Today’s Dietitian
Vol. 28 No. 3 P. 20
Endometriosis is a complex, chronic, estrogen-dependent inflammatory disorder that affects multiple organ systems and about one in 10 females of reproductive age, causing chronic pain, impairing fertility, and eroding quality of life. Its defining symptom is the growth of lesions of endometrial-like tissue outside the uterus. While these lesions can occur throughout the body, they’re almost always found in the pelvic cavity and are categorized into subtypes based on location.1 Superficial endometriosis produces small, flat lesions on the peritoneum (the membrane lining the abdominopelvic cavity). Ovarian endometriosis produces endometriomas (cysts filled with old blood) within the ovaries. Deep endometriosis, the most debilitating subtype, involves lesions that penetrate 5 mm or more within the peritoneum. Endometriosis lesions are found in up to 50% of women seeking treatment for infertility, even if they are asymptomatic.1,2
About 80% of endometriosis patients experience chronic pelvic pain, which research suggests may result from both tissue damage and nervous system dysfunction, with inflammation playing a key role. On top of the chronic pain, patients may experience acute pain flares during menstruation, sex, defecation, and urination, as well as at other unpredictable times. Many patients also experience fatigue and sleep disturbances and have a higher incidence of other chronic pain or fatigue conditions, including fibromyalgia and chronic fatigue syndrome.1 Patients also report higher levels of depression, anxiety, and low mood, as well as gastrointestinal symptoms such as diarrhea, constipation, bloating, and flatulence.1-3
Diagnosis and Treatment
Endometriosis is a progressive disease whose expression can vary significantly over the course of a patient’s life, often starting in adolescence.1,2 Diagnosis and treatment is challenging, with the average patient remaining undiagnosed for several years. Reasons for this include lack of awareness among patients and primary care physicians, as well as the fact that some endometriosis symptoms overlap with other conditions.1 Another barrier is that the traditional gold standard for diagnosis is direct visualization during surgical laparoscopy, followed by excisional biopsy, followed by histological confirmation. However, some clinical guidelines now call for use of pelvic ultrasound or MRI as a less invasive alternative for diagnosis of ovarian or deep endometriosis.
“One of the most pressing issues in endometriosis care is the eight- to 10-year delay in diagnosis,” says Sarah Rae, RDN, founder of Pacific Endometriosis Nutrition in Seattle. “During those years, patients are often bouncing between specialists for ‘unexplained’ pelvic pain, infertility, and GI distress. As RDNs, we have a unique opportunity to be the first line of support.”
Most treatments for endometriosis involve surgery to remove lesions or medications to suppress ovarian steroid hormones, frequently in combination with NSAIDS, but these options are often ineffective at reducing pain, preventing future growth of endometrial lesions, or reducing gastrointestinal symptoms.2,3 An estimated 40% to 50% of endometriosis patients who undergo surgical treatment experience a return of endometriosis-related pain within five years, and hormone-blocking medications may adversely impact fertility, bone density, and mood, among other aspects of physiology.1,4
Understandably, patients are frustrated and looking for alternatives, which has led to increased use of self-management approaches, including nutrition therapy. “Patients are no longer satisfied with the ‘wait and see’ approach postsurgery,” Rae says. “They are seeking solutions that address the symptoms standard medicine often misses—like the gastrointestinal distress and systemic inflammation that persist even after hormonal suppression and/or endometriosis excision. Nutrition offers them a tangible way to improve their internal environment and, crucially, a sense of empowerment in a journey that often feels out of their control.”
However, current research isn’t robust enough to offer standardized guidance for MNT, which has created an opening for nutrition misinformation, often involving restrictive diets. Results published in 2025 from an international survey on diet and endometriosis involving 2,599 women found that most popular dietary strategies for trying to manage pain symptoms involved reducing or eliminating specific foods or food components. such as alcohol, caffeine, gluten, dairy, added sugar, or red meat.5
Megan Luybli, MS, RDN, LDN, owner of A Soft Place to Land, a Bethlehem, Pennsylvania, multidisciplinary practice specializing in eating disorders and cooccurring conditions, says she feels diet culture is feeding the increased interest in nutrition and endometriosis. “Just like any other medical condition, diet culture tells you that it’s curable by either losing weight, eliminating certain foods, and/or adding in wild supplements.” She says she’s seen the significant role that endometriosis, and attempts to manage it with rigid diets, have played in many clients’ eating disorders, adding that as someone with endometriosis herself, “I feel like I can really speak the language of chronic pain, misdiagnosis, all while dodging diet culture and weight stigma’s grip on what endo treatment is ‘supposed’ to look like.”
What’s Known and Unknown About the Role of Nutrition
Emerging evidence suggests that certain dietary patterns may reduce symptom severity by reducing inflammation and modulating hormone levels.6,7 Several dietary components have been associated with more severe endometriosis symptoms, while others appear to help alleviate symptoms.8 For example, a systematic review and meta-analysis found a significant association between moderate alcohol intake and endometriosis,9 and it’s known that alcohol metabolism increases inflammation as well as influences estrogen metabolism.8 Overall, current evidence indicates that individuals with endometriosis may benefit from adopting a diet rich in antioxidants and anti-inflammatory nutrients while minimizing the intake of proinflammatory foods.8
Because many plant foods are rich in substances that can help reduce or modulate inflammation—such as antioxidant phytochemicals, dietary fiber, and micronutrients—some research has looked at potential benefits of plant-based diets. A 2023 review suggested that vegan diets may help in the prevention and treatment of endometriosis, also noting that red meat is associated with increased risk of endometriosis. However, these conclusions are based largely on observational studies and research related to the anti-inflammatory properties of a plant-based diets, generally.10 Higher intake of omega-3s,11a nutrient of concern in vegan diets, is also protective, and some research suggests dairy may also be protective.12
A small (n=40) cross-sectional observational study among Spanish women found that women with ovarian endometriomas scored significantly lower on the Mediterranean diet and Healthy Eating Index compared with controls. Women with endometriomas or deep endometriosis consumed significantly less dairy than controls.3 Results of a case-control study published in 2025 with 115 women diagnosed with endometriosis and 230 healthy control subjects found that women with greater adherence to the Mediterranean diet had 94% lower odds of endometriosis and those with higher scores on the Healthy Diet Indicator had 95% lower odds.13
Rae, who has endometriosis herself, says she, like many of her patients, was bombarded with highly restrictive dietary advice. “When working with endometriosis patients, I steer clear of restrictive ‘elimination’ mindsets and instead focus on a high-diversity, anti-inflammatory foundation.” She says the Mediterranean diet has the most evidence in research to be helpful in improving endometriosis incidence and pain levels. “The Mediterranean diet remains the gold standard for endometriosis because of its naturally high concentration of omega-3 fatty acids. I encourage patients to prioritize fatty fish, walnuts, and chia seeds.” She points out that omega-3s help dampen the proinflammatory prostaglandins that cause debilitating cramps. “We use vitamins C, E, and polyphenols to combat the high levels of oxidative stress often found in the peritoneal fluid of endo patients. Supporting patients in increasing their antioxidant intake through diet and supplements is helpful for managing pain, improving GI symptoms, and improving fertility if that is their goal.”
Rae also says blood sugar management is important in endometriosis care. “When we see frequent glucose spikes, the body compensates with high levels of insulin. This is problematic because hyperinsulinemia can upregulate aromatase activity—the enzyme responsible for converting androgens into estrogen.” This can potentially fuel lesion growth and lead to irregular menstrual cycles, heavier bleeding, and worsening pain. “In a disease characterized by estrogen dysregulation, we want to keep that conversion to a minimum. I teach my patients to pair their carbohydrates with protein, fiber, and healthy fats. This slows glucose absorption, thereby maintaining a stable hormonal environment and significantly reducing the systemic inflammation that drives pelvic pain.”
Endometriosis, Gut Health, and Nutrition
Limited research—mostly small-scale observational human studies—has found that some endometriosis patients have reduced gut microbial diversity and/or higher abundance of proinflammatory bacterial species,14,15 although it’s unclear if any changes in the gut microbiota are due to the endometriosis itself or to the resulting inflammation.16
Rae says she rarely sees a patient with endometriosis who doesn’t also have some form of GI dysfunction, whether it’s irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), or general dysbiosis. “Managing gut health has been a key part of improving endometriosis symptoms in my patients.”
Meal consistency is important for both blood sugar balance and digestive health, Rae explains. “For one, consistent fueling prevents the ‘starve-then-binge’ cycle that often leads to poor food choices and digestive distress during a flare. Additionally, for patients with SIBO and dysbiosis, meal consistency allows sufficient fasting windows to trigger the migrating motor complex, thereby preventing fermentable buildup that causes ‘endo-belly.’” To further support bowel health, Rae says she focuses on hydration and supporting the gut microbiome with targeted probiotics, fiber, and prebiotic foods.
Many symptoms of endometriosis—abdominal pain, bloating, changes in bowel habits, and food intolerances—can overlap with symptoms of IBS and inflammatory bowel disease (IBD), contributing to delayed diagnosis. Research has shown that IBS prevalence is two to three times higher in patients with endometriosis, and that endometriosis patients have an increased risk of IBD. Even when endometriosis lesions don’t affect the bowels directly, patients may still have gastrointestinal symptoms, which suggests that endometriosis indirectly affects the enteric nervous system, leading to the visceral sensitivity that’s common in these conditions—and that also can exacerbate endometriosis pain. While there’s some evidence that the low-FODMAP diet, typically used to help manage IBS symptoms, may also provide endometriosis symptom relief, research isn’t conclusive.2,7
Rae says she sometimes uses the low-FODMAP diet with her patients but views it as a short-term “Band-Aid” approach. “It can be incredibly effective for managing the acute, debilitating bloating—the ‘endo-belly’—especially for patients preparing for excision surgery or those waiting to begin a SIBO treatment protocol. It provides them with much-needed symptomatic relief and a sense of control during high-stress periods.”
In the long run, she says the diet rarely moves the needle on the deep, inflammatory pelvic pain characteristic of endometriosis. “My goal is always to use the low-FODMAP phase as a bridge (if I use it at all)—reducing the ‘noise’ of GI distress so we can focus on the root causes, treat underlying infections like SIBO, and eventually move toward a diverse, anti-inflammatory Mediterranean-style pattern that is sustainable for a lifetime.”
Luybli says she doesn’t use the low-FODMAP diet with her clients because they also often have a current or past history of eating disorders, and notes that she’s encountered additional GI issues in her endometriosis clients that have led to alternative exploration and diagnoses, such as mast cell activation syndrome and Ehlers-Danlos syndrome.
Future Directions
Both Rae and Luybli point out the gaps in endometriosis research. “Because women’s health is so historically understudied, I would love to see more robust data specifically linking nutrition to pain outcomes and presurgical fertility,” Rae says, adding that she’s also curious if targeted nutritional interventions can manage pain and inflammatory markers to a degree that a patient might be able to delay or even avoid surgery for certain goals.
Luybli notes that researchers have yet to identify how or why endometriosis happens. “We have theories but no concrete answers. In relation to nutrition, we do have some studies that have explored specific diets and whether they help endo symptoms or not. The conclusions are that cutting out food groups is unhelpful. I’d love more research to be done on the intersection between endometriosis, eating disorders, and chronic pain.”
Rae says she views MNT as the bridge between clinical management and daily quality of life. “Endometriosis is a multisystem inflammatory disease; therefore, our approach must be equally broad. Our role is not just about ‘meal plans’; it’s about providing a clinically sound, nonrestrictive framework for a complex, multisystemic disease. By the time a patient reaches a surgeon, they may have suffered for a decade. RDNs can step in much sooner to help manage the inflammatory ‘fire,’ optimize gut health, and support fertility, significantly improving a patient’s quality of life long before they ever step into an operating room.”
— Carrie Dennett, MPH, RDN, is the nutrition columnist for The Seattle Times, owner of Nutrition By Carrie, and author of Healthy for Your Life: A Non-Diet Approach to Optimal Well-Being.
References
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