Changing lifestyle and dietary pattern towards sedentary lifestyle and poor nutrition can lead to insulin resistance. Compared to people with normal physiological condition, it is perhaps the most important aspect of IR, the worsening of the disease condition, and a significant increase in mortality. One of the disorders in which IR is a key part of its pathological mechanism is PCOS. The mechanism and main cause of this disorder have not been explained in general, but considering the results of scientific studies, IR, oxidative stress and inflammation are among the first-degree defendants. The aim of this investigation, was to evaluate the EA effects on blood glucose, insulin resistance, lipid profile, oxidative stress status, inflammatory factors, sex hormone levels and anti-mullerian hormone in women with PCOS. After 8 weeks, supplementation with EA, significantly decreased the FBS, IR. Also, at the end of the study, reduction of TC, TG and LDL changes in the intervention group was significant.
Some scientific studies have reported an increase in insulin due to an increase in androgens, and some scientific sources have assumed the exact opposite of this equation. However, a decrease in insulin levels and, consequently, a decrease in IR has reduced androgens and better ovarian function. Elevated insulin levels usually cause hyperlipidemia in women with this syndrome. Continuity of these conditions and lack of improvement in biochemical factors can lead to cardiovascular disease. According to the World Health Organization, women with PCOS are more likely to develop myocardial infarction. It seems that the core of all these disorders is IR. The function of genes involved in the secretion and modulation of insulin role, such as genes associated with Sirtuin1 and glucose transporter 2 (Glut2), as well as their effect on insulin signaling, such as glucose transporter 4 (Glut4) in muscle and peroxisome proliferator-activated receptor-gamma (PPARγ) in fat cells, is mainly significantly influenced by dietary polyphenols. EA as a polyphenol and strong antioxidant, has not been studied as a dietary supplement in women with PCOS (according to a search on a scientific database), but its helpful effects on glycemic status have been shown in other metabolic disorders. The clinical trial study of Babaeian et al., that conducted on patients with type 2 diabetes, intervention group drank 240 ml unsweetened pomegranate juice daily. The results of the study showed a significant decrease in insulin resistance at the end of the study, whereas no significant changes were found for serum glucose in this group. Low dose of EA in pomegranate juice or short study time for this dose, may be reasons for the lack of significant effect on glycemic indexes. Esmaeilinezhad et al. investigated the effect of pomegranate juice on cardiovascular risk factors in women with PCOS. Participants received daily pomegranate juice or placebo beverage. Daily consumption of pomegranate juice improved the metabolic outcomes of TG, LDL, HDL and TC, in patients. The possible mechanism of EA that lowers blood cholesterol may be due to its effect on reducing absorption and increasing cholesterol excretion through the feces. The effect of this polyphenol on important and key enzymes in cholesterol metabolism, including hydroxy-methyl-glutaryl-CoA (HMG-COA) reductase and Acyltransferase, has also been reported in laboratory and clinical studies. EA, on the other hand, increases the persistence of beneficial bacteria in the gastrointestinal tract by reducing oxidative stress products, and thus reducing the excess plasma fat by beneficial bacteria can be helpful[26, 27]. On the other hand, the condition that worsens IR, exacerbation of oxidative stress status and increased inflammation in these patients. After glycation reactions and formation of advanced glycation end products (AGEs), production of ROS occurs rapidly increased. This reaction can damage insulin-secreting cells in the pancreas. According to the results of studies, receiving polyphenols can increase the prescription of PPAR-γ and in this way, they can help reduce the chronic complications of PCOS. By summarizing the cellular, experimental, and clinical studies, it can be concluded that relationship between IR and oxidative stress is mutual. In the meantime, inflammation can make both sides of the equation worse. The results of our study indicated that EA significantly improved the stress oxidative index and decreased the inflammatory factors. Abnormalities in oxidative stress index in women with PCOS were reported in the meta-analysis study of Murri et al. Also, the results of many studies showed high biomarker such as MDA and low indicators of antioxidant system such as TAC in these patients. Goudarzi et al. investigated the protective effect of EA on sodium arsenic-induced neurotoxicity in rats. They observed that EA administration significantly increased MDA levels, IL1β levels and TNF α levels in the brain compared to the control group. EA administration also increased TAC levels compared to the control group. DNA damage and subsequent harmful genetic changes occur as a result of free radical attacks on DNA. This can lead to DNA methylation and silence of tumor suppressor genes. Therefore, oxidative stress can be a factor in worsening PCOS and even increasing the risk of other metabolic diseases such as cancer in women with this syndrome. One of the pre-inflammatory mediators is nitric oxide (NO), which can cause damage and inflammation due to overproduction. Increased synthesis of the NO synthase enzyme, which is present in macrophages, is increased in PCOS, which can lead to inflammation and increased insulin resistance. In cellular and animal studies, EA has been reported to reduce NO production. Also, one of the enzymes produced by pre-inflammatory cytokines is the Cyclooxygenase 2 (COX-2) enzyme, which in itself accelerates cascading reactions and releases large amounts of Prostaglandin E2 (PGE2) into the inflamed tissue. However, by inhibiting COX-2 production, inflammation can be reduced. The inhibitory effects of EA on PGE2 production have been reported. Pomegranate-derived polyphenols have also reduced COX-2 production from macrophage cells.
Also, EA supplementation resulted in a statistically significant decrease in total testosterone, PRL and AMH hormone levels compared with the beginning of the study. Changes in the mean of the FSH and LH levels at the end of the study were not significant. Hyperandrogenism women usually occur after an increase in insulin. Excessive increase in sex hormones impairs ovulation and increases AMH. Together, these biochemical symptoms will be a prognosis for PCOS. Taking into account the above mechanism and the results of animal and clinical studies, the normalization of the ovulation cycle can be achieved by increasing insulin sensitivity and ultimately reducing sex hormones and lowering AMH. One of the most effective factors in reducing IR is the use of plant polyphenols. So far, no clinical studies have examined the effects of EA polyphenol on mentioned factors, but some micronutrients have been studied with antioxidant properties. The results of Shokrpour et al. study indicated that receiving CoQ10 in women with PCOS significantly decreased the level of AMH. In this clinical trial, 30 women with PCOS consumed CoQ10 pills 100 mg daily for 3 months. Also, in AbdulameerYahya et al. study, taking the vitamin D and CoQ10 oral supplement in PCOS patients ameliorated the hormonal profile, oxidative marker, and ovulation outcome. Their results showed that these antioxidants significantly decreased the LH and AMH after eight weeks. Also, studies that have examined the effects of IR-reducing drugs such as metformin in women with this syndrome have also reported a significant reduction in sex hormones such as LH, testosterone and AMH at the end of the study. This clinical study, like other studies, can have strengths and weaknesses. One of the strengths of this study is that for the first time the effect of pure supplement of EA was investigated in women with PCOS. Also, the design of this study as a double-blind randomized clinical trial that had parallel groups, making the results of this study remarkable. It is also important to control confounder factors such as weight, physical activity, and food intake in studies that conducted on metabolic diseases, which was done in this research. However, due to the low budget and the limited number of participants and the duration of the intervention, the results of this study have been statistically analyzed, it should be noted that in order to draw clinical conclusions and examine the clinical effects, it is necessary to conduct studies with a larger number of participants and intervention period.