Lack of a Synergistic Effect on Cardiometabolic and Redox Markers in a Dietary Supplementation with Anthocyanins and Xanthophylls in Postmenopausal Women

Immunomodulatory Role of Plants and Their Constituents on the Management of Metabolic Disorders: An Evidence-Based Review

The relationship between the immune system and metabolic diseases is complex and increasingly recognized as critical to understanding conditions like obesity, diabetes, and cardiovascular diseases. Modulation of the immune system in patients with metabolic disorders can offer several potential benefits. While the salutary impact of plant-derived bioactive compounds on metabolic and immune functions is acknowledged, there is a paucity of comprehensive reviews on the multifaceted and synergistic mechanisms through which these effects are mediated. This review elucidates the therapeutic potential of phytochemical formulations in ameliorating metabolic disorders and delineates their mechanistic implications on relevant biomarkers and immune modulation. Our analysis reveals a predominance of plant species, including Boswellia serrata, Cinnamomum cassia, Citrus bergamia, Coffea arabica, Ficus racemosa, Momordica charantia, Morus Alba, and Trigonella foenum-graecum, that have undergone clinical evaluation and have been substantiated to confer both metabolic and immunological benefits. The phytoconstituents contained in these plants exert their effects through a range of mechanisms, such as improving glucose regulation, reducing inflammatory responses, and modulating immune system. As such, these findings hold considerable promise for clinical and therapeutic translation and necessitate further empirical validation through randomized controlled trials and mechanistic elucidations to affirm the safety and efficacy of herbal formulations.

Effect of carotenoid supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

CONTEXT

Hypertension (HTN) is regarded as a serious public health issue throughout the world. High blood pressure (BP) may be improved by carotenoid supplementation; however, randomized controlled trials (RCTs) provide conflicting evidence.

OBJECTIVE

The aim of this study was to evaluate the effects of carotenoid supplementation on BP in RCTs by systematically review and meta-analysis.

DATA SOURCES

A comprehensive literature search was performed in the Scopus, PubMed, and Web of Science databases until October 2023, with no limitation on the date or language of publication.

DATA EXTRACTION

Studies that evaluated the net effects of carotenoids in the form of supplements on BP in adults were selected. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated on the basis of a fixed or random-effects model. Sensitivity analysis, meta-regression, publication bias, and heterogeneity were assessed using standard methods. Cochrane quality assessments were used to evaluate the included studies' bias risks. Evidence certainty was calculated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework).

DATA ANALYSIS

Reports on a total of 19 RCTs involving 1151 participants were included in this review. Carotenoid supplementation significantly reduced the systolic BP (SBP) (WMD, -2.492 mmHg; 95%CI, -4.52, -0.47; P = 0.016) and diastolic BP (DBP) (WMD, -1.60 mmHg; 95%CI, -2.73, -0.47; P = 0.005). Greater effects were observed in Asian participants, those aged >50 years, nonhealthy participants, and participants with a baseline SBP ≥130 mmHg and DBP ≥80 mmHg, at dose >10 mg. Dose-response analysis showed that carotenoid supplementation decreased SBP and DBP levels at doses of, respectively, 0-25 and 0-20 mg/d. Evidence for all SBP, DBP, and heart rate values was high quality.

CONCLUSIONS

Carotenoid supplementation had a beneficial effect on BP parameters, especially in nonhealthy study participants with high BP baseline levels.

PROSPERO REGISTRATION NO

CRD42023402740.

Anthocyanin Effects on Vascular and Endothelial Health: Evidence from Clinical Trials and Role of Gut Microbiota Metabolites

Hypertension and derived cardiovascular disease (CVD) are among the leading causes of death worldwide. Increased oxidative stress and inflammatory state are involved in different alterations in endothelial functions that contribute to the onset of CVD. Polyphenols, and in particular anthocyanins, have aroused great interest for their antioxidant effects and their cardioprotective role. However, anthocyanins are rarely detected in blood serum because they are primarily metabolized by the gut microbiota. This review presents studies published to date that report the main results from clinical studies on the cardioprotective effects of anthocyanins and the role of the gut microbiota in the metabolism and bioavailability of anthocyanins and their influence on the composition of the microbiota. Even if it seems that anthocyanins have a significant effect on vascular health, more studies are required to better clarify which molecules and doses show vascular benefits without forgetting the crucial role of the microbiota.

The landscape of potential health benefits of carotenoids as natural supportive therapeutics in protecting against Coronavirus infection

The Coronavirus Disease-2019 (COVID-19) pandemic urges researching possibilities for prevention and management of the effects of the virus. Carotenoids are natural phytochemicals of anti-oxidant, anti-inflammatory and immunomodulatory properties and may exert potential in aiding in combatting the pandemic. This review presents the direct and indirect evidence of the health benefits of carotenoids and derivatives based on in vitro and in vivo studies, human clinical trials and epidemiological studies and proposes possible mechanisms of action via which carotenoids may have the capacity to protect against COVID-19 effects. The current evidence provides a rationale for considering carotenoids as natural supportive nutrients via antioxidant activities, including scavenging lipid-soluble radicals, reducing hypoxia-associated superoxide by activating antioxidant enzymes, or suppressing enzymes that produce reactive oxygen species (ROS). Carotenoids may regulate COVID-19 induced over-production of pro-inflammatory cytokines, chemokines, pro-inflammatory enzymes and adhesion molecules by nuclear factor kappa B (NF-κB), renin-angiotensin-aldosterone system (RAS) and interleukins-6- Janus kinase-signal transducer and activator of transcription (IL-6-JAK/STAT) pathways and suppress the polarization of pro-inflammatory M1 macrophage. Moreover, carotenoids may modulate the peroxisome proliferator-activated receptors γ by acting as agonists to alleviate COVID-19 symptoms. They also may potentially block the cellular receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), human angiotensin-converting enzyme 2 (ACE2). These activities may reduce the severity of COVID-19 and flu-like diseases. Thus, carotenoid supplementation may aid in combatting the pandemic, as well as seasonal flu. However, further in vitro, in vivo and in particular long-term clinical trials in COVID-19 patients are needed to evaluate this hypothesis.

Serum Lutein and Zeaxanthin Are Inversely Associated with High-Sensitivity C-Reactive Protein in Non-Smokers: The Mikkabi Study

Recent randomized controlled trials have demonstrated a protective association between carotenoids and inflammation; however, the basis of this association on lifestyle factors remains unclear. This study aimed to clarify the associations between carotenoids and inflammatory markers stratified by lifestyle factors, using baseline data from the Mikkabi Study. Serum carotenoid and high-sensitivity C-reactive protein (hs-CRP) levels were measured. Multivariable adjusted odds ratios (ORs) for a high hs-CRP level (≥2.0 mg/dL) were obtained using logistic regression analysis. The data of 882 individuals were analyzed; 11.7% had high hs-CRP levels. The highest tertile of lutein (OR: 0.44; 95% confidence interval [CI]: 0.25–0.76), zeaxanthin (OR: 0.36; 95% CI: 0.21–0.64), total carotenoid (OR: 0.57; 95% CI: 0.32–0.9997), and oxygenated carotenoid concentration (OR: 0.50; 95% CI: 0.28–0.90), with the lowest tertile as reference, was inversely associated with a high hs-CRP level. The interaction between lutein, but not other carotenoids, and current smoking was significant. The inverse association between lutein and a high hs-CRP level was significant in non-smokers (OR: 0.41; 95% CI: 0.22–0.76) but not in smokers. These results further support the anti-inflammatory effect of carotenoids; nevertheless, further studies should clarify the interaction of smoking with the association between lutein and inflammation.

A Systematic Review of the Cardiometabolic Benefits of Plant Products Containing Mixed Phenolics and Polyphenols in Postmenopausal Women: Insufficient Evidence for Recommendations to This Specific Population

Menopause is characterized by endocrine and physiological changes and is often accompanied by increased body weight and cholesterol, glucose intolerance, and/or hypertension. These alterations are associated with increased risk for cardiovascular diseases (CVDs) and Type II diabetes mellitus (T2DM) that may be moderate by dietary plant phenolic compounds. In this review, we examine the current evidence of the impact of a variety of plant products (foods, extracts, beverages) rich in a mixture of phenolics and polyphenols on: (i) glucose and insulin levels; (ii) lipid profile; (iii) blood pressure; and (iv) biomarkers of inflammation and oxidative stress in postmenopausal women. We critically evaluate both the results of a range of intervention studies conducted in this specific subpopulation and the level of evidence supporting the benefits of consuming those products after the menopause. Overall, the current available evidence does not allow for specific dietary recommendations of these plant products rich in phenolics and polyphenols in this high-risk subpopulation. Our data show rather variable and small effects of the different products examined on the cardiometabolic biomarkers and further support the need to: (1) improve the quality of the study designs and data reporting; and (2) understand the variability in the response of the different biomarkers and establish clear differences between healthy and cardiometabolic disease levels.

Targeting Inflammation by Anthocyanins as the Novel Therapeutic Potential for Chronic Diseases: An Update

Low-grade chronic inflammation (LGCI) and oxidative stress act as cooperative and synergistic partners in the pathogenesis of a wide variety of diseases. Polyphenols, including anthocyanins, are involved in regulating the inflammatory state and activating the endogenous antioxidant defenses. Anthocyanins' effects on inflammatory markers are promising and may have the potential to exert an anti-inflammatory effect in vitro and in vivo. Therefore, translating these research findings into clinical practice would effectively contribute to the prevention and treatment of chronic disease. The present narrative review summarizes the results of clinical studies from the last 5 years in the context of the anti-inflammatory and anti-oxidative role of anthocyanins in both health and disease. There is evidence to indicate that anthocyanins supplementation in the regulation of pro-inflammatory markers among the healthy and chronic disease population. Although the inconsistencies between the result of randomized control trials (RCTs) and meta-analyses were also observed. Regarding anthocyanins' effects on inflammatory markers, there is a need for long-term clinical trials allowing for the quantifiable progression of inflammation. The present review can help clinicians and other health care professionals understand the importance of anthocyanins use in patients with chronic diseases.

Carotenoids supplementation and inflammation: a systematic review and meta-analysis of randomized clinical trials

The aim of this study was to perform a systematic review and meta-analysis on randomized controlled trials investigating the effects of carotenoids on selected inflammatory parameters. PubMed, SCOPUS, and Web of science were searched from inception until April 2021. The random-effect model was used to analyze data and the overall effect size was computed as weighted mean difference (WMD) and corresponding 95% of confidence interval (CI). A total of 26 trials with 35 effect sizes were included in this meta-analysis. The results indicated significant effects of carotenoids on C-reactive protein (CRP) (WMD: ‒0.54 mg/L, 95% CI: ‒0.71, ‒0.37, P < 0.001), and interleukin-6 (IL-6) (WMD: ‒0.54 pg/mL, 95% CI: ‒1.01, ‒0.06, P = 0.025), however the effect on tumor necrosis factor-alpha (TNF-α) was not significant (WMD: ‒0.97 pg/ml, 95% CI: ‒1.98, 0.03, P = 0.0.059). For the individual carotenoids, astaxanthin, (WMD: ‒0.30 mg/L, 95% CI: ‒0.51, ‒0.09, P = 0.005), lutein/zeaxanthin (WMD: ‒0.30 mg/L, 95% CI: ‒0.45, ‒0.15, P < 0.001), and β-cryptoxanthin (WMD: ‒0.35 mg/L, 95% CI: ‒0.54, ‒0.15, P < 0.001) significantly decreased CRP level. Also, only lycopene (WMD: ‒1.08 pg/ml, 95%CI: ‒2.03, ‒0.12, P = 0.027) led to a significant decrease in IL-6. The overall results supported possible protective effects of carotenoids on inflammatory biomarkers.

A Dietary Intervention High in Green Leafy Vegetables Reduces Oxidative DNA Damage in Adults at Increased Risk of Colorectal Cancer: Biological Outcomes of the Randomized Controlled Meat and Three Greens (M3G) Feasibility Trial

Green leafy vegetables (GLV) may reduce the risk of red meat (RM)-induced colonic DNA damage and colorectal cancer (CRC). We previously reported the primary outcomes (feasibility) of a 12-week randomized controlled crossover trial in adults with habitual high RM and low GLV intake with body mass index (BMI) > 30 kg/m² (NCT03582306). Herein, our objective was to report a priori secondary outcomes. Participants were recruited and enrolled in 2018, stratified by gender, and randomized to two arms: immediate intervention group (IG, n = 26) or delayed intervention group (DG, n = 24). During the 4 week intervention period, participants were provided with frozen GLV and counseled to consume 1 cooked cup equivalent daily. Participants consumed their normal diet for the remaining 8 weeks. At each of four study visits, anthropometrics, stool, and blood were taken. Overall, plasma Vitamin K1 (0.50 ± 1.18 ng/mL, p < 0.001) increased, while circulating 8OHdG (−8.52 ± 19.05 ng/mL, p < 0.001), fecal 8OHdG (−6.78 ± 34.86 ng/mL, p < 0.001), and TNFα (−16.95 ± 60.82 pg/mL, p < 0.001) decreased during the GLV intervention compared to control periods. Alpha diversity of fecal microbiota and relative abundance of major taxa did not differ systematically across study periods. Further investigation of the effects of increased GLV intake on CRC risk is warranted.

Redox biomarkers in dietary interventions and nutritional observation studies - From new insights to old problems

Purpose

The purpose of this review is to give an overview on recently published articles investigating the associations of diet and dietary interventions with biomarkers of oxidative stress with special emphasis on different categories of redox biomarkers.

Findings

Intervention and observational studies both in healthy participants and patients that investigated associations of dietary habits, foodstuffs or isolated nutrients with biomarkers of oxidative stress were included in this review. Recently published observation studies confirm the inverse association between fruit and vegetable intake and oxidative stress markers. Studies investigating the effect of vitamin D and vitamin E, magnesium, zinc, chromium, selenium, probiotic supplementation and several phytochemicals reported consistent changes in redox biomarkers. Of 88 articles included in this review, only seven studies measured biomarkers from the three categories: oxidative damage, endogenous antioxidants, and exogenous antioxidants. Many studies rely on controversial assays for total antioxidant capacity, thus there is potential in many studies to improve biomarker repertoire to cover all three categories of biomarkers and to turn away from such assays.

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Oxidative stress can be assessed by specific biomarker categories.

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Three biomarker categories: oxidative damage, endogenous, exogenous antioxidants.

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Only seven studies performed measurements of all three biomarker categories.

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TAC, TRAP, FRAP, ORAC should not be used as stand-alone redox marker.

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Several interventions reported improvements in markers of oxidative stress.

Anthocyanin supplementation improves anti-oxidative and anti-inflammatory capacity in a dose-response manner in subjects with dyslipidemia

BACKGROUND

Anthocyanins, one of the major plant bioactive substances, possess anti-oxidative and anti-inflammatory capacity. However, their dose-response relationship has remained unclear. The present study investigated the dose-response relationship of anthocyanins with oxidative stress and inflammation in subjects with dyslipidemia.

DESIGN

and Participants: A total of 169 participants with dyslipidemia were randomly assigned to placebo (n = 43), anthocyanins 40 mg/day (n = 44), 80 mg/day (n = 40), or 320 mg/day (n = 42) groups. Urine 8-iso-prostaglandin F2α (8-iso-PGF2α), 8-hydroxy-2'-deoxyguanosine (8-OHdG) and serum malonaldehyde (MDA), total superoxide dismutase (T-SOD), UA (uric acid), interleukin (IL)-6, IL-10, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) were measured at baseline, at 6 weeks, and at 12 weeks.

RESULTS

Anthocyanin supplementation (320 mg/day) for 6 weeks significantly improved T-SOD versus baseline (P < 0.05). A slight reduction in serum IL-6, TNF-α, and urine 8-iso-PGF2α from the baseline was observed at 12 weeks in the group receiving 40 mg/day anthocyanins. Anthocyanins (80 mg/day) significantly reduced serum IL-6 (-20%), TNF-α (-11%) and urine 8-iso-PGF2α (-27%) versus baseline (P < 0.05). Moreover, 320 mg/day anthocyanin supplementation reduced serum IL-6 (-40%), TNF-α (-21%), MDA (-20%) and urine 8-iso-PGF2α (-37%) and 8-OHdG (-36%) than 80 mg/day and 40 mg/day anthocyanins, P value < 0.05. Anthocyanin supplementation has dose-response relationships with decreased inflammatory cytokines IL-6, TNF-α and oxidative stress biomarkers 8-iso-PGF2α, 8-OHdG and MDA (P for trend, <0.05). Furthermore, a strong positive correlation was observed between the changes in the urine 8-iso-PGF2α , 8-OHdG levels and serum IL-6 levels in subjects from anthocyanin groups after 12 weeks of treatment.

CONCLUSIONS

Supplementation of anthocyanins for 12 weeks positively improved the anti-oxidative and anti-inflammatory capacity in a dose-response manner in individuals with dyslipidemia.

Polyphenol-Rich Foods for Human Health and Disease

Polyphenols are a class of well-known bioactive compounds widely distributed in the plant kingdom and abundant in plant foods and derived food products [...].