Cocoa and its products are rich sources of polyphenols such as flavanols. These compounds exert antioxidant and anti-inflammatory activities, accountable for cocoa health-promoting effects. However, cocoa polyphenols are poorly absorbed in the intestine, and most of them cannot reach the systemic circulation in their natural forms. Instead, their secondary bioactive metabolites are bioavailable, enter the circulation, reach the target organs, and exhibit their activities. In fact, once reaching the intestine, cocoa polyphenols interact bidirectionally with the gut microbiota. These compounds can modulate the composition of the gut microbiota exerting prebiotic mechanisms. They enhance the growth of beneficial gut bacteria, such as Lactobacillus and Bifidobacterium, while reducing the number of pathogenic ones, such as Clostridium perfringens. On the other hand, bioactive cocoa metabolites can enhance gut health, displaying anti-inflammatory activities, positively affecting immunity, and reducing the risk of various diseases. This review aims to summarize the available knowledge of the bidirectional interaction between cocoa polyphenols and gut microbiota with their various health outcomes.

Recent evidence suggests that diet can modify the risk of future cognitive impairment and dementia. A biologically plausible rationale and initial clinical data indicate that the antioxidant activities of dietary carotenoids may assist the preservation of cognitive function. A meta-analysis of randomized controlled trials was conducted to examine the relationship between carotenoid supplementation and cognitive performance. A literature search was conducted in the MEDLINE (via PubMed), Scopus, Web of Science, and Cochrane databases from their inception to July 2020. A total of 435 studies were retrieved. Abstract screening using predefined inclusion and exclusion criteria was followed by full-text screening and data extraction of study characteristics and measured outcomes. A meta-analysis of eligible trials was performed using a random-effects model to estimate pooled effect size. We identified 9 studies with a total of 4402 nondemented subjects, whose age ranged from 45 to 78 years. Results of the pooled meta-analysis found a significant effect of carotenoid intervention on cognitive outcomes (Hedge’s g = 0.14; 95% confidence interval: 0.08, 0.20, p < 0.0001). There was no evidence of heterogeneity among the studies (τ2 = 0.00, I2 = 0.00%, H2 = 1.00) or publication bias. Although further studies are needed, our results suggest that carotenoid interventions are associated with better cognitive performance. Thus, these dietary compounds may help to reduce the risk of cognitive impairment and dementia.

Background: Emerging studies show that certain plant compounds may reduce the severity of most prevalent ocular abnormalities. The aim of this systematic review and meta-analysis was to assess the effect of dietary flavonoids on major eye disorders.Methods: Eligible studies were identified by searching PubMed, Web of Science, Scopus, and Cochrane Library databases for all articles published up to April 2021. The literature search yielded 1,134 articles, and a total of 16 studies were included in the systematic review. A meta-analysis of 11 intervention trials involving a total of 724 participants was performed.Results: Using a random-effects model, the pooled results revealed an overall significant effect of flavonoids on common ophthalmic disorders (standard mean difference = −0.39; 95% CI: −0.56, −0.21, p &lt; 0.01). Of the subclasses of flavonoids, flavan-3-ols (standard mean difference = −0.62; 95% CI: −1.03, −0.22, p &lt; 0.01), and anthocyanins (standard mean difference = −0.42; 95% CI: −0.63, −0.21, p &lt; 0.01) were the only effective intervention for improving the outcomes of ocular conditions. For several of the other flavonoid subclasses, evidence on efficacy was insufficient.Conclusion: Our findings indicate that flavonoids may improve the clinical manifestations associated with ocular disorders. However, further well-constructed clinical trials are required to confirm these results and examine the effect of flavonoids on eye disorders other than those identified in this review.Systematic Review Registration: PROSPERO, identifier CRD42021247332.

Dry eye disease (DED) is a multifactorial condition caused by tear deficiency and accompanied by ocular surface damage. Recent data support a key role of oxidative and inflammatory processes in the pathogenesis of DED. Hyaluronic acid (HA) is widely used in artificial tears to treat DED by improving ocular hydration and reducing surface friction. Crocin (Cr), the main constituent of saffron, is a renowned compound that exhibits potent antioxidant and anti-inflammatory effects. The present study was undertaken to assess the viscosity and muco-adhesiveness of a photoactivated formulation with crosslinked HA (cHA), Cr, and liposomes (cHA-Cr-L). Our aim was also to evaluate whether cHA-Cr-L may exert cytoprotective effects against oxidative and inflammatory processes in human corneal epithelial cells (HCECs). Viscosity was measured using a rotational rheometer, and then the muco-adhesiveness was evaluated. Under hyperosmolarity (450 mOsm), the HCECs were treated with cHA-Cr-L. Interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) were quantified by quantitative real-time polymerase chain reaction (RT-qPCR). The levels of reactive oxygen species (ROS) were measured using the DCF assay. The combined action of cHA-Cr-L produced a higher viscosity and muco-adhesiveness compared to the control. The anti-inflammatory effect of cHA-Cr-L was achieved through a significant reduction of IL-1β and TNFα (p < 0.001). The results also showed that cHA-Cr-L reduces ROS production under conditions of hyperosmolarity (p < 0.001). We conclude that cHA-Cr-L has potential as a therapeutic agent in DED, which should be further investigated.

Recent evidence suggests that diet modifies key biological factors associated with the development of depression. It has been suggested that this could be due to the high flavonoid content commonly found in many plant foods, beverages and dietary supplements. Our aim was to conduct a systematic review to evaluate the effects of dietary flavonoids on the symptoms of depression. A total of 46 studies met the eligibility criteria. Of these, 36 were intervention trials and 10 were observational studies. A meta-analysis of 36 clinical trials involving a total of 2788 participants was performed. The results showed a statistically significant effect of flavonoids on depressive symptoms (mean difference = −1.65; 95% C.I., −2.54, −0.77; p < 0.01). Five of the 10 observational studies included in the systematic review reported significant results, suggesting that a higher flavonoid intake may improve symptoms of depression. Further studies are urgently required to elucidate whether causal and mechanistic links exist, along with substantiation of functional brain changes associated with flavonoid consumption.

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Telomeres are protective caps at the end of eukaryotic chromosomes, whose length is correlated with health and lifespan. Telomere attrition is a common feature of the aging process and can be accelerated by oxidative stress and chronic inflammation. Various nutrients influence the telomere length, partially due to their antioxidant and anti-inflammatory properties. The aim of this review was to meta-analytically assess the effect of omega-3 fatty acids on the telomere length. We searched four databases (PubMed, Web of Sciences, Scopus, and the Cochrane Library) from inception until November 2021. Of 573 records, a total of 5 clinical trials were included for the quantitative meta-analysis, comprising a total of 337 participants. The results revealed an overall beneficial effect of omega-3 fatty acids on the telomere length (mean difference = 0.16; 95% CI, 0.02, 0.30; p = 0.02). Despite a limited number of studies, the available evidence suggests that omega-3 fatty acids may positively affect the telomere length. However, larger clinical trials are needed to confirm our findings, along with studies aimed to clarify the underlying molecular mechanisms.

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