The Importance of Diet in the Treatment of Endometriosis

Abstract

The world of science is increasingly looking for answers to the question of how specific dietary components affect the risk of chronic diseases and assessing their potential to alleviate the severity of individual diseases. This research concerns both the assessment of the benefits of using individual dietary components and those of nutritional models. Endometriosis, due to its chronic and inflammatory nature, is also a topic of interest among scientists, who seek to support its course through proper nutrition. In endometriosis, great interest is focused on dietary patterns such as an anti-inflammatory diet, a gluten-free diet, a low-FODMAP diet, or a Mediterranean diet. An anti-inflammatory diet primarily focuses on fresh vegetables, fruits, seeds, nuts, whole grain products, and healthy sources of protein and fats, including mono- and polyunsaturated fatty acids, eliminating highly processed products, meat products, trans fats, and refined sugars. It is believed that this type of diet may contribute to reducing the severity of endometriosis symptoms and help reduce inflammation. The aim of the review is to identify the main trends in the field of diets supporting the treatment of endometriosis in the last 5 years.

1. Introduction

Diet plays an important role as a non-pharmacological factor in the management of endometriosis. While there is no one-size-fits-all diet that works for all people with endometriosis, certain nutritional aspects can support overall health and reduce the symptoms of the disease [1,2]. Endometriosis is a disease characterized by chronic inflammation that contributes to increased pain and the growth of endometrial tissue outside the uterus. The etiology of endometriosis is not fully known. Endometriosis occurs in North America, Australia, and Europe in approximately 5–10% of women of reproductive age [3]. This disease contributes to symptoms such as infertility, pelvic pain, profound dyspareunia, urination, and interruption of menstruation. It is assumed that apoptosis and the proliferation of endometrial cells are related to the pathogenesis of the disease. Additionally, oxidative stress and inflammation are also associated with the development of the disease [3]. This condition is common after menarche and declines significantly after menopause, leading to the assumption that the disorder is estrogen- and progesterone-dependent. Risk factors associated with endometriosis include age, family history, level of education, age at menarche, and exposure to endocrine-disrupting chemicals. Lifestyle factors include alcohol or caffeine consumption, smoking, and low physical activity, as they affect the level of estrogen in the body and may therefore influence the development of the disease [4]. Depending on the symptoms, extent, and location of lesions, the treatment of endometriosis may vary. Surgery, drug therapy, and a comprehensive, individual approach are the main treatment strategies [5]. An anti-inflammatory diet can help reduce this condition and relieve symptoms. It should be rich in anti-inflammatory ingredients such as leafy vegetables (spinach, chard), berries, nuts (e.g., walnuts), fatty fish (salmon, sardines), and linseed oil, and it should limit potential pro-inflammatory ingredients such as saturated fats, simpler sugars, and processed food products. Hormonal regulation is a very important element. Hormones, especially estrogens, play a key role in the development and severity of endometriosis [6]. Diet can help regulate hormone levels. It is recommended to choose foods rich in dietary fiber as it can help regulate estrogen levels by supporting a healthy metabolism. At the same time, remember that highly processed products may contain chemicals that affect the hormonal balance. Gut health is also important for overall body health, including the regulation of inflammation and hormone metabolism. Pain is the main symptom of endometriosis, which can be partially alleviated by diet. Containing ingredients rich in antioxidants and omega-3 fatty acids, it can relieve inflammation and pain [7]. In some cases, supplementing with vitamin D, omega-3 fatty acids or other ingredients may be helpful. Diet can play a key role in managing the symptoms and course of endometriosis. This effect is mainly related to the anti-inflammatory and hormone-regulating properties of certain foods [6]. Below is an overview of the impact of diet on the course of endometriosis.

2. Research Methodology

For the purposes of this literature review, a literature search was conducted in the online database (PubMed), entering the terms: “diet and endometriosis”, “nutrition and endometriosis”, and “diet components and endometriosis”. The literature search was conducted until October 2024. Reviews, meta-analyses, and original studies presenting results regarding the correlation between diet and diet components and endometriosis were included in this review according to the following criteria: English language and publication in peer-reviewed journals. Duplicates, single case reports/series, and articles written in languages other than English were excluded. The search strategy is summarized in

Table 1. Search strategy.

Characteristic	Search conditions
Search date	Until October 2024
Database	PubMed
Keywords used	“Diet and endometriosis” “Nutrition and endometriosis” “Diet components and endometriosis”
Time period	Research from the last 5 years
Inclusion and exclusion criteria	Type of research: clinical trials, meta-analyses, randomized controlled trials, narrative and systematic reviews, Type of excluded studies: Case reports and case series, opinions Language restrictions: Abstract in English. Only papers available in full text Articles were excluded due to lack of relevance to a given topic, duplicates.

. The PRISMA diagram below (Figure 1), adapted from a template generated from the PRISMA Home 1.6.0., illustrates process of data extraction.

3. Results and Discussion

The PubMed database has filters for full text, free access, and a time limit covering the last 5 years. Entering the keywords “diet and endometriosis” into the PubMed database yielded 86 views, “nutrition and endometriosis” yielded 141 views, and entering “diet ingredients and endometriosis” yielded 6 views. After eliminating duplicates, articles in languages other than English, animal studies, and studies not directly related to diet/nutrition and endometriosis, 60 articles were qualified for review.

3.1. Anti-Inflammatory Compounds in the Diet

3.1.1. Omega-3 Fatty Acids

Omega-3 fatty acids have anti-inflammatory properties. Omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are precursors of eicosanoids with anti-inflammatory properties. Omega-3 fatty acids compete with omega-6 fatty acids for sites in the cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, which leads to a reduction in the production of pro-inflammatory prostaglandins and leukotrienes derived from arachidonic acid (omega-6) [8]. As a result, omega-3 fatty acids reduce inflammation in the body, which is crucial for regulating the symptoms of endometriosis. Studies have shown that supplementing with omega-3 fatty acids can reduce pain associated with endometriosis. Omega-3 fatty acids intake can lead to increased levels of specific proteins: secretory phospholipase A2 type IIa (sPLA2IIa) and fatty acid-binding protein 4 (FABP4). Both have anti-inflammatory effects and can repair damage to membrane phospholipids, and they contribute to vascular endothelial cell migration in the angiogenesis process associated with endometriosis. Activation of the autonomic nervous system through inflammation-induced release of neurotrophic and neuroprotective cytokines is a suggested contributing factor to endometriosis-related pain [9]. Nodler showed that 6 months of fish oil supplementation did not lead to a statistically significant change in pain in girls and young women with endometriosis compared to placebo. However, there was a trend towards improvement in the severity of pelvic pain and in the improvement of well-being [10]. This may be related to less production of pro-inflammatory prostaglandins, which are responsible for pain and cramps. Omega-3 fatty acids can affect the immune system by modulating the immune response and reducing the activity of immune cells involved in the inflammatory process [11,12]. This is important because endometriosis is associated with an abnormal immune response that can lead to chronic inflammation and the formation of adhesions. Omega 6 fatty acids are precursors to pro-inflammatory cytokines that increase pelvic pain [5]. Omega-3 fatty acids may influence estrogen metabolism, which is important in the context of endometriosis because estrogen stimulates the growth of endometrial tissue [10]. There is evidence that a diet rich in omega-3 may help regulate estrogen levels in the body. Omega-3 supplementation has systemic benefits, such as improved cardiovascular health, which is important for the overall health of women with endometriosis. Omega-3 can improve the blood lipid profile, reduce blood pressure, and reduce the risk of cardiovascular disease [11]. Natural sources of omega-3 fatty acids are fatty fish (salmon, mackerel, sardines, trout), flax and chia seeds, walnuts, linseed oil, and evening primrose oil, along with the following dietary supplements: fish oil capsules and algae oil (for vegans) [8].

3.1.2. Antioxidants

Antioxidants, such as vitamin C, vitamin E, and beta-carotene, selenium, or polyphenols, play an important role in the treatment of endometriosis due to their ability to neutralize free radicals, reduce oxidative stress, and alleviate inflammation [6]. Oxidative stress is the result of excessive production of reactive oxygen species (ROS), which can damage cells and tissues. In endometriosis, excess ROS contributes to chronic inflammation and disease progression [13]. Antioxidants neutralize these harmful free radicals, which help protect cells from damage. Antioxidants can modulate the inflammatory response by inhibiting pro-inflammatory factors such as cytokines and chemokines [14]. Reducing inflammation is key to managing endometriosis symptoms because inflammation is the main mechanism leading to pain and endometrial tissue growth. Free radicals can cause DNA damage, which can lead to uncontrolled growth of endometrial cells. Antioxidants protect DNA against oxidative damage, which may help prevent disease progression [14]. Antioxidants can also support immune system function, which is important in endometriosis, where an abnormal immune response often occurs. Improving immune function can help reduce chronic inflammation and symptoms [13,14,15]. For example, vitamin E and C are antioxidants and may help alleviate the role of inflammation in endometriosis. Vitamin E and C supplementation has been shown to reduce pelvic pain, dyspareunia, dysmenorrhea, and the risk of endometriosis [5].

Table 2. Selected sources of natural antioxidants [4,12,14].

Vitamin C	Vitamin E	Beta-Carotene	Polyphenols	Selenium
citrus fruits (oranges, grapefruits), strawberry, pepper, broccoli	nuts (almonds, walnuts), seeds (sunflower), vegetable oils (sunflower oil, wheat germ oil), avocado	carrots, sweet potatoes, pumpkin, spinach	berries (blueberries, raspberries, goji berries), green tea, red wine (in moderation), dark chocolate (high cocoa content)	Brazil nuts, sunflower seeds, fish (tuna, salmon), eggs

presents selected sources of natural antioxidants.

3.1.3. Vitamin B

B vitamins, especially B6, B9 (folic acid), and B12, may play a role in reproductive health and be associated with the risk of endometriosis [6,16]. Vitamin B6 (pyridoxine) may influence estrogen metabolism and hormonal regulation. It has been suggested that vitamin B6 supplementation may help alleviate the symptoms of endometriosis [16]. Folic acid is important for proper cell division and may be important in the prevention of endometriosis. Research suggests that higher folic acid intake may be associated with a lower risk of endometriosis [6]. The direct impact of vitamin B12 intake on endometriosis is less studied, but it is important for overall health and may support the functioning of the nervous system [6].

3.1.4. Vitamin D

Vitamin D (fatty sea fish, fortified dairy products, eggs, sun exposure) has immunomodulatory and anti-inflammatory properties. Vitamin D can reduce inflammation, proliferation, cytokine production, and the expression of growth factors, which has a beneficial effect on alleviating endometriotic changes in patients with endometriosis. This occurs by inhibiting NF-κB activation by promoting the stability of the inhibitor of kappa B protein alpha (IkBα); increasing the expression of mitogen-activated protein kinase phosphatase-1 (MKP-1), leading to the subsequent inhibition of pro-inflammatory cytokine biosynthesis; and by inhibiting cell line proliferation [17]. Research suggests that low vitamin D levels may be associated with a higher risk of endometriosis and with a higher risk of suffering from endometriosis with severe symptoms [5,17]. Vitamin D supplementation can help reduce inflammation and improve overall health [6]. This may be due to the anti- effect of vitamin D by reducing C-reactive protein (CRP) levels [5].

Table 3. Food sources of vitamin D and selected vitamins B [18,19].

Vitamin D	Vitamin B6	Vitamin B9	Vitamin B12
sea fish (eel, cod, salmon, herring, mackerel, Shiitake mushrooms) and, in small quantities, eggs, milk, vegetable oils, and liver	beef, poultry, starchy vegetables, non-citrus fruits, and fortified cereals	dark green leafy vegetables, nuts, beans, dairy products, meat, poultry, grains, and Brussels sprouts	animal products and fortified foods

lists dietary sources of vitamins D and B.

3.2. Regulation of Estrogen Levels

3.2.1. Dietary Fiber

Fiber helps regulate estrogen levels in the body by binding it to estrogen in the intestines and helping to eliminate it from the body. This is important because high estrogen levels can stimulate the growth of endometrial tissue, worsening the symptoms of endometriosis. Research shows that a high-fiber diet is associated with lower levels of estrogen circulating in the body [3,4]. For example, women who consume higher amounts of fiber have been shown to have lower levels of estradiol, the main estrogen that plays a role in the development of endometriosis. Dietary fiber reduces circulating estrogen concentrations by 10 to 25% [5]. Fiber supports the health of your gut microbiota, which is crucial for your overall health and immune system [20]. A balanced gut microbiota can help reduce inflammation and improve immune function, which is important in managing endometriosis. Additionally, fiber improves intestinal motility, which helps prevent constipation [20,21]. Constipation can worsen pelvic pain and other symptoms of endometriosis, so regular bowel movements are important for women with this condition. Fiber, especially soluble fiber (found in fruits, vegetables, oats, flax seeds), may have anti-inflammatory effects [1]. Fermentation of fiber by gut bacteria leads to the production of short-chain fatty acids (SCFA), which have anti-inflammatory properties and may support gut health. And a high-fiber diet helps control weight by increasing satiety and regulating blood sugar levels [21]. Maintaining a healthy weight is important for women with endometriosis because excess weight can increase estrogen levels and worsen the symptoms of the disease [22]. Natural sources of fiber include vegetables, fruits, whole grains, legumes, seeds, and nuts [23].

3.2.2. Phytoestrogens

Phytoestrogens are plant compounds that have a chemical structure like estrogen which allows them to bind to estrogen receptors in the body. They can act either as agonists (enhancing the effects of estrogen) or antagonists (by blocking estrogen receptors) [23]. This allows phytoestrogens to help regulate estrogen levels, which is crucial in endometriosis because excess estrogen stimulates the growth of endometrial tissue [24]. The most well-known phytoestrogens are isoflavones, found mainly in soy and soy products. Isoflavones can bind to estrogen receptors, which can lead to a reduction in the activity of endogenous estrogens (the body’s own hormones) by competitively blocking the receptors. A diet rich in phytoestrogens influences the proper composition of the intestinal microflora, providing metabolites that influence the host’s physiology, hormonal balance, as well as the potential risk of endocrine disorders [24,25]. The gut microbiome influences the female reproductive endocrine system by interacting with estrogens, androgens, insulin, and other hormones [26]. On the other hand, increased estrogen secretion is a risk factor for endometriosis [26,27]. Phytoestrogens may have anti-inflammatory properties by modulating the immune response and inhibiting the production of pro-inflammatory cytokines [26]. Reducing inflammation is key in the treatment of endometriosis because inflammation is one of the main mechanisms leading to pain and the growth of endometrial tissue. Research suggests that consuming phytoestrogens may lead to a reduction in pain associated with endometriosis [27]. In one study, women with endometriosis who consumed isoflavones reported reduced pelvic pain and other symptoms associated with the disease. Women who consume a diet rich in phytoestrogens often report an overall improvement in quality of life, which may be the result of reduced pain symptoms and improved hormonal function [28].

Table 4. Dietary sources of phytoestrogens [28,29,30].

Legume Seeds	Cereals	Nuts and Grains	Fruits and Vegetables	Others
soy, chickpeas, lentils, peas, beans, edamame beans	wheat, oats, barley, rice	walnuts, almonds, sunflower seeds, flax seeds	broccoli, cauliflower, cabbage, carrots, apples, cherries, strawberries, pomegranates	red tea (rooibos) and green tea

shows the food sources of phytoestrogens.

3.3. Diet and Health Microbiota Intestines

The health of your gut microbiota is crucial to overall inflammation in your body. A diet rich in fiber and probiotics (fermented dairy products, pickles) can support a healthy intestinal microbiota, which, in turn, may reduce inflammation [26]. The gut microbiome plays an important role in overall health, and increasing evidence shows its association with the risk of developing endometriosis. The gut microbiome influences estrogen metabolism through a group of bacteria known as the estrobolome. The estrobolome produces enzymes that convert estrogen into active and inactive forms, thus regulating estrogen levels in the body. Disturbances in the composition of the microbiome may lead to abnormal estrogen metabolism, which may contribute to the development of endometriosis [24]. The gut microbiome plays a key role in regulating the immune system. A healthy microbiome supports an appropriate immune response, which is important in preventing the chronic inflammation that is characteristic of endometriosis [28]. Disturbances in the microbiome can lead to an abnormal immune response and increased production of pro-inflammatory cytokines [26,27,28,29,30]. Intestinal bacteria produce short-chain fatty acids (SCFA), which have anti-inflammatory properties and modulate the immune response [31]. A healthy microbiome influences the activity of macrophages and lymphocytes, which can help control the inflammation associated with endometriosis. Gut health is crucial to your overall health and well-being. Disturbances in the intestinal microbiome can lead to chronic inflammation, irritable bowel syndrome (IBS), and other intestinal disorders that may worsen the symptoms of endometriosis [32]. Studies have shown differences in the composition of the intestinal microbiome in women with endometriosis compared to healthy women [33]. Reduced microbiome diversity and changes in bacterial composition are often observed in women with endometriosis [26,27,28,29,30,31,32,33]. Changes in the gut microbiome may influence the severity of endometriosis symptoms, such as pelvic pain and digestive disorders. Eating vegetables, fruits, whole grains, and legumes supports a healthy gut microbiome. Supplementing with probiotics and consuming prebiotics (food for good bacteria) can support a healthy microbiome and improve the symptoms of endometriosis [22,31,32,33,34,35].

3.4. Avoiding Proinflammatory Foods

3.4.1. Saturated Fatty Acids

Saturated fatty acids, which are found mainly in animal products, can lead to increased inflammation in the body [8]. Increased inflammation is one of the mechanisms leading to the development and severity of endometriosis [24]. Saturated fatty acids can directly stimulate the expression of inflammatory genes by inducing activation of TLR4 receptors, activation of pro-inflammatory lipopolysaccharides, and stimulates the release of cytokines. Additionally, saturated fatty acids may also increase the risk of endometriosis by producing endogenous estrogen [36]. Research shows that a diet high in saturated fat can increase levels of inflammatory markers such as C-reactive protein (CRP) and TNF-α, IL-1, IL-6, and IL-8 proinflammatory cytokines [1,6]. Epidemiological studies suggest that women who consume more saturated fat may be at greater risk of developing endometriosis [4,5]. One study conducted by Nurses’ Health Study II found that high saturated fat intake was associated with a higher risk of endometriosis [37]. As mentioned, reducing dietary fat and increasing dietary fiber contributes to reducing circulating estrogen levels by approximately 10 to 25% [5]. Sources of saturated fats include red and processed meat, butter, fatty dairy products (cheese, cream), and coconut and palm oil [8].

3.4.2. Trans Fatty Acids

Trans fatty acids can increase levels of pro-inflammatory cytokines, such as IL-6 and TNF-α, which are thought to be involved in the pathogenesis of endometriosis [36]. A high intake of these types of fatty acids contributes to lower levels of good lipids such as HDL (good cholesterol), and both lead to chronic inflammation [8]. Studies have shown that women who consume high amounts of trans fatty acids have a higher risk of developing endometriosis [6,38]. It was found that women who consumed the most trans fats had a 48% higher risk of endometriosis compared to women who consumed the least [38]. Sources of trans fats: processed and fried foods, margarine and shortenings, snacks (chips, crackers), cakes, cookies, and other industrial baked goods [8].

3.4.3. Sugar and Refined Carbohydrates

Consumption of simple sugars can lead to rapid fluctuations in blood glucose levels, which, in turn, stimulates insulin secretion. Elevated levels of insulin and glucose in the blood can lead to inflammation, which is a key mechanism in the development of endometriosis [35]. Research indicates that high blood sugar levels are associated with elevated levels of inflammatory markers such as interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) [6]. Chronic inflammation can contribute to the growth and spread of endometrial tissue outside the uterus [24]. High levels of simple sugars in the diet can lead to insulin resistance, which can disturb the hormonal balance in the body. Insulin resistance can affect levels of estrogen and progesterone, hormones crucial to reproductive health [36]. Research shows that insulin resistance and elevated insulin levels can stimulate estrogen production in the ovaries and fatty tissue [37]. Excess estrogen may worsen the symptoms of endometriosis because estrogen stimulates the growth of endometrial tissue [23]. Consumption of large amounts of simple sugars may also negatively affect the composition of the intestinal microbiome [31,32,33,34,35]. Dysbiosis, or microbiome imbalance, can lead to increased intestinal permeability and chronic inflammation [26,27,28,29,30,31,32,33,34,35,36]. Research suggests that a diet high in simple sugars may lead to a reduction in the diversity of the gut microbiome and an increase in the population of pro-inflammatory bacteria. A healthy microbiome is key to regulating the immune system and inflammation, which may impact the development of endometriosis [4]. Simple sugars can lead to increased oxidative stress in the body, which is associated with cell and tissue damage. Oxidative stress is one of the mechanisms leading to chronic inflammation [15].

3.5. Specific Dietary Interventions

3.5.1. Gluten-Free Diet

A gluten-free diet eliminates gluten, a protein found mainly in wheat, rye, barley, and their derivatives. Gluten may be a factor provoking inflammation in people who are sensitive to this ingredient [2,7]. Reducing inflammation may provide relief from the symptoms of endometriosis, which are associated with chronic inflammation. Research is inconclusive about the direct effects of a gluten-free diet on endometriosis, but there is evidence that a gluten-free diet may reduce overall inflammation in the body [21]. This, in turn, may help relieve pain and other symptoms associated with endometriosis. People with endometriosis often experience gut health problems such as irritable bowel syndrome (IBS) or gut dysbiosis [22]. A gluten-free diet can help improve gut health by reducing inflammation, increasing the diversity of the gut microbiome, and reducing the symptoms of food intolerance [7,39]. Some research suggests that a gluten-free diet may be beneficial for people with irritable bowel syndrome (IBS), which often coexists with endometriosis [2,7]. Improving gut health can impact the overall health and well-being of endometriosis patients [21,39]. But a gluten-free diet should not be routinely used in patients with endometriosis unless the patient has been diagnosed with gluten-related diseases. Long-term use of a gluten-free diet is associated with the risk of nutritional deficiencies and the deterioration of intestinal microflora [40,41].

3.5.2. Mediterranean Diet

The main components of the Mediterranean diet are omega-3 acids, fiber, and antioxidants. Omega-3 fatty acids, found in fatty fish, nuts, and seeds, have anti-inflammatory properties. Increasing omega-3 intake may reduce the production of pro-inflammatory prostaglandins, alleviating the pain associated with endometriosis [7,20]. A diet high in fiber (vegetables, fruits, whole grains) can support gut health and reduce inflammation. Fiber helps regulate estrogen levels, which, in turn, may stimulate the development of endometriosis [20,42]. Antioxidants such as vitamin C, vitamin E, beta-carotene, resveratrol, selenium, and zinc can neutralize free radicals and reduce the oxidative stress that contributes to inflammation. A diet rich in fresh fruits, vegetables, and nuts may lead to reduced inflammation [4,43]. A Mediterranean diet, rich in fish, olive oil, vegetables, fruits, and whole grains is considered beneficial for women with endometriosis. It has been shown that it can reduce the risk of endometriosis and alleviate its symptoms thanks to its anti-inflammatory properties [7,20,42,43,44,45,46]. Oleocanthal, found in olive oil, is associated with cyclooxygenase inhibition through a mechanism like ibuprofen. Furthermore, olive oil and fish reduce markers of inflammation such as IL-6 and TNFα [45]. The results of Cirillo’s study indicate a clear trend toward an association between the Mediterranean dietary pattern and pain relief in endometriosis patients, including relief of chronic non-menstrual pelvic pain, dyspareunia, dysuria, and dysphasia [47]. The Mediterranean diet can be considered as a long-term strategy to support the treatment of endometriosis due to its health-promoting properties [48].

3.5.3. Low-FODMAP Diet

The low-FODMAP (fermentable oligo-, di-, monosaccharides and polyols) diet is a specialized diet that helps reduce symptoms associated with irritable bowel syndrome (IBS) by eliminating or limiting the consumption of certain carbohydrates that may be a source of digestive problems [49]. The low-FODMAP diet eliminates ingredients that can lead to inflammation in the intestines, which may be beneficial in the case of endometriosis, where chronic inflammation plays a key role [26]. People with endometriosis often experience intestinal problems such as irritable bowel syndrome [49]. A low-FODMAP diet can help reduce intestinal discomfort, which contributes to overall improvement in well-being [7,49]. The low-FODMAP diet requires the elimination of some ingredients, which may lead to vitamin, mineral, and fiber deficiencies, especially if it is not properly balanced. Currently, there is insufficient scientific research confirming the direct benefits of the low-FODMAP diet in the treatment of endometriosis. Most research focuses on irritable bowel syndrome [49,50,51,52,53]. Each person with endometriosis responds differently to different diets. An individual approach and monitoring of the body’s response to the low-FODMAP diet are important. For example, the low-FODMAP diet assumes the exclusion of lactose from dairy products. However, research emphasizes that the consumption of these products has a protective effect against the risk of endometriosis [54,55]. The low-FODMAP diet is an elimination diet; it is important that it is recommended to be used for no longer than 6–8 weeks. Its aim is to verify products that worsen intestinal symptoms. In addition to diet, holistic endometriosis management also includes regular treatment, adequate physical activity, stress reduction, and other health-supporting methods [7]. In summary, a low-FODMAP diet may be considered for endometriosis patients with gut problems, but caution and consultation with a health professional are recommended to ensure appropriate personalization and monitoring [48,52,56,57].

3.5.4. Anti-Inflammatory Diet

In women with endometriosis, increased concentrations of endothelial and inducible forms of nitric oxide synthase (eNOS and iNOS) are found in the peritoneal fluid. These are enzymes that lead to the production of nitric oxide (NO). In endometriosis, increased levels of eNOS and iNO are observed, which correlates with disorders of biological reproductive processes, e.g., ovulation, fertilization, implantation, and embryonic development. In endometriosis, it is also observed that increased eNOS activity results in higher levels of estrogen and progesterone. This disease involves impaired production of superoxide dismutase (SOD) and glutathione peroxidase (GPX), which may lead to oxidative damage. Induction of SOD by estrogen to overcome excessive oxidative stress contributes to the survival of endometriotic cells and protects them against apoptosis. Oxidative stress has been suggested to be an etiological factor in chronic pelvic pain, and antioxidant supplementation has been proven to reduce pain in patients with endometriosis [57]. Endometriosis is now considered an inflammatory disease; the probable culprit is ectopic divisions of the endometrium. After implantation, macrophages and neutrophils are the first to secrete and increase in proinflammatory, chemotactic, and angiogenic cytokines, including TNF-⍺, IL-1, IL-6, IL-8, and vascular endothelial growth factor (VEGF) [58]. A diet rich in anti-inflammatory nutrients, such as fruits, vegetables, oily fish (salmon, trout, mackerel), and healthy fats (olive oil, nuts, avocado), can lead to reduced inflammation by lowering the levels of pro-inflammatory cytokines in the body. The consequence of this is a reduction in the severity of endometriosis symptoms, such as pain and discomfort [41,57,58,59]. Some research suggests that an anti-inflammatory diet may help relieve the pain associated with endometriosis. Higher intakes of omega-3 fatty acids and magnesium lead to a reduction in the severity of menstrual pain and pain associated with endometriosis. Women struggling with endometriosis often suffer from depression and anxiety, associated with chronic pain and infertility, while an anti-inflammatory diet can improve the quality of life of patients by reducing the severity of symptoms and improving mental well-being [41,60,61]. An anti-inflammatory diet can also affect the body’s hormonal balance by regulating estrogen production. An anti-inflammatory diet, by reducing inflammation and hormonal regulation, may reduce the risk of infertility and ovarian cancer [2,7,21]. Consistent with general recommendations for healthy eating, an anti-inflammatory diet may be beneficial for patients with endometriosis as part of an overall disease management strategy [2,7,21]. Researchers suggest that anti-inflammatory dietary interventions may hold promise in preventing endometriosis [41]. Reducing animal protein intake and increasing plant protein intake; higher intake of high-fiber, low-glycemic carbohydrates; and higher non-heme iron intake may have a positive impact on reproductive health, with less risk of endometriosis [62], although high consumption of vegetables and fruits is often seen with some risk of exposure to pesticides. However, Garzia did not observe a significant relationship between the consumption of fruits and vegetables with high or low pesticide residue content and the risk of endometriosis [63]. Higher alcohol consumption and increased consumption of red meat and trans fats are associated with negative health effects and an increased risk of endometriosis [16,64,65,66,67]. Moreover, research results have shown that the intake of calcium, potassium, and vitamins E, B12, B2, B6, and C in the diet is inversely related to the risk of endometriosis [16,59,60], as is ensuring the proper status of vitamin D in the blood serum (i.e., through cutaneous synthesis, consumption of natural sources of vitamin, supplementation) [16,59,61]. In an anti-inflammatory diet, it is recommended to consume resveratrol (present in grapes, wine, berries, and nuts), turmeric, epigallocatechin-3-gallate (green and red tea), and quercetin (apples, berries, onions, cauliflower, and chili peppers) [62,68,69]. For example, in terms of anti-inflammatory effects, resveratrol treatment significantly reduced the expression of monocyte chemotactic protein-1, IL-6, IL-8, and normal T cells expressed and secreted in endometrial stromal cells, i.e., factors contributing to the inflammatory nature of endometriosis [70], and may also ameliorate endometriosis progression by reducing the expression of VEGF, TGF-β, and MMP-9 in endometrial stromal cells [71]. The potential role of brassica glucosinolates and isothiocyanates as anti-inflammatory compounds that may help reduce the symptoms of endometriosis was indicated [72]. A pro-inflammatory diet is significantly associated with the occurrence of endometriosis [16,40,73,74,75,76]. Endometriosis is considered an inflammatory and estrogen-dependent disease, and lifestyle changes may serve as a treatment factor for women suffering from endometriosis-related pelvic pain (e.g., dietary intervention; physical activity, e.g., yoga; sleep management; but also supplementation with exogenous melatonin and acupuncture) [77,78,79,80]. The anti-inflammatory diet is the second most frequently chosen dietary model (after the gluten-free diet) among women with endometriosis, which strongly emphasizes its importance in alleviating the symptoms of the disease [81]. And the anti-inflammatory effects of a healthy lifestyle can have a positive impact on pain perception [80,81,82] and lead to better quality of life [83,84,85]. The role of a dietitian in supporting the treatment of endometriosis is emphasized to alleviate symptoms such as intestinal problems, to avoid nutritional deficiencies, and to achieve normal body weight [86]. Following nutritional recommendations or taking supplements on your own may not yield satisfactory results [87] because women with endometriosis more often struggle with diseases of the upper gastrointestinal tract [88]; they are more exposed to deficiencies, including iron [89], vitamin D [5,17], and disturbed bacterial flora [26].

Table 5. The search results.

Ingredient/Factor	Mechanism of Action
Carbohydrates, proteins, and fats
Carbohydrates [6,36,58,67]	The higher risk of endometriosis from eating foods with a high glycemic index.
Increasing dietary fiber [4,5,36,45,62,68,75] and decreasing saturated fat [37,42,62,68,75]	Reduces circulating estrogen concentrations.
Proteins [6]	Replacing red meat with fish, shellfish, or eggs was found to reduce the risk of the disease.
High-fat diet [3,4,21]	Associated with oxidative stress and inflammation.
High consumption of trans fatty acids [4,5,37,42,62,67,68,75]	Increase proinflammatory markers such as Interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α).
Omega-3-PUFA [2,6,7,9,35,37,38,40,42,58,66,68]	Supplementation reduced lesion volume, IL-6, TNF-α, and VEGF concentrations in peritoneal fluid, COX-2 Ph-3-mitotic marker expression, adhesion formation, and collagen deposition.
Omega-6 [5,21,37,42,44,67,75]	Precursors of proinflammatory prostaglandins associated with increased pelvic pain in endometriosis.
Vitamins
Vitamin C [4,6,7,49,60,62,66,75]	Antioxidant properties resulting in pain relief and reducing the level of oxidative stress and inflammatory markers.
Vitamin E [4,6,49,60,62,66,75]	An antioxidant with additional antiangiogenic and anti-inflammatory effects, resulting in pain relief and reducing the level of oxidative stress and inflammatory markers.
Vitamin D [2,4,6,7,16,35,44,49,59,61,75,76]	A modulator of metabolic reactions and immune response. It decreased production of IL-17, IL-6, and IL-8 and increased the number of apoptotic cells.
Maintain good vitamin D levels [5,61,76]	Associated with a higher risk of suffering from endometriosis.
Vitamin A [6,32,51,62,66,68,75]	All-trans-retinoic acids (ATRA) contribute to hormonal changes and result in inhibitory effects on endometrial tissue.
B Vitamins [3,6,75]	All of them are involved in various cellular processes, including both catabolic and anabolic ones. [16,19] Pyridoxine (B6) increases inactive estrogen metabolism and supports the conversion of linoleic acid to the gamma-linolenic acid pathway, an essential component in the production of anti-inflammatory prostaglandins that can inhibit the growth of endometrial tissue [16].
Minerals
Zinc [6]	Increased migration, increased invasiveness, and increased resistance of endometrial cells to apoptosis in endometriosis are the result of epithelial–mesenchymal transition (EMT), a part of the regulation process in which transcription factors containing zinc in their structure play a role.
Copper [6]	Cu/Zn-SOD type plays a major role in antioxidant protection in patients with endometriosis. Additionally, by acting as a metalloestrogen, Cu can influence estrogen-dependent conditions.
Iron [6,7,88];	A key molecule in the process of DNA synthesis and respiratory chain reactions. It may also contribute to the formation of ROS as a result of the transformation of Fenton reaction products. Women with endometriosis are at a higher risk of developing iron deficiency than those without endometriosis.
Selenium [6]	It is an essential component of selenoproteins, glutathione and peroxidase, and it is involved in the regulation of oxidative stress.
High potassium intake [3,6]	Associated with a reduced risk of endometriosis due to the role of this ion in the immune system
Manganese [6]	A component of the Mn-SOD involved in neutralizing free radicals. This enzyme is under the influence of elevated levels of tumor-necrosis factor-alpha (TNF-α), the factor contributing to the maintenance of the inflammatory state in endometriosis.
Dietary ingredients/treatment
Phytoestrogens [6,21,24,75]	Influences the body’s production of natural estrogen, either by modulating the activity of enzymes involved in estrogen metabolism or by affecting the overall hormonal balance.
Resveratrol [7,9,44,66,70,71]	A pro-apoptotic function and inhibitory effect on cell proliferation and invasive growth. It reduces the expression of MCP-1, IL-6, and IL-8 and the regulation of pathways linked to oxidative stress, inflam-mation, cyclooxygenase-2 (COX-2), and Sirtuin 1.
Herbs (thyme, oregano, basil, rosemary, mint, sage, curcuma [5,21,36,66] dill, cinnamon, parsley, clove, lemon grass, nutmeg, ginger, fenugreek, pepper, nd chili pepper [7])	Anti-inflammatory and anticancer properties. It reduces the concentration of estrogens, TNF alpha, and interleukin mediators, accelerates cellular apoptosis, and inhibits angiogenesis.
Melatonin [5,80]	Inhibits estradiol-induced epithelial–mesenchymal transition and migration of endometrial epithelial cells.
Caffeic acid [7,52,69,75,77]	Reduces oxidative stress, which can alleviate complications from endometriosis.
Red meat [4,5,7,20,37,40,45,52,66,67,68,73]	Associated with high levels of estradiol, estrone sulfate, and proinflammatory markers.
Dairy Food [4,7,45,52,54,55,73,78]	A high consumption of calcium-rich dairy products may reduce inflammatory and oxidative stress by decreasinginflammatory factors such as tumor necrosis factor-a (TNF-a), reactive oxygen species, and IL-6.
Increase fruit consumption [5,42,62,66,68,75,78,83]	Antioxidants reduce inflammatory processes.
Supplementation with vitamin D and omega-3-PUFA [10,62,75]	Leads to significant changes in pelvic pain (i.e., pain reduction).
Vitamin D treatment [17]	Can downregulate key molecules involved in proliferation, invasion, angiogenesis, and inflammation in endometriotic cells.
Seawead [4]	Estrogen-modulating activity.
Polyphenols [4,27,63,64,72]	Anti-inflammatory properties.
Alcohol consumption [2,21,75]	Worsening of endometriosis symptoms.
Tofu (processed soybean curd) consumption [25]	Associated with significantly decreased odds of endometriosis. Isoflavones have an antioxidant property.
Carrots (contain high levels of antioxidant carotenoids) [25]	May reduce the inflammatory responses that occur in individuals with endometriosis.
Maintain a healthy gut microbiome [31,34,40]	The gut microbiota have the ability to regulate circulating estrogen levels via the estrobolome, which is defined as the collection of genes encoding estrogen-metabolizing enzymes, specifically in the gut microbiome.
N-acetylcysteine supplementation [44]	Can effectively reduce inflammation and alleviate endometriosis.
Nutritional models
The Mediterranean diet (MD) [7,20,35,38,46,47,48,49,63,81]	Improve the general well-being of women with endometriosis and reduced pain, dyspareunia, dysmenorrhea, and dyschezia via anti-inflammatory properties.
Vegetarian/Vegan diet [4,43]	Lead to increased levels of sex hormone-binding globulin (SHBG) and decreased estrogen levels in women. This is followed by a decrease in estrogenic stimulation of the endometrium and a reduction in the proliferation of prostaglandin-producing tissues.
Low-nickel diet [7,35,49,51]	Might significantly decrease all gastro, extraintestinal, andgynecological symptoms. Might also decrease pain, dyspareunia, and dysmenorrhea.
Low-FODMAP diet [2,7,21,35,40,49,52,84,86]	Beneficial for patients with endometriosis and gut symptoms.
Gluten-free diet [2,7,21,35,36,39,40,41,49,52,81]	May alleviate pain due to the obstruction of gluten-mediated im-munomodulation and the inflammatory response by inflecting the cytokine system.
Anti-inflammatory diet [34,38,40,43,57,63,76] and antioxidants (like vitamins C and E, selenium, and zinc) [4,16]	Antioxidants may affect the endometriosis operating system by upsetting the balance between ROS production and antioxidant levels. They are associated with cell proliferation in response to chronic inflammation and reactive oxygen species (ROS) in endometriosis. Those which may play an essential role in cell development and proliferation have reduced endometriosis.

summarizes the main results of the literature review.

4. Conclusions

Diet can significantly impact the course of endometriosis by helping to reduce inflammation and regulate hormone levels. Dietary recommendations include increasing intake of omega-3 fatty acids, fiber, and antioxidants, and avoiding pro-inflammatory foods such as trans fats and sugar. Additionally, some specific diets, such as the Mediterranean or gluten-free diet, may be particularly beneficial. It is worth consulting a dietitian and doctor to develop an individual nutritional plan tailored to the needs of every woman suffering from endometriosis.

5. Limitations

The authors agree that the weaknesses of the above review include the lack of statistical evaluation and reliability of the cited studies. This review summarizes the most common dietary trends in the treatment of endometriosis over the last five years. However, it only refers to one scientific database.