Effects of pomegranate juice in circulating parameters, cytokines, and oxidative stress markers in endurance-based athletes: A randomized controlled trial

The power of Punica granatum: A natural remedy for oxidative stress and inflammation; a narrative review

ETHNOPHARMACOLOGICAL RELEVANCE

Pomegranate 'Punica granatum' offers multiple health benefits, including managing hypertension, dyslipidemia, hyperglycemia, insulin resistance, and enhancing wound healing and infection resistance, thanks to its potent antioxidant and anti-inflammatory properties. It has been symbolized by life, health, femininity, fecundity, and spirituality.

AIM OF THE STUDY

Although laboratory and animal studies have been conducted on the healing effects of pomegranate, there needs to be a comprehensive review on its anti-oxidative and anti-inflammatory effects in chronic disorders. We aim to provide a comprehensive review of these effects based on in-vitro, in-vivo, and clinical studies conducted in managing various disorders.

MATERIALS AND METHODS

A comprehensive search of in-vitro, in-vivo, and clinical findings of pomegranate and its derivatives focusing on the highly qualified original studies and systematic reviews are carried out in valid international web databases, including Web of Science, PubMed, Scopus, and Cochrane Library.

RESULTS

Relevant studies have demonstrated that pomegranate and its derivatives can modulate the expression and activity of several genes, enzymes, and receptors through influencing oxidative stress and inflammation pathways. Different parts of pomegranate; roots, bark, blossoms, fruits, and leaves contain various bioactive compounds, such as polyphenols, flavonoids, anthocyanins, and ellagitannins, that have preventive and therapeutic effects against many disorders such as cardiovascular diseases, diabetes, neurological diseases, and cancers without any serious adverse effects.

CONCLUSIONS

Most recent scientific evidence indicates that all parts of the pomegranate can be helpful in treating a wide range of chronic disorders due to its anti-oxidative and anti-inflammatory activities. Since the safety of pomegranate fruit, juice, and extracts is established, further investigations can be designed by targeting its active antioxidant and anti-inflammatory constituents to discover new drugs.

The Influence of a Polyphenol-Rich Red Berry Fruit Juice on Recovery Process and Leg Strength Capacity after Six Days of Intensive Endurance Exercise in Recreational Endurance Athletes

BACKGROUND

Various nutritional strategies are increasingly used in sports to reduce oxidative stress and promote recovery. Chokeberry is rich in polyphenols and can reduce oxidative stress. Consequently, chokeberry juices and mixed juices with chokeberry content are increasingly used in sports. However, the data are very limited. Therefore, this study investigates the effects of the short-term supplementation of a red fruit juice drink with chokeberry content or a placebo on muscle damage, oxidative status, and leg strength during a six-day intense endurance protocol.

METHODS

Eighteen recreational endurance athletes participated in a cross-over high intensity interval training (HIIT) design, receiving either juice or a placebo. Baseline and post-exercise assessments included blood samples, anthropometric data, and leg strength measurements.

RESULTS

A significant increase was measured in muscle damage following the endurance protocol in all participants (∆ CK juice: 117.12 ± 191.75 U/L, ∆ CK placebo: 164.35 ± 267.00 U/L; p = 0.001, η2 = 0.17). No group effects were detected in exercise-induced muscle damage (p = 0.371, η2 = 0.010) and oxidative status (p = 0.632, η2 = 0.000). The reduction in strength was stronger in the placebo group, but group effects are missing statistical significance (∆ e1RM juice: 1.34 ± 9.26 kg, ∆ e1RM placebo: -3.33 ± 11.49 kg; p = 0.988, η2 = 0.000).

CONCLUSION

Although a reduction in strength can be interpreted for the placebo treatment, no statistically significant influence of chokeberry could be determined. It appears that potential effects may only occur with prolonged application and a higher content of polyphenols, but further research is needed to confirm this.

The effects of pomegranate consumption on liver function enzymes in adults: A systematic review and meta-analysis

BACKGROUND

We performed a systematic review and meta-analysis of all published clinical trial studies to provide a more accurate estimation of pomegranate effects on liver enzymes in different clinical conditions.

METHODS

A systematic literature search was carried out using electronic databases, including PubMed, Web of Science, and Scopus, up to March 2023 to identify eligible randomized clinical trials (RCTs) evaluating the effect of pomegranate consumption on liver function enzymes. 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 with a 95% confidence interval.

RESULTS

Out of 3811 records, 9 eligible RCTs were included in the current study. However, there are limitations in the included studies, which can be mentioned in the dose, duration, and type of interventions that are different among the studies, as well as the small number of included studies. All this causes heterogeneity among studies and this heterogeneity limits the consistency of the results. Our meta-analysis showed that pomegranate intake had a significant effect on lowering aspartate aminotransferase (AST) levels in long-term intervention (> 8 weeks), obese (BMI≥30) individuals, or patients with metabolic disorders. Furthermore, results showed a significant decrease in alanine aminotransferase (ALT) levels in the long-term intervention (> 8 weeks) or in patients with metabolic disorders following the pomegranate intake. Combined results from the random-effects model indicated a significant reduction in gamma-glutamyl transferase (GGT) levels (WMD: -5.43 IU/L 95% CI: -7.78 to -3.08; p < 0.001;) following the pomegranate intake. The results of Egger's test mentioned a significant publication bias for the trials examining the effect of pomegranate intake on AST (p = 0.007) and ALT (p = 0.036).

CONCLUSION

Our results suggest that long-term pomegranate intake may be effective in ameliorating liver enzymes in adults with obesity and metabolic disorders who are more likely to have elevated baseline liver enzymes due to some degree of liver injury or tissue damage. However, some studies failed to conduct independent biochemical characterization of the product used, including the presence and quantity of polyphenols, antioxidants, and proanthocyanidins.

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

BACKGROUND AND AIM

Epidemiologic studies have shown that type 2 diabetes (T2D) is more prevalent worldwide; therefore, improving glycemic indices to prevent or control T2D is vital. Randomized controlled trials (RCTs) on the effects of pomegranate consumption on glycemic indices have shown inconsistent results. Therefore, we aim to evaluate the impact of pomegranate consumption on fasting blood glucose (FBG), fasting insulin, hemoglobin A1c (HbA1c), and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) in adults.

METHODS

A systematic literature search was performed using electronic databases, including PubMed, Web of Science, and Scopus, up to May 2023 to identify eligible RCTs evaluating the effect of pomegranate consumption on glycemic indices. Heterogeneity tests of the included 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 with a 95 % confidence interval.

RESULTS

Of 1999 records, 32 eligible RCTs were included in the current study. Our meta-analysis of the pooled findings showed that pomegranate consumption significantly reduced FBG (WMD: -2.22 mg/dL; 95 % CI: -3.95 to -0.50; p = 0.012), fasting insulin (WMD: -1.06 μU/ml; 95%CI: -1.79 to -0.33; p = 0.004), HbA1c (WMD: -0.22 %; 95% CI: -0.43 to -0.01; p = 0.037), and HOMA-IR (WMD: -0.30; 95%CI: -0.61 to -0.00; p = 0.046).

CONCLUSION

Overall, the results demonstrated that pomegranate consumption benefits glycemic indices in adults. However, further research with long-term interventions is required.

PROSPERO REGISTRATION CODE

CRD42023422780.

Crosstalk between dietary pomegranate and gut microbiota: evidence of health benefits

Gut microbiota (GM) is an invisible organ that plays an important role in human health. Increasing evidence suggests that polyphenols in pomegranate (punicalagin, PU) could serve as prebiotics to modulate the composition and function of GM. In turn, GM transform PU into bioactive metabolites such as ellagic acid (EA) and urolithin (Uro). In this review, the interplay between pomegranate and GM is thoroughly described by unveiling a dialog in which both actors seem to affect each other's roles. In a first dialog, the influence of bioactive compounds from pomegranate on GM is described. The second act shows how the GM biotransform pomegranate phenolics into Uro. Finally, the health benefits of Uro and that related molecular mechanism are summarized and discussed. Intake of pomegranate promotes beneficial bacteria in GM (e.g. Lactobacillus spp., Bifidobacterium spp.) while reducing the growth of harmful bacteria (e.g. Bacteroides fragilis group, Clostridia). Akkermansia muciniphila, and Gordonibacter spp., among others, biotransform PU and EA into Uro. Uro contributes to strengthening intestinal barrier and reducing inflammatory processes. Yet, Uro production varies greatly among individuals and depend on GM composition. Uro-producing bacteria and precise metabolic pathways need to be further elucidated therefore contributing to personalized and precision nutrition.

Reporting of adverse effects of pomegranate in clinical studies: a systematic review

OBJECTIVES

Numerous studies have shown the pharmacological effects of pomegranate, such as: anti-cancer, cholesterol-lowering, anti-diabetic, and antihypertensive features. Pomegranate consumption has also revealed some adverse effects. This systematic review aimed to explore the adverse effects of pomegranate reported in clinical studies.

CONTENT

The keywords "pomegranate", "Punica granatum", "side effect", "clinical trial", and "case report or case series" were searched for in valid databases. Reports about adverse effects of pomegranate were also collected from several international registries.

SUMMARY

This systematic review included a total of 66 clinical articles. Eleven articles have reported side effects of pomegranate. Twenty-one articles have recorded no side effects in the pomegranate group while 34 articles have not mentioned any side effects for this plant. The study also included 7 case report studies. The most common side effects included gastrointestinal problems, flu-like symptoms, and urinary problems. In case report studies, the most significant reported side effect was allergic reaction.

OUTLOOK

In summary, pomegranate and its extract seem to be safe according to the reported adverse effects. Meanwhile, conducting more robust controlled trials with pomegranate products and documentation of any probable side effect is warranted.

Acoustic streaming enabled moderate swimming exercise reduces neurodegeneration in C. elegans

Regular physical exercise has been shown to delay and alleviate neurodegenerative diseases. Yet, optimum physical exercise conditions that provide neuronal protection and exercise-related factors remain poorly understood. Here, we create an Acoustic Gym on a chip through the surface acoustic wave (SAW) microfluidic technology to precisely control the duration and intensity of swimming exercise of model organisms. We find that precisely dosed swimming exercise enabled by acoustic streaming decreases neuronal loss in two different neurodegenerative disease models of Caenorhabditis elegans, a Parkinson's disease model and a tauopathy model. These findings highlight the importance of optimum exercise conditions for effective neuronal protection, a key characteristic of healthy aging in the elderly population. This SAW device also paves avenues for screening for compounds that can enhance or replace the beneficial effects of exercise and for identifying drug targets for treating neurodegenerative diseases.

Curcumin-Added Whey Protein Positively Modulates Skeletal Muscle Inflammation and Oxidative Damage after Exhaustive Exercise

(1) Background: Exhaustive exercise can induce muscle damage. The consumption of nutritional compounds with the ability to positively influence the oxidative balance and an exacerbated inflammatory process has been previously studied. However, little is known about the nutritional value of curcumin (CCM) when mixed with whey protein concentrate (WPC). This study was developed to evaluate the effect of CCM-added WPC on inflammatory and oxidative process control and histopathological consequences in muscle tissue submitted to an exhaustive swimming test (ET). (2) Methods: 48 animals were randomly allocated to six groups (n = 8). An ET was performed 4 weeks after the start of the diet and animals were euthanized 24 h post ET. (3) Results: WPC + CCM and CCM groups reduced IL-6 and increased IL-10 expression in muscle tissue. CCM reduced carbonyl protein after ET compared to standard AIN-93M ET and WPC + CCM ET diets. Higher nitric oxide concentrations were observed in animals that consumed WPC + CCM and CCM. Consumption of WPC + CCM or isolated CCM reduced areas of inflammatory infiltrate and fibrotic tissue in the muscle. (4) Conclusions: WPC + CCM and isolated CCM contribute to the reduction in inflammation and oxidative damage caused by the exhaustive swimming test.

Effects of Functional Phenolics Dietary Supplementation on Athletes' Performance and Recovery: A Review

In recent years, many efforts have been made to identify micronutrients or nutritional strategies capable of preventing, or at least, attenuating, exercise-induced muscle damage and oxidative stress, and improving athlete performance. The reason is that most exercises induce various changes in mitochondria and cellular cytosol that lead to the generation of reactive species and free radicals whose accumulation can be harmful to human health. Among them, supplementation with phenolic compounds seems to be a promising approach since their chemical structure, composed of catechol, pyrogallol, and methoxy groups, gives them remarkable health-promoting properties, such as the ability to suppress inflammatory processes, counteract oxidative damage, boost the immune system, and thus, reduce muscle soreness and accelerate recovery. Phenolic compounds have also already been shown to be effective in improving temporal performance and reducing psychological stress and fatigue. Therefore, the aim of this review is to summarize and discuss the current knowledge on the effects of dietary phenolics on physical performance and recovery in athletes and sports practitioners. Overall, the reports show that phenolics exert important benefits on exercise-induced muscle damage as well as play a biological/physiological role in improving physical performance.

Pomegranate (Punica granatum L.) and Metabolic Syndrome Risk Factors and Outcomes: A Systematic Review of Clinical Studies

Pomegranate (Punica granatum L.) can be considered a multipurpose medicinal and dietary plant due to its anti-inflammatory and antioxidant actions. Pomegranate can be used to prevent or treat metabolic syndrome (MetS) risk factors. Although previously published reviews addressed the effects of pomegranate on different diseases, there is no systematic review that exclusively focuses on clinical trials related to all MetS-related risk factors. In view of this limitation, the objective of this up-to-date, comprehensive, and systematic review is to critically evaluate the potential of pomegranate (P. granatum) on various MetS risk factors on the basis of clinical studies. PubMed, EMBASE, MEDLINE, Google Scholar, COCHRANE, and Clinical Trials.gov databases were searched on 15 October 2021. The Preferred Reporting Items for a Systematic Review and Meta-Analysis guidelines were followed, and the bias risk evaluation was performed according to the Cochrane Handbook for Systematic Reviews of Interventions. We identified 5683 studies in the databases. After removing the duplicates, 3418 studies remained. Of these, 147 studies met the eligibility criteria, and finally, only 20 were included in the qualitative analysis. The included studies suggest that pomegranate can be beneficial to reduce body weight, blood pressure, glycemia, triglycerides, total cholesterol, and low-density lipoprotein cholesterol. Moreover, it can augment high-density lipoprotein cholesterol levels and improve insulin resistance. Although relevant effects were observed, additional well-designed clinical trials are needed to determine the correct formulations and doses to be used to prevent or treat MetS components.

Effects of Punica granatum Fruit (a Super Food) Juice on Human Health

Background:

Pomegranate (Punica granatum L.), one of the oldest known edible fruits, is nowadays broadly consumed throughout the world. Its fruits and seed are rich in many bioactive compounds, as polyphenols, and the scientific interest in this plant has been constantly growing in recent years.

Introduction:

Pomegranate fruit and its juice have been shown to have health benefits relating to their antioxidant and anti-inflammatory properties. They are used in alternative medicine as adaptogens and ergogens protecting against many neurological, cardiovascular, gastrointestinal, liver, and skin disorders.

Methods:

Given the amount of evidence, this narrative review does not seek to supply a comprehensive summary of all study findings, but rather focuses on human clinical trials related the last five years. In this regard, we have performed a check in MEDLINE, and clinical trials presented in this time are summarized.

Result:

The use of pomegranate as table fruit or juice, rich source of polyphenols, can so be recommended in human nutrition for its benefic properties. The consumption of pomegranate fruit symbolizes a promising therapeutic approach to avert many chronic syndromes.

Conclusion:

Importantly, the findings call for the need for a larger, rigorously designed human clinical trials to allow continued investigation into the potential specific effects of pomegranate fruit, and to obtain the best dose and duration of supplementation with pomegranate juice.

White tea modulates antioxidant defense of endurance-trained rats

The interest in nutritional strategies that may counteract the deleterious oxidative effects induced by strenuous exercises is remarkable. Herein, the impact of white tea (Camellia sinensis) (WT), a polyphenol-rich beverage, on antioxidant status in endurance-trained rats after one session of exhaustive exercise were evaluated. Male Wistar rats were divided into groups, which received: control groups - water, and testing groups - WT1 (0.25%; w/v) or WT2 (0.5%; w/v). Drinks were consumed, ad libitum, for 5 or 10 weeks, concomitantly with the running training. Exhaustive running tests were applied before and after the experimental periods. WT intake increased the serum antioxidant capacity of rats in a dose-dependent manner (P < 0.001), which was unaccompanied by the activity of endogenous antioxidant enzymes SOD, GPx, and GR, and GSH content. Inflammatory markers in serum [IL-1β (P = 0.004) and IL-6 (P = 0.001)] could be downregulated by tea intake. In liver tissue, lower levels of lipid oxidation (P < 0.05) and improved antioxidant defenses (SOD, GPx, GR, and GSH, P < 0.05) were related to the consumption of 10.13039/100010269WT in both doses, supporting protective effects in this responsible metabolic organ. In conclusion, long-term consumption of WT could be a promising adjuvant to exercise-stress management, emphasizing its ability to regulate antioxidant responses and prevent oxidative tissue damage.

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White tea intake improved antioxidant status of blood and liver of runner rats.

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White tea intake promoted protective effect against liver lipid peroxidation after an exhaustive exercise.

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Long term white tea intake did not enhance physical performance.

Tart cherry and pomegranate supplementations enhance recovery from exercise-induced muscle damage: a systematic review

Phenolic compounds have antioxidant and anti-inflammatory properties and may prevent inflammation and oxidative stress as well as help the athletes to recover from exercise-induced muscle damage (EIMD). Tart cherry (TC) and pomegranate (PG) are two fruits with high content of polyphenols. Their antioxidant and anti-inflammatory properties have recently attracted substantial interest for their potential to reduce strength loss and promote recovery from EIMD. The aims of this review are (1) to summarise the effects of tart cherry and pomegranate supplementation on oxidative stress, inflammation and recovery, and (2) to outline the differences found in supplementation with tart cherries or pomegranates. SPORTDiscus, PubMed, Web of Science and Scopus were searched according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis and 25 studies were included. The existing evidence suggests that both types of supplementation are good strategies to accelerate recovery of functional performance variables, perceptual variables and inflammation but PG supplementation shows better recovery of oxidative stress. However, positive effects are more likely: 1) when supplementation starts some days before muscle damage is induced and finishes some days after, for a total period of at least 8/10 days, 2) with pronounced muscle damage of the muscles involved, and 3) when total phenolic content is at least 1000 mg/day. This review may help to optimise TC or PG supplementation practice to improve post-exercise recovery.

Application of Pomegranate by-Products in Muscle Foods: Oxidative Indices, Colour Stability, Shelf Life and Health Benefits

In recent years, considerable importance is given to the use of agrifood wastes as they contain several groups of substances that are useful for development of functional foods. As muscle foods are prone to lipid and protein oxidation and perishable in nature, the industry is in constant search of synthetic free additives that help in retarding the oxidation process, leading to the development of healthier and shelf stable products. The by-products or residues of pomegranate fruit (seeds, pomace, and peel) are reported to contain bioactive compounds, including phenolic and polyphenolic compounds, dietary fibre, complex polysaccharides, minerals, vitamins, etc. Such compounds extracted from the by-products of pomegranate can be used as functional ingredients or food additives to harness the antioxidant, antimicrobial potential, or as substitutes for fat, and protein in various muscle food products. Besides, these natural additives are reported to improve the quality, safety, and extend the shelf life of different types of food products, including meat and fish. Although studies on application of pomegranate by-products on various foods are available, their effect on the physicochemical, oxidative changes, microbial, colour stabilizing, sensory acceptability, and shelf life of muscle foods are not comprehensively discussed previously. In this review, we vividly discuss these issues, and highlight the benefits of pomegranate by-products and their phenolic composition on human health.

Pomegranate variety and pomegranate plant part, relevance from bioactive point of view: a review

Pomegranate (Punica granatum L.) belongs to the Punicaceae plant family. It is an important fruit due to its nutritional and medicinal properties. Pomegranates are widely distributed around the world and, therefore, have a broad genetic diversity, resulting in differences in their phytochemical composition. The scientific community has focused on the positive health effects of pomegranate as a whole, but the different varieties have rarely been compared according to their bioactive compounds and bioactivity. This review aims to provide a holistic overview of the current knowledge on the bioactivity of pomegranate trees, with an emphasis on differentiating both the varieties and the different plant parts. This review intends to provide a general and organized overview of the accumulated knowledge on pomegranates, the identification of the most bioactive varieties, their potential consumption pathways and seeks to provide knowledge on the present gaps to guide future research.

Ellagic Acid as a Tool to Limit the Diabetes Burden: Updated Evidence

Oxidative stress contributes not only to the pathogenesis of type 2 diabetes (T2D) but also to diabetic vascular complications. It follows that antioxidants might contribute to limiting the diabetes burden. In this review we focus on ellagic acid (EA), a compound that can be obtained upon intestinal hydrolysis of dietary ellagitannins, a family of polyphenols naturally found in several fruits and seeds. There is increasing research on cardiometabolic effects of ellagitannins, EA, and urolithins (EA metabolites). We updated research conducted on these compounds and (I) glucose metabolism; (II) inflammation, oxidation, and glycation; and (III) diabetic complications. We included studies testing EA in isolation, extracts or preparations enriched in EA, or EA-rich foods (mostly pomegranate juice). Animal research on the topic, entirely conducted in murine models, mostly reported glucose-lowering, antioxidant, anti-inflammatory, and anti-glycation effects, along with prevention of micro- and macrovascular diabetic complications. Clinical research is incipient and mostly involved non-randomized and low-powered studies, which confirmed the antioxidant and anti-inflammatory properties of EA-rich foods, but without conclusive results on glucose control. Overall, EA-related compounds might be potential agents to limit the diabetes burden, but well-designed human randomized controlled trials are needed to fill the existing gap between experimental and clinical research.

Effects of grape juice consumption on oxidative stress and inflammation in male volleyball players: A randomized, double-blind, placebo-controlled clinical trial

INTRODUCTION

Some foods are also demonstrated benefits, such as anti-inflammatory, antioxidant, and ergogenic activity, similar to that of sports supplements. Grape juice has been considered an important source of polyphenols and these compounds could promote positive effects to the sports players. In this sense, the objective was to evaluate the effects of purple grape juice consumption on indicators of oxidative stress, inflammation, muscle damage, global histone H4 acetylation levels, and muscle strength and muscle power in volleyball athletes.

METHODS

This is a randomized double-blind clinical trial in which 12 male volleyball players (16 ± 0.6 years old) participated in three different moments with match simulation: control (without beverage) (WB), grape juice (GJ) and placebo (PLA) (400 mL/day of grape juice or placebo (maltodextrin) for 14 days in a cross-over model). Before and immediately after each match, blood collection for analysis of indicators of systemic redox status, systemic concentrations of Interferon-γ (IFN- γ) and Interleukin-4 (IL-4), muscle damage, by Creatine Kinase (CK-NAC) and levels of global histone H4 acetylation were performed, as well as handgrip strength (HG) and lower limb power tests.

RESULTS

Consumption of grape juice significantly reduced lipid peroxidation (p = 0.04) and Deoxyribonucleic Acid (DNA) damage (p = 0.01) after the match. IFN-γ levels, IL-4, CK-NAC, and histone H4 acetylation post-match did not alter with the grape juice consumption. Lower limb power improved after acute exercise in WB and GJ conditions (p < 0.001).

CONCLUSION

In this pilot trial, the intake of grape juice for two weeks seems to reduce the protein oxidation and DNA damage by intermittent physical exercise, without epigenetics influence.

A Review of Registered Clinical Trials on Dietary (Poly)Phenols: Past Efforts and Possible Future Directions

In recent years, the increasing number of studies on polyphenol demonstrates the efforts in elucidating the potential role of these bioactives on human health. This study reviews the main topics and characteristics of clinical trials on polyphenols registered over the last 20 years, in order to track past and current efforts as well as to highlight the main research gaps in this field. The review was conducted by collecting trials registered in ClinicalTrials.gov and International Standard Randomised Controlled Trial Number (ISRCTN) registry. Overall, 750 clinical trials were selected and included in the final evaluation. Most of the trials were performed on extracts or pure compounds followed by studies conducted on polyphenol-rich foods, in particular berries. A total of 520 clinical trials focused on health effects, 55 on bioavailability, and 175 on both. Regarding outcomes, 139 registered intervention studies had the lipid profile and blood pressure as primary outcomes. The overview provided by this analysis also emphasizes the emerging interest in new outcomes related to polyphenols intervention such as microbiota composition and the evaluation of inter-individual variability in response to the intake of polyphenols. Our review underlines the need of further trials covering unexplored or debated research aspects and provides insights for the design and development of future intervention studies and related research areas.

Potential health benefits of (poly)phenols derived from fruit and 100% fruit juice

(Poly)phenol-rich diets have been associated with reduced risk of various diseases. Coffee and tea are typically identified as dietary sources of chlorogenic acid and flavan-3-ols; however, 100% fruit juice greatly contributes to anthocyanin, flavonol, flavan-3-ols, and flavanone intake, making them complementary sources of dietary (poly)phenols. Thus, the aim of this narrative review was to provide an overview of fruit (poly)phenols and their potential health benefits. Fruit (poly)phenols have been associated with several health benefits (eg, reduced risk of cardiovascular disease and neurocognitive benefits). Although perspectives on 100% fruit juice consumption are controversial due to the perception of sugar content, growing evidence supports the role of fruit in whole and 100% juice forms to provide consumer benefits in alignment with dietary guidance. However, differences in (poly)phenol profiles and bioavailability likely exist between whole fruit and 100% fruit juice due to processing and the presence/absence of fiber. Ongoing studies are better defining similarities and differences between whole fruit and 100% fruit juice to elucidate protective mechanisms and align with processing and consumer products.

Oral treatment with the Chinese herbal supplements B307 enhances muscle endurance of ICR mice after exhaustive swimming via suppressing fatigue, oxidative stress, and inflammation

Exhaustive exercise may damage muscles due to oxidative stress and inflammation and cause muscle fatigue and soreness. The study investigated the effects of Chinese herbal supplements (CHS) B307 on muscle endurance after exhaustive swimming (ES). Thirty-two male ICR mice were randomly divided into 4 groups: Sham + ES, pretreatment of CHS B307 + ES (Pre + ES), post-treatment of CHS B307 + ES (Post + ES), and dual treatment of CHS B307 + ES (Dual + ES). All mice were subjected to ES in the form of a forced swimming test. Then, we compared ES time (EST) as the index of muscular endurance. Also, we examined the fatigue, oxidative stress, inflammation, and damage in the muscle tissue among these groups by using immunohistochemistry (IHC), chemiluminescence, and biochemical analysis. Our results revealed that those mice of Pre + ES and Dual + ES groups had remarkably better EST than those mice of Sham + ES and Post + ES groups. Those mice with oral treatment of CHS B307(Pre + ES, Post + ES, and Dual + ES groups) showed significantly reduced leukocyte counts in the urine, and reduced levels of reactive oxygen species (ROS), neutrophils, and lactic acid in the blood than those mice of Sham + ES. In addition, those mice with oral treatment of CHS B307 (Pre + ES, Post + ES, and Dual + ES groups) showed significant alleviation of oxidative stress, inflammation, and damage in the muscle tissue than those mice of Sham + ES. Thus, we suggested that CHS B307 can be a functional sports supplement because it can enhance muscle endurance after exhaustive swimming via suppressing fatigue, oxidative stress, and inflammation.

Modulation of Endothelial Glycocalyx and Microcirculation in Healthy Young Men during High-Intensity Sprint Interval Cycling-Exercise by Supplementation with Pomegranate Extract. A Randomized Controlled Trial

The natural components of the pomegranate fruit may provide additional benefits for endothelial function and microcirculation. It was hypothesized that supplementation with pomegranate extract might improve glycocalyx properties and microcirculation during acute high-intensity sprint interval cycling exercise. Eighteen healthy and recreationally active male volunteers 22-28 years of age were recruited randomly to the experimental and control groups. The experimental group was supplemented with pomegranate extract 20 mL (720 mg phenolic compounds) for two weeks. At the beginning and end of the study, the participants completed a high-intensity sprint interval cycling-exercise protocol. The microcirculation flow and density parameters, glycocalyx markers, systemic hemodynamics, lactate, and glucose concentration were evaluated before and after the initial and repeated (after 2 weeks supplementation) exercise bouts. There were no significant differences in the microcirculation or glycocalyx over the course of the study (p < 0.05). The lactate concentration was significantly higher in both groups after the initial and repeated exercise bouts, and were significantly higher in the experimental group compared to the control group after the repeated bout: 13.2 (11.9-14.8) vs. 10.3 (9.3-12.7) mmol/L, p = 0.017. Two weeks of supplementation with pomegranate extract does not influence changes in the microcirculation and glycocalyx during acute high-intensity sprint interval cycling-exercise. Although an unexplained rise in blood lactate concentration was observed.

The effect of synbiotics pomegranate juice on cardiovascular risk factors in PCOS patients: a randomized, triple-blinded, controlled trial

PURPOSE

Polycystic ovarian syndrome (PCOS) is one of the most common metabolic and endocrine disorders. Functional foods like pomegranate and probiotics are those that are considered to have beneficial effects on metabolic diseases beyond their basic nutritional value. So, we aimed to evaluate the effect of synbiotic pomegranate juice (SPJ) on cardiovascular risk factors on PCOS patients.

METHODS

This was a randomized, triple-blinded, 8-week trial. Participants were randomly assigned to receive 300 mL/day of pomegranate juice (PJ), synbiotic beverage (SB), synbiotic pomegranate juice (SPJ), or placebo beverage (PB). Biochemical indices (lipid profile, Total Antioxidant Capacity (TAC), Malondialdehyde (MDA), high sensitive C-Reactive Protein (hs-CRP)) and blood pressure were assessed before and after the intervention.

RESULTS

Participants in the PJ, SB, and SPJ groups experienced improvement in their lipid profile, oxidative stress, inflammation, and blood pressure during the time. Compared to placebo, Total Cholesterol (TC) was lower in the SB group (P < 0.01), LDL-c was lower in the SPJ and SB groups (P < 0.01), and HDL-c was higher in the SPJ and PJ groups (P < 0.01). With regards to oxidative stress and inflammation, when compared with placebo, MDA was lower in the SPJ, SB, and PJ groups (P < 0.001), TAC was increased in the SPJ and PJ groups (P[Formula: see text] 0.001), and hs-CRP was decreased in the PJ group (P = 0.02). Blood pressure (BP) was lower in the SPJ and PJ groups compared to placebo (P < 0.001; P < 0.01, respectively).

CONCLUSIONS

Consuming daily SPJ for 8 weeks improved metabolic, oxidative, inflammatory, and BP outcomes in females with PCOS. This trial was registered in the Iranian Registry of Clinical Trials (IRCT20170207032439N2).

Fruit-Derived Polyphenol Supplementation for Athlete Recovery and Performance

Polyphenols are characterised structurally by two or more hydroxyl groups attached to one or more benzene rings, and provide the taste and colour characteristics of fruits and vegetables. They are radical scavengers and metal chelators, but due to their low concentration in biological fluids in vivo their antioxidant properties seem to be related to enhanced endogenous antioxidant capacity induced via signalling through the Nrf2 pathway. Polyphenols also seem to possess anti-inflammatory properties and have been shown to enhance vascular function via nitric oxide-mediated mechanisms. As a consequence, there is a rationale for supplementation with fruit-derived polyphenols both to enhance exercise performance, since excess reactive oxygen species generation has been implicated in fatigue development, and to enhance recovery from muscle damage induced by intensive exercise due to the involvement of inflammation and oxidative damage within muscle. Current evidence would suggest that acute supplementation with ~ 300 mg polyphenols 1–2 h prior to exercise may enhance exercise capacity and/or performance during endurance and repeated sprint exercise via antioxidant and vascular mechanisms. However, only a small number of studies have been performed to date, some with methodological limitations, and more research is needed to confirm these findings. A larger body of evidence suggests that supplementation with > 1000 mg polyphenols per day for 3 or more days prior to and following exercise will enhance recovery following muscle damage via antioxidant and anti-inflammatory mechanisms. The many remaining unanswered questions within the field of polyphenol research and exercise performance and recovery are highlighted within this review article.

Effects of natural polyphenol-rich pomegranate juice on the acute and delayed response of Homocysteine and steroidal hormones following weightlifting exercises: a double-blind, placebo-controlled trial

BACKGROUND

Maximal strength-speed exercise is a powerful stimulus to acutely increase concentrations of circulating steroid hormones and homocysteine [Hcy]. There is some evidence that antioxidant beverages rich in polyphenols can attenuate [Hcy] levels and modulate endocrine responses in favor of an anabolic environment. Polyphenols-rich pomegranate (POM) have been reported to possess one of the highest antioxidant capacities compared to other purported nutraceuticals and other food stuffs. Studies focused on proving the beneficial effect of POM consumption during maximal strength exercises have only measured physical performance, muscle damage, oxidative stress and inflammatory responses, while POM effects on [Hcy] and hormonal adaptations are lacking. The aim of the present study was to investigate the effect of consuming natural polyphenol-rich pomegranate juice (POMj) on the acute and delayed [Hcy] and steroidal hormonal responses to a weightlifting exercises session.

METHODS

Nine elite weightlifters (21.0 ± 1 years) performed two Olympic-weightlifting sessions after ingesting either the placebo (PLA) or POMj supplements. Venous blood samples were collected at rest and 3 min and 48 h after each session.

RESULTS

Compared to baseline values, circulating cortisol [C] decreased (p < 0.01) and testosterone/cortisol [T/C] ratio increased immediately following the training session in both PLA and POMj conditions (p = 0.003 for PLA and p = 0.02 for POM). During the 48 h recovery period, all tested parameters were shown to recover to baseline values in both conditions with significant increases in [C] and decreases in [T/C] (p < 0.01 for PLA and p < 0.05 for POMj) from 3 min to 48 h post-exercises. Compared to PLA, a lower level of plasma testosterone [T] was registered 3 min post exercise using POMj supplementation (p = 0.012) and a significant decrease (p = 0.04, %change = - 14%) in plasma [Hcy] was registered during the 48 h recovery period only using POMj. A moderate correlation was observed between [Hcy] and [T] responses (p = 0.002, r = - 0.50).

CONCLUSION

In conclusion, supplementation with POMj has the potential to attenuate the acute plasma [T] response, but did not effect 48 h recovery kinetics of [Hcy] following weightlifting exercise. Further studies investigating androgen levels in both plasma and muscular tissue are needed to resolve the functional consequences of the observed acute POMj effect on plasma [T].

TRIAL REGISTRATION

Clinical Trials.gov, ID: NCT02697903. Registered 03 March 2016.

Pomegranate juice improves cardiometabolic risk factors, biomarkers of oxidative stress and inflammation in hemodialysis patients: a randomized crossover trial

BACKGROUND

Pomegranate has antioxidant, cardioprotective and anti-inflammatory properties. We designed a crossover study aimed at determining if consumption of pomegranate juice (PJ) improves lipid profile and oxidative and inflammatory biomarkers of hemodialysis patients. Forty-one hemodialysis patients were randomly assigned to one of two groups: PJ-treated group receiving 100 mL of natural PJ immediately after their dialysis session three times a week and the control group receiving the usual care. After 8 weeks, a 4-week washout period was established and then the role of the groups was exchanged. Lipid profile, blood pressure and oxidative and inflammatory biomarkers were measured before and after each sequence.

RESULTS

Based on the results of intention-to-treat analysis, triglycerides were decreased in PJ condition and increased in the controls. Conversely, high-density lipoprotein cholesterol was increased in PJ and decreased in the control group. Total and low-density lipoprotein cholesterol did not significantly change in either condition. Systolic and diastolic blood pressure significantly decreased in PJ condition. Total antioxidant capacity increased in PJ condition (P < 0.001) and decreased in the controls (P < 0.001). Conversely, malondialdehyde and interleukin-6 decreased in PJ (P < 0.001) and increased in the control group (P ≤ 0.001). The changes of these biomarkers were significantly different between the two conditions.

CONCLUSIONS

Eight-week PJ consumption showed beneficial effects on blood pressure, serum triglycerides, high-density lipoprotein cholesterol, oxidative stress and inflammation in hemodialysis patients. © 2019 Society of Chemical Industry.

Food Applications and Potential Health Benefits of Pomegranate and its Derivatives

Pomegranate (Punica granatum L.) is an ancient fruit that is particularly cultivated in west Asia, though it is also cultivated in the Mediterranean region and other parts of the world. Since ancient years, its consumption has been associated with numerous health benefits. In recent years, several in vitro and in vivo studies have revealed its beneficial physiological activities, especially its antioxidative, antimicrobial and anti-inflammatory properties. Furthermore, human-based studies have shown promising results and have indicated pomegranate potential as a protective agent of several diseases. Following that trend and the food industry's demand for antioxidants and antimicrobials from natural sources, the application of pomegranate and its extracts (mainly as antioxidants and antimicrobials), has been studied extensively in different types of food products with satisfactory results. This review aims to present all the recent studies and trends in the applications of pomegranate in the food industry and how these trends have affected product's physicochemical characteristics and shelf-life. In addition, recent in vitro and in vivo studies are presented in order to reveal pomegranate's potential in the treatment of several diseases.

Effect of pomegranate fruit supplementation on performance and various markers in athletes and active subjects: A systematic review

The aim of the study was to review recent findings on the use of POM supplements in athletes of various disciplines and physically active participants. Eleven articles published between 2010 and 2018 were included, where the total number of investigated subjects was 176. Male participants constituted the majority of the group (n = 155), as compared to females (n = 21). 45% of research described was conducted on athletes, whereas the remaining studies were based on highly active participants. Randomised, crossover, double-blind study designs constituted the majority of the experimental designs used. POM supplementation varied in terms of form (pills/juice), dosage (50 ml-500 ml) and time of intervention (7 days-2 months) between studies. Among the reviewed articles, POM supplementation had an effect on the improvement of the following: whole body strength; feeling of vitality; acute and delayed muscle fatigue and soreness; increase in vessel diameter; blood flow and serum level of TAC; reduction in the rate of increase for HR, SBP, CK and LDH; support in the recovery of post-training CK, LDH, CRP and ASAT to their baseline levels; reduction of MMP2, MMP9, hsCRP and MDA; and increased activity of antioxidant enzymes (glutathione peroxidase and superoxide dismutase). In the majority of reviewed articles POM supplementation had a positive effect on a variety of parameters studied and the authors recommended it as a supplement for athletes and physically active bodies.

Impact of anthocyanin-rich whole fruit consumption on exercise-induced oxidative stress and inflammation: a systematic review and meta-analysis

CONTEXT

Supplementing with fruits high in anthocyanins to reduce exercise-induced oxidative stress and inflammation has produced mixed results.

OBJECTIVE

This systematic review and meta-analysis aims to discuss the impact of whole fruits high in anthocyanins, including processing methods and the type and amount of fruit, on inflammation and oxidative stress.

DATA SOURCES

PICOS reporting guidelines and a customized coding scheme were used to search 5 databases (SPORTDiscus, Science Direct, Web of Science [BIOSIS], Medline [Pubmed], and the Cochrane Collaboration) with additional cross-referencing selection.

DATA EXTRACTION

A random-effects meta-analysis was used to measure effects of the fruit supplements with 3 statistics; the QTotal value based on a χ2 distribution, τ2 value, and I2 value were used to determine homogeneity of variances on 22 studies (out of 807). Outliers were identified using a relative residual value.

RESULTS

A small significant negative summary effect across the sum of all inflammatory marker outcomes (P < 0.001) and a moderate negative effect for the sum of all oxidative stress marker outcomes (P = 0.036) were found. Moderator analyses did not reveal significant (P > 0.05) differences between subgrouping variables.

CONCLUSIONS

Results indicate that consumption of whole fruit high in anthocyanins can be beneficial for reducing inflammation and oxidative stress.

Effects of antioxidant-rich foods on altitude-induced oxidative stress and inflammation in elite endurance athletes: A randomized controlled trial

Background

Various altitude training regimes, systematically used to improve oxygen carrying capacity and sports performance, have been associated with increased oxidative stress and inflammation. We investigated whether increased intake of common antioxidant-rich foods attenuates these processes.

Methods

In a randomized controlled trial, 31 elite endurance athletes (23 ± 5 years), ingested antioxidant-rich foods (n = 16), (> doubling their usual intake), or eucaloric control foods (n = 15) during a 3-week altitude training camp (2320 m). Fasting blood and urine samples were collected 7 days pre-altitude, after 5 and 18 days at altitude, and 7 days post-altitude. Change over time was compared between the groups using mixed models for antioxidant capacity [uric acid-free (ferric reducing ability of plasma (FRAP)], oxidative stress (8-epi-PGF_2α) and inflammatory biomarkers (IFNγ, IL1α, IL1RA, IL1β, IL2, IL5, IL6, IL7, IL10, IL12p70, IL13, IL17, TNFα, MCP-1 and micro-CRP). The cytokine response to a stress-test (VO_2max ramp test or 100 m swimming) was assessed at pre- and post-altitude.

Results

FRAP increased more in the antioxidant compared to the control group (p = 0.034). IL13 decreased in the antioxidant group, while increasing in the controls (p = 0.006). A similar trend was seen for IL6 (p = 0.062). A larger decrease in micro-CRP was detected in the antioxidant group compared to controls (β: -0.62, p = 0.02). We found no group differences for the remaining cytokines. 8-epi-PGF_2α increased significantly in the whole population (p = 0.033), regardless group allocation. The stress response was significantly larger post-altitude compared with pre-altitude for IL1β, IL6, IL7, IL13, IL12p70 and TNFα, but we found no group differences.

Conclusions

Increased intake of antioxidant-rich foods elevated the antioxidant capacity and attenuated some of the altitude-induced systemic inflammatory biomarkers in elite athletes. The antioxidant intervention had no impact on the altitude-induced oxidative stress or changes in acute cytokine responses to exercise stress-tests.

High-intensity-exercise-induced intestinal damage is protected by fermented milk supplemented with whey protein, probiotic and pomegranate (Punica granatum L.)

Here we evaluated the effect of fermented milk supplemented with whey protein (approximately 80 % protein), probiotic (Bifidobacterium animalis subsp. lactis BB12) and pomegranate juice (Punica granatum L.) on the physical performance, intestinal motility and villi structure, inflammatory markers and intestinal microbiota of rats under high-intensity acute exercise. In all, twenty-four Wistar rats were separated into groups: control (Ctrl), supplemented (Supp), exercised (Exe) and exercised and supplemented (Exe+Supp). Rats in the Supp groups received fermented milk during 6 weeks by oral administration. At the end of the supplementation period, the Exe groups were submitted to high-intensity acute exercise on a treadmill. We found that intense acute exercise caused changes in the intestinal villi interspace, changes in the proportion of Lactobacillus species and an increase in Clostridium species, as well as a decrease in intestinal motility. Supplementation increased intestinal motility, and maintained the intestinal villi interspace and the natural microbiota proportions of the exercised rats. Physical performance was not improved by fermented milk supplementation. We conclude that the fermented milk containing whey protein, B. animalis (BB12) and pomegranate juice can re-establish intestinal microbiota and protect the animals from the undesirable effects of intense acute exercise.

Does pomegranate consumption affect weight and body composition? A systematic review and meta-analysis of randomized controlled clinical trials

Pomegranate is rich in tannins, polyphenols, flavonoids, and several other types of antioxidant compounds whose role in weight loss has been shown in previous studies. However, the results have been mixed regarding the effects of pomegranate consumption on weight loss. Electronic databases such as PubMed, Scopus, ISI Web of Science, and Google Scholar were systematically searched up to May 2018 for controlled clinical trials assessing the effect of pomegranate consumption on weight loss. A random effects model was used to calculate the weighted mean difference (WMD) and 95% confidence interval (CI) as the difference between the mean for the intervention and control groups. Thirteen randomized controlled trials (including 513 participants) were included in the present meta-analysis. Compared with the control groups, there was no significant reduction in bodyweight, body mass index, waist circumference, and body fat percentage after pomegranate consumption (WMD = -0.23 kg, 95% CI: -0.94, 0.47, P = 0.515; WMD = -0.12 kg/m² , 95% CI: -0.29, 0.03, P = 0.132; WMD = -0.08 cm, 95% CI: -0.33, 0.17, P = 0.534; WMD = -0.05, 95% CI: -1.66, 1.55, P = 0.947, respectively). According to the results of the present systematic review and meta-analysis, there was no significant effect of pomegranate consumption on weight and body composition indices.

Effects of pomegranate supplementation on exercise performance and post-exercise recovery in healthy adults: a systematic review

The functional significance of pomegranate (POM) supplementation on physiological responses during and following exercise is currently unclear. This systematic review aimed (i) to evaluate the existing literature assessing the effects of POM supplementation on exercise performance and recovery; exercise-induced muscle damage, oxidative stress, inflammation; and cardiovascular function in healthy adults and (ii) to outline the experimental conditions in which POM supplementation is more or less likely to benefit exercise performance and/or recovery. Multiple electronic databases were used to search for studies examining the effects of POM intake on physiological responses during and/or following exercise in healthy adult. Articles were included in the review if they investigated the effects of an acute or chronic POM supplementation on exercise performance, recovery and/or physiological responses during or following exercise. The existing evidence suggests that POM supplementation has the potential to confer antioxidant and anti-inflammatory effects during and following exercise, to improve cardiovascular responses during exercise, and to enhance endurance and strength performance and post-exercise recovery. However, the beneficial effects of POM supplementation appeared to be less likely when (i) unilateral eccentric exercise was employed, (ii) the POM administered was not rich in polyphenols (<1·69 g/l) and (iii) insufficient time was provided between POM-ingestion and the assessment of physiological responses/performance (≤1 h). The review indicates that POM has the potential to enhance exercise performance and to expedite recovery from intensive exercise. The findings and recommendations from this review may help to optimise POM-supplementation practice in athletes and coaches to potentially improve exercise-performance and post-exercise recovery.

Enrichment of Apple Slices with Bioactive Compounds from Pomegranate Cryoconcentrated Juice as an Osmodehydration Agent

Pomegranate juice is an important source of bioactive compounds, and cryoconcentrated juice is an interesting osmodehydration agent to enrich a vegetal matrix. This investigation aimed to incorporate bioactive compounds from pomegranate cryoconcentrated juice into apple slices using osmodehydration (OD) assisted by pulse vacuum (PV) and ohmic heating (OH). The apple slices (3 × 4 × 0.5 cm) were osmodehydrated using a 47 °Brix pomegranate cryoconcentrated juice at 30, 40, or 50°C for 180 min with an electric field of 6.66 V/cm (50 V) and a 5 min pulsed vacuum. Over the time, all of the treatments applied to the apple slices increased the soluble solids and bioactive compounds compared with the fresh sample. PVOD/OH at 50°C had the highest content of total anthocyanin during processing, and the best results for the total flavonoids were obtained with OD/OH at 50°C and 40°C. The osmodehydration assisted by pulse vacuum and ohmic heating using a cryoconcentrated juice is a useful combined technique to acquire enriched vegetal samples with bioactive compounds.

The impact of supplementation with pomegranate fruit (Punica granatum L.) juice on selected antioxidant parameters and markers of iron metabolism in rowers

Background

The aim of this study was to analyse the effect of pomegranate juice (POM) supplementation on the levels of selected pro-inflammatory cytokines, hepcidin and markers of iron metabolism in well-trained rowers.

Method

The double-blind placebo-controlled study included 19 members of the Polish Rowing Team. The athletes were randomised into the supplemented group (n = 10), receiving 50 ml of standardised POM daily for two months, or the placebo group (n = 9). The subjects performed a 2000 m test on the rowing ergometer at the start of the project (baseline) and end of follow-up period. Blood samples from the antecubital vein were obtained three times during each trial: prior to the exercise, one minute after the test, and following a 24 h recovery.

Results

The study documented the beneficial effect of supplementation with pomegranate fruit juice on TAC (P < 0.002). During the resting period, TAC level in the supplemented group was significantly higher than in the placebo group (x ± SD, 2.49 ± 0.39 vs. 1.88 ± 0.45, P < 0.05). The ergometric test conducted at baseline demonstrated a significant post-exercise increase in the concentrations of soluble transferrin receptors (P < 0.04), iron (P < 0.002) and IL-6 (P < 0.02), and to a significant post-exercise decrease in TAC. A significant increase in IL-6 concentration was also observed 24 h post-exercise. The exercise test conducted at the end of the follow-up period resulted in a significant decrease in TBIC and a significant increase in UIBC (P < 0.001), observed in both groups, both immediately post-exercise and after the resting period.

Conclusion

Supplementation with POM contributed to a significant strengthening of plasma antioxidant potential in the group of well-trained rowers, but had no effect on iron metabolism markers.

Evaluation of microfiltration and heat treatment on the microbiological characteristics, phenolic composition and volatile compound profile of pomegranate (Punica granatum L.) juice

BACKGROUND

Since processing technology and storage may influence the sensory and nutritional value as well as the shelf life of pomegranate juice (PJ), mild technologies based on microfiltration may be a promising alternative to heat treatments for fruit juice preservation. In this study, physicochemical and microbiological properties of raw (RPJ), microfiltered (MPJ) and cloudy pasteurized (PPJ) PJ were compared over a period of 4 weeks.

RESULTS

Data demonstrated that microfiltration was comparable to pasteurization in guaranteeing microbiological stability of the juice, avoiding spoilage of the final product. After treatment, PPJ showed the highest amounts of gallic acid (GA) and ellagic acid derivatives (EAs). During storage, the amount of ellagitannins, EAs and GA similarly decreased in all types of juice. Trends towards variations of monomeric anthocyanins in MPJ and variations of polymeric and copigmented anthocyanins in both MPJ and PPJ were found over storage.

CONCLUSION

The optimization of pretreatments and filtration parameters can lead to the industrial scale-up of microfiltration technology for the development of high-quality non-heat-treated PJ. © 2017 Society of Chemical Industry.

Antioxidants for preventing and reducing muscle soreness after exercise

BACKGROUND

Muscle soreness typically occurs after intense exercise, unaccustomed exercise or actions that involve eccentric contractions where the muscle lengthens while under tension. It peaks between 24 and 72 hours after the initial bout of exercise. Many people take antioxidant supplements or antioxidant-enriched foods before and after exercise in the belief that these will prevent or reduce muscle soreness after exercise.

OBJECTIVES

To assess the effects (benefits and harms) of antioxidant supplements and antioxidant-enriched foods for preventing and reducing the severity and duration of delayed onset muscle soreness following exercise.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, SPORTDiscus, trial registers, reference lists of articles and conference proceedings up to February 2017.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials investigating the effects of all forms of antioxidant supplementation including specific antioxidant supplements (e.g. tablets, powders, concentrates) and antioxidant-enriched foods or diets on preventing or reducing delayed onset muscle soreness (DOMS). We excluded studies where antioxidant supplementation was combined with another supplement.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results, assessed risk of bias and extracted data from included trials using a pre-piloted form. Where appropriate, we pooled results of comparable trials, generally using the random-effects model. The outcomes selected for presentation in the 'Summary of findings' table were muscle soreness, collected at times up to 6 hours, 24, 48, 72 and 96 hours post-exercise, subjective recovery and adverse effects. We assessed the quality of the evidence using GRADE.

MAIN RESULTS

Fifty randomised, placebo-controlled trials were included, 12 of which used a cross-over design. Of the 1089 participants, 961 (88.2%) were male and 128 (11.8%) were female. The age range for participants was between 16 and 55 years and training status varied from sedentary to moderately trained. The trials were heterogeneous, including the timing (pre-exercise or post-exercise), frequency, dose, duration and type of antioxidant supplementation, and the type of preceding exercise. All studies used an antioxidant dosage higher than the recommended daily amount. The majority of trials (47) had design features that carried a high risk of bias due to selective reporting and poorly described allocation concealment, potentially limiting the reliability of their findings.We tested only one comparison: antioxidant supplements versus control (placebo). No studies compared high-dose versus low-dose, where the low-dose supplementation was within normal or recommended levels for the antioxidant involved.Pooled results for muscle soreness indicated a small difference in favour of antioxidant supplementation after DOMS-inducing exercise at all main follow-ups: up to 6 hours (standardised mean difference (SMD) -0.30, 95% confidence interval (CI) -0.56 to -0.04; 525 participants, 21 studies; low-quality evidence); at 24 hours (SMD -0.13, 95% CI -0.27 to 0.00; 936 participants, 41 studies; moderate-quality evidence); at 48 hours (SMD -0.24, 95% CI -0.42 to -0.07; 1047 participants, 45 studies; low-quality evidence); at 72 hours (SMD -0.19, 95% CI -0.38 to -0.00; 657 participants, 28 studies; moderate-quality evidence), and little difference at 96 hours (SMD -0.05, 95% CI -0.29 to 0.19; 436 participants, 17 studies; low-quality evidence). When we rescaled to a 0 to 10 cm scale in order to quantify the actual difference between groups, we found that the 95% CIs for all five follow-up times were all well below the minimal important difference of 1.4 cm: up to 6 hours (MD -0.52, 95% CI -0.95 to -0.08); at 24 hours (MD -0.17, 95% CI -0.42 to 0.07); at 48 hours (MD -0.41, 95% CI -0.69 to -0.12); at 72 hours (MD -0.29, 95% CI -0.59 to 0.02); and at 96 hours (MD -0.03, 95% CI -0.43 to 0.37). Thus, the effect sizes suggesting less muscle soreness with antioxidant supplementation were very unlikely to equate to meaningful or important differences in practice. Neither of our subgroup analyses to examine for differences in effect according to type of DOMS-inducing exercise (mechanical versus whole body aerobic) or according to funding source confirmed subgroup differences. Sensitivity analyses excluding cross-over trials showed that their inclusion had no important impact on results.None of the 50 included trials measured subjective recovery (return to previous activities without signs or symptoms).There is very little evidence regarding the potential adverse effects of taking antioxidant supplements as this outcome was reported in only nine trials (216 participants). From the studies that did report adverse effects, two of the nine trials found adverse effects. All six participants in the antioxidant group of one trial had diarrhoea and four of these also had mild indigestion; these are well-known side effects of the particular antioxidant used in this trial. One of 26 participants in a second trial had mild gastrointestinal distress.

AUTHORS' CONCLUSIONS

There is moderate to low-quality evidence that high dose antioxidant supplementation does not result in a clinically relevant reduction of muscle soreness after exercise at up to 6 hours or at 24, 48, 72 and 96 hours after exercise. There is no evidence available on subjective recovery and only limited evidence on the adverse effects of taking antioxidant supplements. The findings of, and messages from, this review provide an opportunity for researchers and other stakeholders to come together and consider what are the priorities, and underlying justifications, for future research in this area.

Pomegranate juice, but not an extract, confers a lower glycemic response on a high-glycemic index food: randomized, crossover, controlled trials in healthy subjects

Background: Low-glycemic index diets have demonstrated health benefits associated with a reduced risk of developing type 2 diabetes.Objectives: We tested whether pomegranate polyphenols could lower the glycemic response of a high-glycemic index food when consumed together and the mechanism by which this might occur.Design: We compared the acute effect of a pomegranate juice and a polyphenol-rich extract from pomegranate (supplement) on the bread-derived postprandial blood glucose concentration in 2 randomized, crossover, controlled studies (double-blinded for the supplements), each on 16 healthy volunteers. An additional randomized, crossover, controlled study on 16 volunteers consuming constituent fruit acids in a pH-balanced solution (same pH as pomegranate) and bread was conducted to determine any contributions to postprandial responses caused by acidic beverages.Results: As primary outcome, the incremental area under the curve for bread-derived blood glucose (-33.1% ± 18.1%, P = 0.000005) and peak blood glucose (25.4% ± 19.3%, P = 0.0004) were attenuated by pomegranate juice, compared with a control solution containing the equivalent amount of sugars. In contrast, the pomegranate supplement, or a solution containing the malic and citric acid components of the juice, was ineffective. The pomegranate polyphenol punicalagin was a very effective inhibitor of human α-amylase in vitro, comparable to the drug acarbose. Neither the pomegranate extract nor the individual component polyphenols inhibited ¹⁴C-D-glucose transport across differentiated Caco-2/TC7 cell monolayers, but they inhibited uptake of ¹⁴C-glucose into Xenopus oocytes expressing the human glucose transporter type 2. Further, some of the predicted pomegranate gut microbiota metabolites modulated ¹⁴C-D-glucose and ¹⁴C-deoxy-D-glucose uptake into hepatic HepG2 cells.Conclusions: These data indicate that pomegranate polyphenols, when present in a beverage but not in a supplement, can reduce the postprandial glycemic response of bread, whereas microbial metabolites from pomegranate polyphenols exhibit the potential to further modulate sugar metabolism much later in the postprandial period. This trial was registered at clinicaltrials.gov as NCT02486978, NCT02624609, and NCT03242876.

Lack of efficacy of pomegranate supplementation for glucose management, insulin levels and sensitivity: evidence from a systematic review and meta-analysis

Background

The potential glucose-lowering effects of pomegranate have been reported in animal and observational studies, but intervention studies in humans have generated mixed results. In this paper, we aimed to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the precise effects of pomegranate supplementation on measures of glucose control, insulin levels and insulin sensitivity in humans.

Methods

Comprehensive electronic searches were conducted in PubMed, Embase, and the Cochrane Library. Studies included were RCTs that evaluated the changes in diabetes biomarkers among adults (≥18 years) following pomegranate interventions. The predefined outcomes included fasting blood glucose (FBG), fasting blood insulin (FBI), glycated haemoglobin (HbA1c), and homeostatic model assessment of insulin resistance (HOMA-IR). Endpoints were calculated as weighted mean differences (WMDs) with 95% confidence intervals (CIs) by using a random-effects model. Publication bias, subgroup analyses, sensitivity analysis and random-effects meta-regression were also performed to explore the influence of covariates on the net changes in fasting glucose and insulin concentrations.

Results

Sixteen eligible trials with 538 subjects were included. The pooled estimates suggested that pomegranate did not significantly affect the measures of FBG (WMD, −0.6 mg/dL; 95% CI, −2.79 to 1.58; P=0.59), FBI (WMD, 0.29 μIU/mL; 95% CI, −1.16 to 1.75; P=0.70), HOMA-IR (WMD, −0.04; 95% CI, −0.53 to 0.46; P=0.88) or HbA1c (WMD, −0.11%; 95% CI, −0.39 to −0.18; P=0.46). Overall, significant heterogeneity was detected for FBI and HOMA-IR, but subgroup analysis could not identify factors significantly influencing these parameters. These results were robust in sensitivity analysis, and no significant publication bias was found in the current meta-analysis.

Conclusion

Pomegranate intake did not show a notably favourable effect on improvements in glucose and insulin metabolism. The current evidence suggests that daily pomegranate supplementation is not recommended as a potential therapeutic strategy in glycemic management. Further large-scale RCTs with longer duration are required to confirm these results.

Electronic supplementary material

The online version of this article (10.1186/s12937-017-0290-1) contains supplementary material, which is available to authorized users.

Punicalagin, a PTP1B inhibitor, induces M2c phenotype polarization via up-regulation of HO-1 in murine macrophages

Current data have shown that punicalagin (PUN), an ellagitannin isolated from pomegranate, possesses anti-inflammatory and anti-oxidant properties; however, its direct targets have not yet been reported. This is the first report that PTP1B serves as a direct target of PUN, with IC₅₀ value of 1.04μM. Results from NPOI further showed that the K_on and K_off of PUN-PTP1B complex were 3.38e2M^-1s^-1 and 4.13e-3s^-1, respectively. The active site Arg24 of PTP1B was identified as a key binding site of PUN by computation simulation and point mutation. Moreover, inhibition of PTP1B by PUN promoted an M2c-like macrophage polarization and enhanced anti-inflammatory cytokines expression, including IL-10 and M-CSF. Based on gene expression profile, we elucidated that PUN treatment significantly up-regulated 275 genes and down-regulated 1059 genes. M1-like macrophage marker genes, such as Tlr4, Irf1/2, Hmgb1, and Stat1 were down-regulated, while M2 marker genes, including Tmem171, Gpr35, Csf1, Il1rn, Cebpb, Fos, Vegfα, Slc11a1, and Bhlhe40 were up-regulated in PUN-treated macrophages. Hmox-1, a gene encoding HO-1 protein, was preferentially expressed with 16-fold change. Inhibition of HO-1 obviously restored PUN-induced M2 polarization and IL-10 secretion. In addition, phosphorylation of both Akt and STAT3 contributed to PUN-induced HO-1 expression. This study provided new insights into the mechanisms of PUN-mediated anti-inflammatory and anti-oxidant activities and provided new therapeutic strategies for inflammatory diseases.

New findings of oxidative stress biomarkers in nutritional research

PURPOSE OF REVIEW

The aim of this article is to present a brief overview of recently published articles assessing oxidative stress markers in nutritional studies.

RECENT FINDINGS

Intervention and observational studies were carried out in both, healthy subjects and patients and describe the association of foodstuffs as well as isolated nutrients with biomarkers of oxidative stress. The results from human intervention studies on healthy participants and patients are controversial. Long-term interventions (>8 weeks) seem to be more effective than short-term or single-dose interventions. Results are difficult to compare because not only the methods used, also the assessed biomarkers and outcomes were very diverse. In addition, studies vary in the compounds and doses used, duration, participants and so on. Different biomarkers (damaged molecules together with antioxidants from different compartments) should be assessed to evaluate the true 'redox-status' of an individual and the impact of a nutritional intervention.

SUMMARY

Both observational and interventional studies performed in healthy participants and patients show possible beneficial effects of nutrients and foodstuffs by improving oxidative stress markers and antioxidant enzyme activities. Biomarkers should be standardized to allow better comparison of results of antioxidant intervention studies.

An Acute Dose of Specific Grape and Apple Polyphenols Improves Endurance Performance: A Randomized, Crossover, Double-Blind versus Placebo Controlled Study

Polyphenols are thought to be an interesting ergogenic aid for exercise and recovery. However, most studies regarding the effects of polyphenols investigated several days of supplementations. The present work aimed to study the effects of an acute intake of grape and apple polyphenols on the capacity to maintain intense exercise, here named endurance performance. Forty-eight physically active men (31 ± 6 years) were included in this study. During the two testing sessions, volunteers completed an endurance test at a high percentage of their maximal aerobic power and time to exhaustion was measured. Respiratory and pain parameters were also monitored. The preceding evening and 1 h before testing, volunteers had to absorb either 500 mg of polyphenols or placebo according to randomization. In comparison with the placebo, the mean duration of the maximal endurance test was significantly increased with polyphenols (+9.7% ± 6.0%, p < 0.05). The maximal perceived exertion was reached later with polyphenols (+12.8% ± 6.8%, p < 0.05). Practically, the present study showed the beneficial effects of grape and apple polyphenols for athletes looking for endurance performance improvements. The specifically designed profile of polyphenols appeared to enhance the capacity to maintain intensive efforts and delay perceived exertion.

Effects of Pomegranate Juice Supplementation on Oxidative Stress Biomarkers Following Weightlifting Exercise

The aim of this study was to test the hypothesis that pomegranate juice supplementation would blunt acute and delayed oxidative stress responses after a weightlifting training session. Nine elite weightlifters (21.0 ± 1 years) performed two Olympic-Weightlifting sessions after ingesting either the placebo or pomegranate juice supplements. Venous blood samples were collected at rest and 3 min and 48 h after each session. Compared to the placebo condition, pomegranate juice supplementation attenuated the increase in malondialdehyde (−12.5%; p < 0.01) and enhanced the enzymatic (+8.6% for catalase and +6.8% for glutathione peroxidase; p < 0.05) and non-enzymatic (+12.6% for uric acid and +5.7% for total bilirubin; p < 0.01) antioxidant responses shortly (3 min) after completion of the training session. Additionally, during the 48 h recovery period, pomegranate juice supplementation accelerated (p < 0.05) the recovery kinetics of the malondialdehyde (5.6%) and the enzymatic antioxidant defenses compared to the placebo condition (9 to 10%). In conclusion, supplementation with pomegranate juice has the potential to attenuate oxidative stress by enhancing antioxidant responses assessed acutely and up to 48 h following an intensive weightlifting training session. Therefore, elite weightlifters might benefit from blunted oxidative stress responses following intensive weightlifting sessions, which could have implications for recovery between training sessions.

Oxidative stress and inflammation: liver responses and adaptations to acute and regular exercise

The liver is remarkably important during exercise outcomes due to its contribution to detoxification, synthesis, and release of biomolecules, and energy supply to the exercising muscles. Recently, liver has been also shown to play an important role in redox status and inflammatory modulation during exercise. However, while several studies have described the adaptations of skeletal muscles to acute and chronic exercise, hepatic changes are still scarcely investigated. Indeed, acute intense exercise challenges the liver with increased reactive oxygen species (ROS) and inflammation onset, whereas regular training induces hepatic antioxidant and anti-inflammatory improvements. Acute and regular exercise protocols in combination with antioxidant and anti-inflammatory supplementation have been also tested to verify hepatic adaptations to exercise. Although positive results have been reported in some acute models, several studies have shown an increased exercise-related stress upon liver. A similar trend has been observed during training: while synergistic effects of training and antioxidant/anti-inflammatory supplementations have been occasionally found, others reported a blunting of relevant adaptations to exercise, following the patterns described in skeletal muscles. This review discusses current data regarding liver responses and adaptation to acute and regular exercise protocols alone or combined with antioxidant and anti-inflammatory supplementation. The understanding of the mechanisms behind these modulations is of interest for both exercise-related health and performance outcomes.