Diet and endometriosis risk: a literature review. Reprod Biomed Online. 2013;26(4):323–336.
• Yang CY, Leung PSC, Adamopoulos IE, Gershwin ME. The implication of vitamin D and autoimmunity: a comprehensive review. Clin Rev Allergy Immunol. 2013;45(2):217–226.