The effects of pomegranate peel added bread on anthropometric measurements, metabolic and oxidative parameters in individuals with type 2 diabetes: a double-blind, randomized, placebo-controlled study

Pomegranate: A Comprehensive Review of Functional Components, Health Benefits, Processing, Food Applications, and Food Safety

Pomegranate gained widespread attention for its potential "medicine and food homology" properties. This review aims to elucidate the main health benefits of the functional components of pomegranate and to summarize its processing and application. It explores current research limitations and proposes potential research directions. Pomegranate juice is rich in punicalagin, ellagic acid, and cyanidin-3-O-glucoside. The gut microbiota metabolites of these compounds could exert biological effects through Nrf2/HO-1, miR-126/VCAM-1, Akt/IKK/NF-κB, and SIRT1/PGC-1α signaling pathways. The pomegranate peel also contains these components, which can be extracted by microwave-assisted extraction, ultrasonic-assisted extraction, and pressurized liquid extraction and then used in food additives or functional foods. Furthermore, safety concerns exist due to variations in extraction methods and potential food-drug interactions. This paper emphasizes the importance of developing standardized extraction methods and clear intake dosage guidelines, which will lay the foundation for the application of pomegranate in the food industry.

Lack of Efficacy of Pomegranate Supplementation on Insulin Resistance and Sensitivity: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The objective of this study is to assess the impact of pomegranate supplements on insulin resistance (IR) and insulin sensitivity through a systematic review and meta-analysis of randomized controlled trials (RCTs). Additionally, we aim to analyze the differences in efficacy among various pomegranate extracts and the sensitivity of different diseases to pomegranate supplementation. We conducted searches in PubMed, Embase, Web of Science, and Cochrane Library up to October 30, 2023, for relevant studies published in English. The treatment group required the intake of pomegranate extract for a minimum of 4 weeks, with no restrictions on the extract type. The control group received a placebo or a treatment excluding pomegranate extract. The primary outcome was homeostatic model assessment for insulin resistance (HOMA-IR) and fasting insulin (FI), and the secondary outcome was quantitative insulin sensitivity check index (QUICKI). RoB 2 was used to assess the risk of bias in the original studies. We pre-specified subgroup analyses based on types of intervention, intervention duration, health condition, and intervention dose. Sensitivity analysis was conducted to validate result stability, utilizing Begg's test and Egger's test for publication bias. Data synthesis and analysis were performed using Stata 15.1 software. This study included a total of 15 RCTs with 673 participants conducted in 7 countries. Risk of bias results indicated an overall low risk of bias of the articles. Participants included healthy individuals, overweight and obese individuals, non-alcoholic fatty liver disease (NAFLD) patients, type 2 diabetes (T2DM) patients, polycystic ovary syndrome (PCOS) patients, metabolic syndrome (MS) patients, and individuals with hyperlipidemia. Pomegranate extract variations included pomegranate juice (PJ), pomegranate seed oil (PSO) capsule, pomegranate/pomegranate peel (PP) extract capsule, and pomegranate peel-added bread. The control groups primarily received placebo treatments with varying dosage and frequency. No adverse reactions were reported in any of the studies. The summary results showed that compared to the control groups, pomegranate extract had no significant impact on improving HOMA-IR levels in participants (WMD = -0.03, 95%CI: -0.37 to 0.31, and p = 0.851) and FI (WMD = -0.03, 95%CI: -0.42 to 0.36, and p = 0.862). Additionally, there was no significant advantage of pomegranate extract on QUICKI changes in T2DM and PCOS patients (WMD = 0.00, 95%CI: 0.00 to 0.01, and p = 0.002). Subgroup analysis results indicated that pomegranate extract could improve HOMA-IR levels in PCOS patients (WMD = -0.42, 95%CI: -0.54 to -0.29, and p < 0.001) and FI levels in T2DM, PCOS, and NAFLD patients. Our results indicate that pomegranate extract only improves HOMA-IR and FI levels in PCOS patients and FI levels in T2DM and NAFLD patients. No significant difference has been found for HOMA-IR, FI, or QUICKI in other metabolic diseases. The current evidence suggests that we should interpret the value of pomegranate extract in regulating IR and sensitivity cautiously. In the future, there is a need for more rigorously designed RCTs to specifically evaluate the impact of pomegranate supplementation on insulin sensitivity in patients with NAFLD, PCOS, and T2DM.

The effects of pomegranate consumption on blood pressure in adults: A systematic review and meta-analysis

Considering the main component of cardiovascular disease and due to the high prevalence of hypertension, controlling blood pressure is required in individuals with various health conditions. Randomized clinical trials (RCTs) which studied the effects of pomegranate consumption on blood pressure have shown inconsistent findings. As a result, we intended to assess the effects of pomegranate consumption on systolic (SBP) and diastolic (DBP) blood pressure in adults. Systematic literature searches up to January 2024 were carried out using electronic databases, including PubMed, Web of Science, and Scopus, to identify eligible RCTs assessing the effects of pomegranate on blood pressure as an outcome. All the individuals who took part in our research were adults who consumed pomegranate in different forms as part of the study intervention. Heterogeneity tests of the selected trials were performed using the I2 statistic. Random effects models were assessed based on the heterogeneity tests, and pooled data were determined as the weighted mean difference (WMD) with a 95% confidence interval (CI). Of 2315 records, 22 eligible RCTs were included in the current study. Our meta-analysis of the pooled findings showed that pomegranate consumption significantly reduced SBP (WMD: -7.87 mmHg; 95% CI: -10.34 to -5.39; p < 0.001) and DBP (WMD: -3.23 mmHg; 95% CI: -5.37 to -1.09; p = 0.003). Individuals with baseline SBP > 130 mmHg had a significantly greater reduction in SBP compared to individuals with baseline SBP < 130 mmHg. Also, there was a high level of heterogeneity among studies (SBP: I2 = 90.0% and DBP: I2 = 91.8%). Overall, the results demonstrated that pomegranate consumption lowered SBP and DBP in adults. Although our results suggest that pomegranate juice may be effective in reducing blood pressure in the pooled data, further high-quality studies are needed to demonstrate the clinical efficacy of pomegranate consumption.