Glycemic Index, Glycemic Load, Fiber, and Gluten Intake and Risk of Laparoscopically Confirmed Endometriosis in Premenopausal Women

Effect of dietary patterns and nutritional supplementation in the management of endometriosis: a review

Endometriosis is an estrogen-dependent chronic inflammatory disease which causes dysmenorrhea, chronic pelvic pain, and infertility in women of childbearing age, significantly impacting their quality of life and physical and mental health. The etiology of endometriosis remains unclear, with oxidative stress and inflammation currently thought to play pivotal roles in its pathophysiology. Epidemiological studies and clinical trials indicate that varying dietary patterns and specific nutrient supplementation can influence oxidative stress markers and levels of inflammatory factors and related pathways, potentially impacting the progression of endometriosis. In this review, we summarize the roles of oxidative stress and inflammation in endometriosis and thoroughly examine the current understanding of the effect of dietary patterns and nutrient supplementation in treating endometriosis. This study suggests that nutrients may prevent the occurrence of endometriosis by modulating levels of inflammatory factors, regulating angiogenesis, and influencing the metabolism of estrogen pathways. The findings might provide new insights into the treatment of endometriosis patients and the potential benefits of dietary patterns and nutrient supplementation in patients with endometriosis.

Exploring the Association Between Dietary Fruit Intake and Endometriosis: A Systematic Review and Meta-Analysis

Background/Objectives: Endometriosis is a chronic gynecological disorder affecting up to 10% of women of reproductive age. The etiology of endometriosis remains unclear; however, there is growing interest in identifying modifiable risk factors, particularly dietary influences. The present study aims to systematically evaluate the association between fruit consumption and the incidence of endometriosis. Methods: A comprehensive systematic search was conducted across PubMed, Embase, Web of Science, and Google Scholar for studies published from 1 January 1990 to 30 September 2024. Relevant data were extracted and categorized, and the methodological quality of the included studies was assessed using the Joanna Briggs Institute (JBI) checklists. Additionally, meta-analyses were performed using STATA 18.0 to compare daily and weekly fruit consumption among women with and without endometriosis. Results: The analysis included six studies comprising 3689 women with endometriosis and 1463 controls. The meta-analysis revealed no significant association between daily fruit consumption and the risk of endometriosis (odds ratio (OR): 0.95; 95% confidence interval (CI): 0.90-1.01). Similarly, weekly fruit consumption did not demonstrate a significant link to endometriosis risk (OR 1.03, 95% CI: 0.78-1.35). The assessment of publication bias using Begg's and Egger's tests, along with contour-enhanced funnel plots, indicated the absence of publication bias in the data across both analysis groups. Conclusions: This study indicates that fruit consumption does not significantly influence the risk of developing endometriosis. Additional research is necessary to examine preferred dietary interventions for populations affected by this condition.

Role of macronutrients, dairy products, fruits and vegetables in occurrence and progression of endometriosis: A summary of current evidence in a systematic review

Background

Current evidence on the role of macro- and micronutrients in the aetiopathogenesis of endometriosis is controversial.

Objectives

In this systematic review, we aimed to investigate the effect of macronutrients, dairy products, fruits, and vegetables on the occurrence and progression of endometriosis.

Materials and Methods

A systematic literature review of eligible articles retrieved from medical databases, including PubMed, Cochrane, and Academic Search, was performed from inception to May 2023.

Main outcome measures

The role of nutritional diet effects in endometriosis.

Results

Our search yielded 12 studies, including five prospective cohort trials and seven case-control studies. The analysis of this literature supports the idea that processed and unprocessed red meat increases the risk of endometriosis, while no conclusive evidence exists about the effects of other protein sources on the disease. Studies on total fat consumption, including monounsaturated, polyunsaturated, saturated, and trans-unsaturated fats, do not suggest a definitive association with endometriosis. Green leafy vegetables and fresh fruit consumption may reduce the risk of endometriosis. Furthermore, the evidence regarding fibre consumption is not conclusive. Dairy products were found to have a risk-reducing effect on the disease. However, there was no consensus about the role of vitamin D in endometriosis.

Conclusions

The certainty of the relationship between endometriosis and outcomes of nutritional factors was "very low" to "low," which limits current literature from being applied for conclusive interpretations. Further large-scale randomised trials and consequent meta-analyses are recommended for high-level evidence.

What is new?

This article presents an overview of evidence-based studies on the relationship between endometriosis and macronutrients. In addition, the possible influence of other nutritional variables on the development of endometriosis and the limitations of nutritional studies.

Dietary and Nutritional Interventions for the Management of Endometriosis

Endometriosis is a chronic, complex, systemic inflammatory condition that impacts approximately 190 million girls and women worldwide, significantly impacting their quality of life. The effective management of endometriosis requires a multi-disciplinary and holistic approach, one that includes surgical and medical management, such as a laparoscopy and a chronic medical management plan, as well as dietary, nutritional, and lifestyle adjunct interventions, such as pelvic pain physiotherapy and acupuncture. There is growing evidence to support the role of dietary and nutritional interventions in the adjunct management of endometriosis-related pain and gastrointestinal symptoms. However, the implementation of these interventions is often not regulated, as patients with endometriosis often adopt self-management strategies. Diet and nutrition can modulate key players integral to the pathophysiology of endometriosis, such as, but not limited to, inflammation, estrogen, and the microbiome. However, it is unclear as to whether diet plays a role in the prevention or the onset of endometriosis. In this review, we discuss three key players in the pathogenesis of endometriosis-inflammation, estrogen, and the microbiome-and we summarize how diet and nutrition can influence their mechanisms, and consequently, the progression and manifestation of endometriosis. There is a major need for evidence-based, non-invasive adjunct management of this debilitating disease, and diet and nutritional interventions may be suitable.

A cross-sectional study on the relationship between dietary fiber and endometriosis risk based on NHANES 1999-2006

Endometriosis is a chronic inflammatory disease and an estrogen-dependent disease, so dietary factors that can modulate estrogen activity may be clinically important. Dietary fiber, widely distributed in vegetables and fruits, is closely associated with a plant-based diet. Therefore, this study aims to analyze and explore the relationship between dietary fiber intake and the risk of endometriosis providing insights for future clinical significance and treatment approaches. This cross-sectional study obtained data from the National Health and Nutrition Examination Survey (NHANES) 1999-2006 for women aged 20-54 years. A total of 2840 subjects were finally included for analysis, 2599 (91.51%) in the non-endometriosis group and 241 (8.49%) in the endometriosis group. The study used dietary fibre intake as exposure variable and endometriosis risk as outcome variable. Through the use of multiple regression modelling, subgroup analyses, smoothed curve fitting, and threshold effect tests, we uncovered a significant link between exposure and outcome. In Model 2 (Multiple regression equation model after adjusting all confounding variables), after adjusting for confounders, dietary fiber intake was negatively associated with the likelihood of developing endometriosis(OR = 0.588, 95% CI = 0.360-0.959, p = 0.041). In subgroup analyses stratified by age, race, BMI, educational level, hypertension, diabetes,and hyperlipidemia, significant interactions were visualised from smoothed fitted curves. In the cross-sectional study, a connection was observed between a higher intake of dietary fiber and a decreased risk of endometriosis.

[The importance of nutrition in the prevention of endometriosis - Systematic review]

Introduction

Background and objective: endometriosis is a hormone-dependent disorder characterized by the presence of endometrial-like tissue in extrauterine sites, which can trigger a chronic inflammatory reaction. This disease mainly affects women of childbearing age and can have a negative impact on their physical, mental and social well-being. There are eating patterns considered as anti-inflammatory, such as the Mediterranean diet, which could help in the prevention and treatment of endometriosis. The objective of this review was to know the relationship between the consumption of different food groups and the prevention of endometriosis. Materials and methods: a systematic review was carried out following the PRISMA methodology. PubMed, Scopus, Cochrane Library and Web of Science databases were consulted. Studies published between 2013 and 2023 were selected, accessible in full text, written in English and Spanish and including a sample of women with endometriosis and/or healthy women, in addition to evaluating the relationship between diet and endometriosis. Unrelated articles, systematic reviews or meta-analyses, pilot studies and studies conducted in animals were excluded. Results: a total of ten studies were included. The consumption of fruits, vegetables (not cruciferous), dairy products, fish, potatoes, legumes, vitamins (A, C, D and B12), monounsaturated and polyunsaturated fatty acids and minerals (calcium, potassium and magnesium) seems to reduce the risk of endometriosis. Conclusions: further studies investigating the relationship between consumption of different food groups and risk of endometriosis are needed.

A gluten-free diet for endometriosis patients lacks evidence to recommend it

Endometriosis is an estrogen-dependent chronic disease characterized by the presence of endometriumlike tissue outside the uterus and is often associated with symptoms, such as dysmenorrhea, dysuria, dyschezia, chronic pelvic pain, and infertility. Moreover, women diagnosed with endometriosis can report gastrointestinal symptoms, including bloating, constipation or diarrhea, and abdominal cramping, which can be associated with irritable bowel syndrome and can result in the misdiagnosis of endometriosis as irritable bowel syndrome at first. Treatment usually involves hormonal therapy, pain management, surgery, and/or assisted reproductive techniques in case of infertility. Nonetheless, these treatment methods can be insufficient for alleviating symptoms or can have unacceptable side effects, leading to noncompliance. Therefore, women often apply self-management strategies, including dietary interventions. One of the diets frequently suggested as a tool to manage endometriosis-related symptoms on social media and patient forums is a gluten-free diet. Although a gluten-free diet has been proven effective in managing nonceliac wheat sensitivity or celiac disease, its effectiveness in endometriosis remains uncertain. The Nurses' Health Study II found it unlikely that gluten intake was a strong factor in endometriosis etiology and symptomatology. To the best of our knowledge, the most frequently cited and sole published intervention study on the efficacy of a gluten-free diet for endometriosis has several important limiting factors, including the absence of a control group. In addition, gluten consumption is highly susceptible to a placebo effect and a nocebo effect, where women might experience symptom relief after eliminating gluten and return of symptoms after they consume gluten again, solely because they believe that gluten is bad for them. Despite the inverse association between body mass index and endometriosis and between a gluten-free diet and increased body mass index, this is an association, and no causality was proven. In addition, other factors should be taken into consideration. Of note, a gluten-free diet is expensive, has limited availability, and has a significant effect on quality of life. Moreover, without proper dietary guidance, it may adversely affect the gastrointestinal microbiome. Therefore, scientifically substantiated advice regarding the use of a gluten-free diet for endometriosis-related symptoms is currently not available, and a gluten-free diet should be discouraged unless there is an additional diagnosis of nonceliac wheat sensitivity or celiac disease.

Impact of lifestyle and dietary modifications for endometriosis development and symptom management

PURPOSE OF REVIEW

Management of endometriosis is often complex and poorly studied. Patients with endometriosis have interest in how their lifestyle may affect their diagnosis. Self-management and lifestyle changes are often used as adjunct therapy, but best practices are not concrete in treatment guidelines.

RECENT FINDINGS

Lifestyle impact on endometriosis and possible self-management treatment therapies are reviewed. Overall, there is a need for future studies in all topics. Data suggest a link between endocrine-disrupting chemicals (EDCs), particularly persistent EDCs, and endometriosis. More work is needed to isolate and quantify exposures and explore their connection to endometriosis in order to provide guidance for clinical practice recommendations. There is insufficient evidence to support a superior diet for management of endometriosis; however, the Mediterranean diet may have the most benefit without nutrition concerns. Exercise may be another tool to improve endometriosis symptoms, but once again data are limited and best type and frequency is not well studied. Best evidence supports body-mind practices such as yoga, although new evidence suggests benefit from a holistic combination of several types of exercises.

SUMMARY

Overall, data on lifestyle effects and associated therapies are limited. Future high-quality studies are needed to guide practice.

The Association Between Daily Intake of Dietary Supplements and Self-Reported Endometriosis: A NHANES-Based Study

Dietary supplements are gaining recognition as potential influencers of female reproductive health, but their connection to endometriosis risk remains underexplored. This study addressed this gap, examining the impact of daily dietary supplement intake on the initiation and progression of endometriosis. To explore this, a cross-sectional study was conducted involving 3950 participants representative of the US population from the 1999-2006 National Health and Nutrition Examination Survey (NHANES). Infertility was determined by a question on year-long attempts to become pregnant. Unweighted and weighted multivariate logistic regression analyses assessed the association between dietary supplements and endometriosis risk. Subgroup analysis was conducted based on the participants' body mass index (BMI). The results revealed intriguing patterns. Specifically, higher dietary fiber content (Q4 vs Q1: OR = 0.56, 95% CI = (0.37,0.84), P = 0.0062) and density (Q4 vs Q1: OR = 0.55, 95% CI = (0.38,0.81), P = 0.0035) were linked to reduced risk of endometriosis. Protein content (Q4 vs Q1: OR = 0.47, 95% CI = (0.31,0.74), P = 0.0011) and density (Q4 vs Q1: OR = 0.63, 95% CI = (0.45,0.88), P = 0.0096) similarly exhibited a negative association with endometriosis risk. Interestingly, when stratified by BMI, these effects were pronounced in normal-weight women, whereas they were not evident in the overweight and obese subgroup. Protein content and density showed no significant associations across subpopulations. In conclusion, this study established a negative relationship between dietary fiber and endometriosis, particularly notable in normal-weight women. Future research is essential to validate these findings and establish a causal link between dietary fiber and endometriosis.

Diet in Prevention and Treatment of Endometriosis: Current State of Knowledge

PURPOSE OF REVIEW

Endometriosis (EM) is a chronic gynecological disease that affects about 10% of women worldwide. It is characterized by the implantation of endometrial cells at ectopic sites. The most common symptom of EM is painful menstruation, which can often lead to chronic pelvic pain that significantly worsens the quality of life. Because some disease-related processes, such as inflammation, hormonal activity, menstrual cycle, or prostaglandin metabolism, can be modified by diet, nutrition may have a significant impact on development and treatment of EM. The purpose of this article was to overview the current knowledge regarding the dietary management of endometriosis.

RECENT FINDINGS

The attention of researchers has so far concentrated mainly on the role of nutrition in the risk of developing EM, while less attention has been paid to examining the use of diet in the treatment of the disease. Current studies focus primarily on various dietary components that have antiproliferative, anti-inflammatory, antioxidant, analgesic, and estrogen-lowering properties. Exploring different ways of coping with endometriosis can make a significant contribution to improving the quality of life of women at risk or diagnosed with EM.

How Can Selected Dietary Ingredients Influence the Development and Progression of Endometriosis?

Endometriosis is a chronic, hormone-dependent disease characterized by the presence of endometrial tissue in ectopic locations. Since the treatment options for this disease are still limited, and the cure rate is unsatisfactory, the search for ways to treat symptoms and modify the course of the disease is of key importance in improving the quality of life of patients with endometriosis. So far, the literature has shown that nutrition can influence endometriosis through hormonal modification and altering the inflammatory or oxidative response. Since the importance of nutrition in this disease is still a subject of scientific research, we aimed to summarize the current knowledge on the role of dietary modifications in endometriosis. Our review showed that nutrients with anti-inflammatory and antioxidant properties, including most vitamins and several trace elements, may influence the pathogenesis of endometriosis and can be considered as the nutrients preventing the development of endometriosis. However, despite the many discoveries described in this review, further interdisciplinary research on this topic seems to be extremely important, as in the future, it may result in the development of personalized therapies supporting the treatment of endometriosis.

The effect of dietary interventions on pain and quality of life in women diagnosed with endometriosis: a prospective study with control group

STUDY QUESTION

What is the influence of dietary interventions, namely the low fermentable oligo-, di-, mono-saccharides, and polyols (Low FODMAP) diet and endometriosis diet, on endometriosis-related pain and quality of life (QoL) compared to a control group?

SUMMARY ANSWER

After adhering to a dietary intervention for 6 months, women with endometriosis reported less pain and an improved QoL compared to baseline whereas, compared to the control group, they reported less bloating and a better QoL in 3 of 11 domains.

WHAT IS KNOWN ALREADY

Standard endometriosis treatment can be insufficient or may be accompanied by unacceptable side effects. This has resulted in an increasing interest in self-management strategies, including the appliance of the Low FODMAP diet and the endometriosis diet (an experience-based avoidance diet, developed by women with endometriosis). The Low FODMAP diet has previously been found effective in reducing endometriosis-related pain symptoms, whereas only limited studies are available on the efficacy of the endometriosis diet. A survey study recently found the endometriosis diet effective in improving QoL but currently no guidelines on use of the diet exist.

STUDY DESIGN, SIZE, DURATION

A prospective one-center pilot study was performed between April 2021 and December 2022. Participants could choose between adherence to a diet-the Low FODMAP diet or endometriosis diet-or no diet (control group). Women adhering to a diet received extensive guidance from a dietician in training. The follow-up period was 6 months for all three groups. For all outcomes, women adhering to the diets were compared to their baseline situation and to the control group.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We included women diagnosed with endometriosis (surgically and/or by radiologic imaging) who reported pain scores ≥3 cm on the visual analogue score (0-10 cm) for dysmenorrhea, deep dyspareunia, and/or chronic pelvic pain. The primary endpoint focused on pain reduction for all pain symptoms, including dysuria, bloating, and tiredness. Secondary endpoints, assessed via questionnaires, focused on QoL, gastro-intestinal health, and diet adherence.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 62 participants were included in the low FODMAP diet (n = 22), endometriosis diet (n = 21), and control group (n = 19). Compared to their baseline pain scores, participants adhering to a diet reported less pain in four of six symptoms (range P < 0.001 to P = 0.012) and better scores in 6 of 11 QoL domains (range P < 0.001 to P = 0.023) after 6 months. Compared to the control group, analyzed longitudinally over the 6-month follow-up period, participants applying a diet reported significant less bloating (P = 0.049), and better scores in 3 of 11 QoL domains (range P = 0.002 to P = 0.035).

LIMITATIONS, REASONS FOR CAUTION

No sample size was calculated since efficacy data were lacking in the literature. In order to optimize dietary adherence, randomization was not applied, possibly resulting in selection bias.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests that women could benefit from adherence to a dietary intervention, since we found lower pain scores and better QoL after 6 months. However, caution is implied since this is a pilot study, no sample size was calculated, and data on long-term effects (>6 months) are lacking. The results of this pilot study underline the importance of further research and the drawing up of guidelines.

STUDY FUNDING/COMPETING INTEREST(S)

A.v.H. reports receiving a travel grant from Merck outside the scope of this study. J.W., S.V., J.T., and B.D.B. have no conflicts of interest to report. A.d.V. reports having received KP-register points for internship guidance of J.W., performing paid consultations with endometriosis patients outside the study and receiving reimbursements for educational lectures at the local hospital (Albert Schweitzer Ziekenhuis, Dordrecht, the Netherlands). A.S. reports having received expenses for travel and hotel costs as an invited speaker from ESHRE. This was outside the scope of this study. M.v.W. reports that she is a Co-Ed of Cochrane Gynecology and Fertility. V.M. reports receiving travel and speaker's fees from Guerbet and research grants from Guerbet, Merck and Ferring. The department of reproductive medicine (V.M.) of the Amsterdam UMC, location VUmc, has received several research and educational grants from Guerbet, Merck and Ferring not related to the submitted work.

TRIAL REGISTRATION NUMBER

N/A.

Endo Belly: What Is It and Why Does It Happen?-A Narrative Review

Endometriosis is a chronic inflammatory disease where endometrial-like lesions settle outside the uterus, resulting in extensive inflammatory reactions. It is a complex disease that presents with a range of symptoms, with pain and infertility being the most common. Along with severe dysmenorrhea, cyclic and acyclic lower abdominal pain, cyclic dysuria and dyschezia, dyspareunia, and infertility, there are also nonspecific complaints that can cause confusion and make endometriosis the chameleon among gynecological diseases. These symptoms include unspecific intestinal complaints, cyclic diarrhea, but also constipation, nausea, vomiting, and stomach complaints. It appears that in addition to general bowel symptoms, there are also specific symptoms related to endometriosis such as cyclic bloating of the abdomen, known as endo belly. During the second half of the menstrual cycle leading up to menstruation, the abdomen becomes increasingly bloated causing discomfort and pain due to elevated sensitivity of the intestinal wall. Patients with endometriosis exhibit a reduced stretch pain threshold of the intestinal wall. Here, we review the endo belly, for the first time, pathophysiology and the influence of other diseases (such as irritable bowel syndrome-IBS), microbiome, hormonal levels, inflammation, and diet on the presentation of this condition.

Diet associations in endometriosis: a critical narrative assessment with special reference to gluten

Endometriosis is characterized by the presence of endometrium-like tissue outside the uterus. The etiology remains largely unknown. Despite adequate treatment, patients can still experience symptoms or side effects resulting in therapy incompliance and in self-management strategies such as dietary measures is increasing. A gluten free diet is thought to be contributory in reducing endometriosis-related pain, thereby optimizing quality of life. However, data is conflicting and currently provides no evidence for causality. This narrative review aims to put the effect of dietary self-management strategies on endometriosis in a balanced perspective, especially the effect of gluten and a gluten free diet. Several studies have found a strong overlap in symptoms, metabolic and immune responses associated with endometriosis and those associated with celiac disease, ulcerative colitis, Crohn's disease, irritable bowel syndrome and non-celiac wheat sensitivity. However, it remains unclear whether these diseases and/or disorders are causal to an increased risk of endometriosis. Some studies have found a positive effect on the risk of endometriosis, endometriosis-related symptoms and quality of life (QoL) when women either avoided certain nutrients or foods, or applied a specific nutrient supplementation. This includes the avoidance of red meat, an increasing intake of foods rich in anti-oxidants, omega-3, micronutrients and dietary fibers (e.g., fruit, vegetables) and the appliance of a gluten free diet. However, data from the available studies were generally graded of low quality and it was noted that placebo and/or nocebo effects influenced the reported positive effects. In addition, such effects were no longer seen when adjusting for confounders such as overweight, when a translation was made from in vitro to in vivo, or when the nutrients were not supplemented as isolated sources but as part of a mixed daily diet. Finally, some studies showed that long-term adherence to a gluten free diet is often associated with an impaired diet quality and nutrient intake, leading to negative health outcomes and reduced QoL. Concluding, scientific evidence on the efficacy of dietary interventions on well-defined clinical endpoints of endometriosis is lacking and recommending a gluten free diet to women solely diagnosed with endometriosis should therefore not be advised.

Association of fertility diet score with endometriosis: a case-control study

Background and aims

Different factors, such as environmental, epigenetic, genetic and immunological, have been identified as potential risks for developing endometriosis. However, the correlation between dietary patterns and endometriosis is currently unknown. The aim of this study was to explore the potential link between fertility diet score and the odds of endometriosis.

Methods

This study was a hospital-based case-control study that took place in a gynecology clinic in Tehran, Iran, between February 2021 and January 2022. A total of 107 newly diagnosed endometriosis cases and 210 controls were included. The participants' habitual diets were evaluated using a food frequency questionnaire, and their fertility diet score was estimated using a point system based on Chavarro et al.'s criteria. The logistic regression was utilized to calculate the odds ratios (OR) with 95% confidence intervals (CIs).

Results

The study found that women who adherence to fertility diet have a lower odds of endometriosis. This was observed in both the base model and the adjusted model, with a significant decrease in odds of endometriosis by 66% (OR = 0.44, 95%CI = 0.27-0.71, p = 0.001) and 54% (aOR = 0.46, 95%CI = 0.23-0.90, p = 0.022), respectively. Additionally, consuming vegetable proteins and multivitamins were also associated with lower odds of endometriosis. On the other hand, consuming animal proteins, heme iron, and having a high glycemic load were associated with significantly higher odds of endometriosis.

Conclusion

Our research supports the hypothesis that following a fertility diet may decrease the odds of endometriosis in Iranian women. However, these findings should be verified through extensive, prospective studies.

Nutrition in the prevention and treatment of endometriosis: A review

Endometriosis is characterized by the presence of endometrial tissues outside the uterine lining, typically on the external surface of the uterus, the ovaries, fallopian tubes, abdominal wall, or intestines. The prevalence of endometriosis in North America, Australia, and Europe is ~1-5% in women of reproductive age. Treatment options for endometriosis are limited. While over-the-counter medications may be used to reduce acute pain, hormonal treatments are common and may interfere with fertility. In more severe cases, laparoscopic excision procedures and even hysterectomies are used to treat the pain associated with endometriosis. Nutritional interventions may be helpful in the prevention and treatment of endometriosis and associated pain. Reducing dietary fat and increasing dietary fiber have been shown to reduce circulating estrogen concentrations, suggesting a potential benefit for individuals with endometriosis, as it is an estrogen-dependent disease. Meat consumption is associated with greater risk of developing endometriosis. Anti-inflammatory properties of plant-based diets may benefit women with endometriosis. Additionally, seaweed holds estrogen-modulating properties that have benefitted postmenopausal women and offers potential to reduce estradiol concentrations in pre-menopausal women. Furthermore, consumption of vitamin D has been shown to reduce endometrial pain via increased antioxidant capacity and supplementation with vitamins C and E significantly reduced endometriosis symptoms, compared with placebo. More randomized clinical trials are needed to elucidate the role of diet in endometriosis.

Association between dietary inflammatory index and risk of endometriosis: A population-based analysis

Background and aims

Chronic inflammation plays a significant role in the etiology of endometriosis, which might be affected by dietary intake. This study aimed to investigate the association between dietary inflammatory index (DII) and the risk of endometriosis.

Methods

A cross-sectional analysis using data from the National Health and Nutrition Examination Survey (1999-2006) was conducted on 3,410 American participants, among whom 265 reported a diagnosis of endometriosis. DII scores were calculated based on the dietary questionnaire. The association of DII scores with endometriosis was evaluated by adjusted multivariate logistic regression analyzes, which were further investigated in the subgroups.

Results

In the fully adjusted models, the odds ratio (OR) for endometriosis participants in the highest and middle tertiles of DII scores were 1.57 [95% confidence interval (CI): 1.14-2.17] and 1.18 (95% CI: 0.84-1.65), compared to the lowest tertile (P _trend = 0.007). In subgroup analyzes, the significant positive association between DII scores and the endometriosis risk was also observed in non-obese women (OR_tertile3vs1: 1.69, 95% CI: 1.12-2.55; P _trend = 0.012), women without diabetes (OR_tertile3vs1: 1.62, 95% CI: 1.16-2.27; P _trend = 0.005), women with hypertension (OR_tertile3vs1: 2.25, 95% CI: 1.31-3.87; P _trend = 0.003), parous women (OR_tertile3vs1: 1.55, 95% CI: 1.11-2.17; P _trend = 0.011), and women using oral contraceptives (OR_tertile3vs1: 1.63, 95% CI: 1.15-2.30; P _trend = 0.006).

Conclusion

This nationally representative study found that increased intake of the pro-inflammatory diet, as a higher DII score, was positively associated with endometriosis risk among American adults. Our results suggested anti-inflammatory dietary interventions may be promising in the prevention of endometriosis. Further prospective studies are necessary to confirm these findings.