Anorexia nervosa is linked to higher rates of autoimmune disease, but the relationship is more complex than simple cause and effect. In one large study, 8.9% of patients with eating disorders had been diagnosed with at least one autoimmune condition, compared to 5.4% of matched controls. That translates to roughly 70% higher odds. Whether anorexia directly triggers autoimmunity, shares root causes with it, or both, is still being untangled.
Which Autoimmune Conditions Are Linked to Anorexia
Several autoimmune diseases show up more often than expected in people with anorexia nervosa. The most commonly reported overlap involves celiac disease, Hashimoto’s thyroiditis, lupus, scleroderma, inflammatory bowel disease, and Behçet’s syndrome. A meta-analysis found that people with anorexia are about 2.4 times more likely to have celiac disease than healthy adults, with roughly 1% of anorexia patients carrying a celiac diagnosis.
Lupus has drawn particular attention. Multiple case reports describe anorexia appearing as what turned out to be an early manifestation of systemic lupus erythematosus, especially in adolescents. In some of these cases, the weight loss and food refusal that looked like a classic eating disorder were actually driven by an undiagnosed autoimmune process. Hashimoto’s thyroiditis, which attacks the thyroid gland and can cause fatigue and weight changes, has also been documented alongside anorexia in multiple studies.
The Relationship Runs Both Directions
One reason this question is hard to answer with a simple yes or no is that the link between anorexia and autoimmunity appears to be bidirectional. Anorexia may create conditions that promote autoimmune disease, but autoimmune diseases can also trigger or mimic anorexia.
Celiac disease and inflammatory bowel disease illustrate this clearly. Both cause gastrointestinal pain, nausea, and discomfort after eating. Over time, that discomfort can lead to food avoidance patterns that look identical to an eating disorder and, in some cases, evolve into one. A person who starts restricting food because eating causes pain may develop the psychological patterns of anorexia even though the original trigger was immunological.
Going the other direction, prolonged starvation reshapes the immune system in ways that could set the stage for autoimmune problems during or after recovery. The body doesn’t simply return to its previous state once nutrition improves. The immune rebalancing that happens with weight restoration may itself be a vulnerable period.
How Starvation Reshapes the Immune System
During active starvation, the immune system actually becomes less inflammatory overall. The body suppresses the types of immune cells (particularly a subset called Th17 cells) most responsible for attacking the body’s own tissues, while preserving regulatory cells that keep immune responses in check. Inflammatory signaling molecules drop. Leptin, a hormone produced by fat tissue that also acts as an immune activator, plummets as body fat disappears.
This suppressed state is why people with severe anorexia are more vulnerable to infections. Paradoxically, it also means that active starvation may temporarily protect against autoimmune flares. Animal studies in mice have shown that calorie restriction prevents or reduces the severity of lupus and other autoimmune conditions by dampening the immune cells that drive those diseases.
The problem likely comes with the transition. When nutrition improves and the body starts rebuilding, the immune system doesn’t always reboot cleanly. Inflammatory markers like IL-6 are elevated during acute anorexia but tend to normalize with weight restoration, suggesting a period of immune recalibration. If the immune system overshoots during recovery, attacking the body’s own tissues in the process, autoimmune disease could result. This rebound hypothesis is plausible but not yet proven in human studies.
Gut Damage as a Possible Trigger
One of the more compelling theories involves the gut lining. Prolonged malnutrition can damage the intestinal barrier, the single layer of cells that separates the contents of your digestive tract from your bloodstream. When this barrier weakens, bacterial products can leak into the circulation and provoke immune responses that wouldn’t normally occur.
In anorexia, this process may go a step further. Bacterial fragments that cross a damaged gut wall can stimulate the production of autoantibodies, immune proteins that mistakenly target the body’s own signaling molecules. Some of these autoantibodies target appetite-regulating hormones, which could worsen the eating disorder itself while simultaneously training the immune system to attack the wrong targets.
That said, research on intestinal permeability in anorexia is still in early stages. The few human studies conducted so far have not confirmed increased “leaky gut” in anorexia patients, even though the theoretical framework is strong. The gut-immune connection remains a promising explanation rather than a confirmed mechanism.
Shared Genetics May Explain the Overlap
Part of the association between anorexia and autoimmune disease may not be causal at all. Instead, both conditions may share genetic roots. A large genome-wide association study identified a significant genetic region on chromosome 12 associated with anorexia nervosa, and that same region had already been flagged as a risk locus for type 1 diabetes and other autoimmune disorders.
This means some people may carry genetic variants that independently raise their risk for both anorexia and autoimmune conditions. If that’s the case, the two diseases appearing in the same person wouldn’t mean one caused the other. They’d be separate consequences of the same underlying genetic vulnerability. This genetic overlap also helps explain why autoimmune diseases sometimes appear before anorexia develops, not just after.
What This Means in Practical Terms
If you have anorexia or a history of it, the takeaway is not that autoimmune disease is inevitable. The absolute numbers remain relatively small: roughly 9 in 100 eating disorder patients in the largest study, compared to 5 in 100 in the general population. But the elevated risk is real enough to be worth paying attention to.
Symptoms worth noting include persistent joint pain, unexplained rashes, chronic fatigue that doesn’t improve with rest, recurring digestive problems, or hair loss that goes beyond what’s typical during malnutrition. These can all signal autoimmune activity. Because anorexia itself causes many of these same symptoms (fatigue, hair thinning, GI distress), autoimmune conditions can be easy to miss or dismiss in someone with an active eating disorder.
The reverse is also worth considering. If you’ve been diagnosed with celiac disease, Hashimoto’s, or another autoimmune condition and notice yourself developing restrictive eating patterns, the autoimmune disease itself may be contributing to those behaviors, whether through GI discomfort, appetite changes, or the psychological burden of managing a chronic illness.