Dietary Interventions with Polyphenols in Osteoarthritis: A Systematic Review Directed from the Preclinical Data to Randomized Clinical Studies

Diet modification reduces pain and improves function in adults with osteoarthritis: a systematic review

BACKGROUND

The effect of dietary modifications on pain and joint function in adults with osteoarthritis (OA) is an emerging area of study. This systematic review aimed to evaluate if adults with OA who consume diets with a higher proportion of plant phenols and omega-3 fatty acids would have less pain and improved joint function than those with a higher proportion of saturated fatty acids, omega-6 fatty acids and refined carbohydrates.

METHODS

Database searches of CINAHL (EBSCO), Clinical Trials (NIH-NLM), Cochrane Library (Wiley), Dissertation & Thesis Global (ProQuest), Embase (Elsevier), Medline (OVID), PubMed (NLM), Scopus (Elsevier), Web of Sciences (Clarivate) for clinical trials identified 7763 articles published between January 2015 and May 2023. After an independent review of the articles, seven randomised clinical trials and one nonrandomised clinical trial were included in the analysis. Because of the heterogeneity of the outcome measures, a meta-analysis was not possible.

RESULTS

Participants who were instructed to consume high-phenol/high-omega-3 fatty acid diets reported significant improvements in pain and physical function scores. The greatest improvement was reported by those who consumed a diet that had the most omega-3 fatty acids.

CONCLUSION

Because of the high risk of bias, the strength of the evidence is limited. However, there is evidence that counselling adults with OA to replace refined grains and processed foods with whole plant foods, fish and plant oils may have a favourable effect on pain and physical function. Routine follow-up care regarding these diet modifications may be necessary to ensure adherence to this therapy.

Effects of Functional and Nutraceutical Foods in the Context of the Mediterranean Diet in Patients Diagnosed with Breast Cancer

Several studies report that breast cancer survivors (BCS) tend to have a poor diet, as fruit, vegetable, and legume consumption is often reduced, resulting in a decreased intake of nutraceuticals. Moreover, weight gain has been commonly described among BCS during treatment, increasing recurrence rate and mortality. Improving lifestyle and nutrition after the diagnosis of BC may have important benefits on patients' general health and on specific clinical outcomes. The Mediterranean diet (MD), known for its multiple beneficial effects on health, can be considered a nutritional pool comprising several nutraceuticals: bioactive compounds and foods with anti-inflammatory and antioxidant effects. Recent scientific advances have led to the identification of nutraceuticals that could amplify the benefits of the MD and favorably influence gene expression in these patients. Nutraceuticals could have beneficial effects in the postdiagnostic phase of BC, including helping to mitigate the adverse effects of chemotherapy and radiotherapy. Moreover, the MD could be a valid and easy-to-follow option for managing excess weight. The aim of this narrative review is to evaluate the recent scientific literature on the possible beneficial effects of consuming functional and nutraceutical foods in the framework of MD in BCS.

A standardized nutraceutical supplement contributes to pain relief, improves quality of life and regulates inflammation in knee osteoarthritis patients; A randomized clinical trial

Osteoarthritis (OA) is a degenerative disease of the joints that affects greatly the elderly population and the health care systems and is on the increase due to aging and obesity. Interventions aim at palliative care and pharmaceutical therapies entail serious adverse events. Whereas polyphenols constitute a promising holistic approach in the arsenal of physicians, trials investigating biomarkers and questionnaires are scarce. As such, a randomized controlled trial (RCT) was conducted to evaluate the potency of a standardized polyphenolic supplement in the management of systemic inflammation, oxidative stress, pain and general quality of life (QoL) in patients with osteoarthritis. Sixty subjects were randomized to receive either a polyphenol supplement (curcuma phospholipid, rosemary extract, resveratrol, ascorbic acid), or an active comparator (ascorbic acid) twice, daily for 12 weeks. The group that received the polyphenols exhibited significantly lower symptoms of pain and improved physical function and QoL as it was depicted by validated questionnaires, compared to the control group. Furthermore, post intervention, inflammation was restrained in the polyphenol group. Since systemic inflammation promotes local inflammation, the decrease of pain herein might be attributed to the attenuation of systemic inflammation by the polyphenols.

The protective activity of natural flavonoids against osteoarthritis by targeting NF-κB signaling pathway

Osteoarthritis (OA) is a typical joint disease associated with chronic inflammation. The nuclear factor-kappaB (NF-κB) pathway plays an important role in inflammatory activity and inhibiting NF-κB-mediated inflammation can be a potential strategy for treating OA. Flavonoids are a class of naturally occurring polyphenols with anti-inflammatory properties. Structurally, natural flavonoids can be divided into several sub-groups, including flavonols, flavones, flavanols/catechins, flavanones, anthocyanins, and isoflavones. Increasing evidence demonstrates that natural flavonoids exhibit protective activity against the pathological changes of OA by inhibiting the NF-κB signaling pathway. Potentially, natural flavonoids may suppress NF-κB signaling-mediated inflammatory responses, ECM degradation, and chondrocyte apoptosis. The different biological actions of natural flavonoids against the NF-κB signaling pathway in OA chondrocytes might be associated with the differentially substituted groups on the structures. In this review, the efficacy and action mechanism of natural flavonoids against the development of OA are discussed by targeting the NF-κB signaling pathway. Potentially, flavonoids could become useful inhibitors of the NF-κB signaling pathway for the therapeutic management of OA.

Potential role of nutraceuticals via targeting a Wnt/β-catenin and NF-κB pathway in treatment of osteoarthritis

Osteoarthritis (OA) is a disease due to the aging of the articular cartilage, a post-mitotic tissue that stays functioning until primary homeostatic processes fail. Because of pain and disability, OA significantly influences national healthcare expenses and patient quality of life. It is a whole-joint illness characterized by inflammatory and oxidative signaling pathways and significant epigenetic alterations that cause cartilage extracellular matrix degradation. The canonical Wnt pathway (Wnt/β-catenin pathway) and nuclear factor kappa B (NF-κB) signaling pathways may function in joint tissues by modulating the activity of synovial cells, osteoblasts, and chondrocytes. However, finding innovative ways to treat osteoarthritis and get the joint back to average balance is still a struggle. Nutraceuticals are dietary supplements that promote joint health by balancing anabolic and catabolic signals. New therapeutic methods for OA treatment have been developed based on many research findings that show nutraceuticals have strong anti-inflammation, antioxidant, anti-bone resorption, and anabolic properties. For the treatment of osteoarthritis, we explore the possible involvement of nutraceuticals that target the Wnt/β-catenin and NF-κB pathways. PRACTICAL APPLICATIONS: In keeping with the aging population, osteoarthritis is becoming more widespread. In this extensive research, we studied the role of the Wnt/β-catenin and NF-κB pathway in OA formation and progression. Nutraceuticals that target these OA-related signaling pathways are a viable therapy option. Wnt/β-catenin and NF-κB signaling pathway are inhibited by polyphenols, flavonoids, alkaloids, and vitamins from the nutraceutical category, making them possible therapeutic drugs for OA therapy.

Valorization of Grape Pomace and Berries as a New and Sustainable Dietary Supplement: Development, Characterization, and Antioxidant Activity Testing

Grape pomace and berries represent natural sources of phytochemicals that can increase the quality of life of consumers by contributing to the prevention of chronic diseases; thus, the development of a dietary supplement was necessary. The raw material (r.m.) used for the development of the dietary supplement consisted of dried and powdered bilberries (Vaccinium myrtillus L.), red currants (Ribes rubrum L.), and red fermented pomaces (Vitis vinifera L.) from Feteasca Neagra and Cabernet Sauvignon cultivars. The particle size distribution, powder flow, total phenolic content (TPC), HPLC-DAD phenolic profile assessment, and radical scavenging assay (RSA) were employed for the analysis of the raw material. After encapsulation, the average mass and uniformity of mass, the disintegration, and the uniformity of content for the obtained capsules were performed to obtain a high-quality dietary supplement. All the assays performed complied to the compendial requirements and the TPC was determined at 9.07 ± 0.25 mg gallic acid equivalents/g r.m. and RSA at 48.32 ± 0.74%. The highest quantities of phenolic compounds determined were 333.7 ± 0.50 µg/g r.m. for chlorogenic acid, followed by rutin, ferulic acid, and (+)-catechin with 198.9 ± 1.60 µg/g r.m., 179.8 ± 0.90 µg/g r.m. and 118.7 ± 0.75 µg/g r.m., respectively. The results of this study can be used for the manufacturing and assessing of pilot scale-up capsule batches and thinking of quality assurance, we recommend that the industrial batch extracts should be standardized in polyphenols, and the manufacturing process should be validated.

Higher dietary phytochemical index is associated with lower odds of knee osteoarthritis

Previous studies have shown that adherence to dietary patterns rich in plant-based foods may reduce the odds of osteoarthritis; however, limited data are available on the association of consumption of diets rich in phytochemicals and odds of knee osteoarthritis (KOA). In this case–control study conducted in Iran, we aimed to investigate whether a higher dietary phytochemical index (DPI) is associated with decreased odds of having KOA. A total of 124 cases aged 20–60 years diagnosed with bilateral primary KOA according to the American College of Rheumatology criteria and 124 controls frequency-matched on age, sex, and body mass index (BMI) were included in the study. A validated food frequency questionnaire (FFQ) was used to collect information on dietary intakes. To calculate DPI scores, the dietary energy derived from foods rich in phytochemicals (kcal) was divided by the participant’s total daily energy intake (kcal). Patients with KOA had lower intakes of dietary fiber (P = 0.004), vitamin A (P = 0.007), vitamin C (P = 0.001), and folate (P = 0.021) compared to controls. In the crude model, individuals in the third tertile of DPI had 65% lower odds of having KOA compared to those in the first tertile (OR 0.35, 95% CI 0.19 to 0.67, P-trend = 0.001). After adjustment for potential confounders, including age, sex, physical activity, smoking, and supplement use, this inverse association remained significant (OR 0.37, 95% CI 0.19 to 0.73, P-trend = 0.004). After further adjustment for BMI, this inverse association between DPI and odds of KOA also remained significant (OR 0.35, 95% CI 0.18 to 0.69, P-trend = 0.003). These findings suggest that adherence to a phytochemical-rich diet, as indicated by the increasing DPI score, is associated with lower odds of KOA.

A literature review on plant-based foods and dietary quality in knee osteoarthritis

This literature review summarizes the role of plant-based foods and diet quality in osteoarthritis, particularly knee osteoarthritis, in observational studies and clinical trials published during 2015- 2020. The included studies have suggested favorable results on reducing the prevalence, pain, and cartilage changes related to osteoarthritis and inflammatory and oxidation markers such as inter- leukin-1, interleukin-6, tumor necrosis factor, and lipid peroxidation. Due to the lack of large lon- gitudinal cohorts to study whole foods or diets concerning knee osteoarthritis, findings from the cross-sectional studies or clinical trials require further validation, particularly in well-designed clinical trials and a more extended follow-up period. Potential mechanisms on the role of plant-based foods in body weight, inflammation, and microbiome were explored to explain their protective associations with osteoarthritis. However, most evidence examining the relationship between the microbiome and osteoarthritis joint pain is conducted in preclinical animal studies, and few observational studies show a positive association between Streptococcus species and local joint inflammation in the knee. Given the close links of plant-based foods on obesity, inflammation, and microbiome, data on the role of whole foods or diets in the change in knee osteoarthritis pain through the lens of microbial composition can provide more certainty regarding the utilization of microbiome as a potential thera- peutic target.

Effect of Dietary Polyphenols on Osteoarthritis—Molecular Mechanisms

Osteoarthritis is a common crippling and degenerative disease resulting in irreversible functional changes due to damage of the cartilage and other tissues of the joint. With limited safe and effective pharmaceutical treatments, the demand and use for alternative therapeutic approaches with symptomatic relief for OA patients have increased. Clinical, pre-clinical, and in vitro studies have demonstrated that polyphenols can exert pain-relieving symptoms coupled with increased functional capacity in OA models. This review will highlight studies carried out in the last five years to define the efficacies and underlying mechanisms in polyphenols such as quercetin, resveratrol, curcumin, epigallocatechin-3-gallate, rosmarinic acid, genistein, ginger, berries, silver fir, pine bark, and Boswellia. Most of these studies indicate that polyphenols exhibit their beneficial roles through regulating changes at the biochemical and molecular levels, inducing or inhibiting various signaling pathways related to inflammation and oxidative stress. Polyphenols have also been implicated in modulating microRNA at the posttranscriptional level to counteract OA pathogenesis.

Inhibitory activities of grape bioactive compounds against enzymes linked with human diseases

A quest for identification of novel, safe and efficient natural compounds, as additives in the modern food and cosmetic industries, has been prompted by concerns about toxicity and side effects of synthetic products. Plant phenolic compounds are one of the most documented natural products due to their multifarious biological applications. Grape (Vitis vinifera) is an important source of phenolic compounds such as phenolic acids, tannins, quinones, coumarins and, most importantly, flavonoids/flavones. This review crisply encapsulates enzyme inhibitory activities of various grape polyphenols towards different key human-ailment-associated enzymes: xanthine oxidase (gout), tyrosinase (hyperpigmentation), α-amylase and α-glucosidase (diabetes mellitus), pancreatic lipase (obesity), cholinesterase (Alzheimer's disease), angiotensin i-converting enzymes (hypertension), α-synuclein (Parkinson's disease) and histone deacetylase (various diseases). The review also depicts the enzyme inhibitory mechanism of various grape polyphenols and briefly discusses their stature as potential therapeutic and drug development candidates. KEY POINTS: • Nineteen major bioactive polyphenols from the grape/grape products and their disease targets are presented • Sixty-two important polyphenols as enzyme inhibitors from grape/grape products are presented • A thorough description and graphical presentation of biological significance of polyphenols against various diseases.

Polygenetic Variants Related to Osteoarthritis Risk and Their Interactions with Energy, Protein, Fat, and Alcohol Intake in Adults in a Large Cohort

Osteoarthritis (OA) is increasing globally, especially among elderly Asian women, and its increase may be due to the interaction between genetic factors and lifestyle. This study tested the hypothesis that polygenetic variants associated with OA risk interacted with lifestyle in adults over 40 years in the Ansan–Ansung cohort. Genetic variants were chosen through a genome-wide association study with OA participants (case; n = 580) and controls without arthritis (n = 4850). Genetic variants with interactions were selected by a generalized multifactor dimensionality reduction. The best model’s polygenic risk scores (PRS) were calculated by summing the number of risk alleles in the selected genetic variants. The best five single nucleotide polymorphism (SNP) model included AIG1_rs6570550, COX10_rs62054459, DLG2_rs148643344, SOX5_rs73283615, and PLXNA4_rs1472529430, while IL12A_ rs1491318751 was added to the five-SNP model to produce a six-SNP model. Only COX10_rs62054459 in subcutaneous and visceral adipose tissue was associated with COX10 protein expression. The participants, having high-PRS from the five-SNP and six-SNP models, were at a higher OA risk than those with low-PRS by 3.88 and 4.42 times, respectively. The PRS was not associated with metabolic syndrome or with the insulin resistance index (HOMA-IR). Energy, protein, fat, alcohol, and a Western-style diet intake interacted with the PRS to influence OA risk (p = 0.005, 0.042, and 0.021, respectively). In the high energy and alcohol intake and low protein, fat, Western-style diet intake, the participants with a high-PRS had a higher incidence of OA than those with low-PRS. In conclusion, the adults with a high-PRS were at a higher OA risk. Particularly, adults with high PRS should have a lower energy intake, higher WSD containing higher protein and fat intake, and moderate alcohol intake to alleviate OA risk. These results can be applied to personalized nutrition plans to decrease OA risk.

Phytochemicals Mediate Autophagy Against Osteoarthritis by Maintaining Cartilage Homeostasis

Osteoarthritis (OA) is a common degenerative joint disease and is a leading cause of disability and reduced quality of life worldwide. There are currently no clinical treatments that can stop or slow down OA. Drugs have pain-relieving effects, but they do not slow down the course of OA and their long-term use can lead to serious side effects. Therefore, safe and clinically appropriate long-term treatments for OA are urgently needed. Autophagy is an intracellular protective mechanism, and targeting autophagy-related pathways has been found to prevent and treat various diseases. Attenuation of the autophagic pathway has now been found to disrupt cartilage homeostasis and plays an important role in the development of OA. Therefore, modulation of autophagic signaling pathways mediating cartilage homeostasis has been considered as a potential therapeutic option for OA. Phytochemicals are active ingredients from plants that have recently been found to reduce inflammatory factor levels in cartilage as well as attenuate chondrocyte apoptosis by modulating autophagy-related signaling pathways, which are not only widely available but also have the potential to alleviate the symptoms of OA. We reviewed preclinical studies and clinical studies of phytochemicals mediating autophagy to regulate cartilage homeostasis for the treatment of OA. The results suggest that phytochemicals derived from plant extracts can target relevant autophagic pathways as complementary and alternative agents for the treatment of OA if subjected to rigorous clinical trials and pharmacological tests.

The Role of Nutraceuticals in Osteoarthritis Prevention and Treatment: Focus on n-3 PUFAs

Osteoarthritis (OA) is a disease caused by joint degeneration with massive cartilage loss, and obesity is among the risk factors for its onset, though the pathophysiological mechanisms underlying the disease and better therapeutic approach still remain to be assessed. In recent years, several nutraceutical interventions have been investigated in order to define better solutions for preventing and treating OA. Among them, polyunsaturated fatty acids (n-3 PUFAs) appear to represent potential candidates in counteracting OA and its consequences, due to their anti-inflammatory, antioxidant, and chondroinductive effects. PUFAs have been found to counteract the onset and progression of OA by reducing bone and cartilage destruction, inhibiting proinflammatory cytokine release, reactive oxygen species (ROS) generation, and the NF-κB pathway's activation. Moreover, a diet rich in n-3 PUFAs and their derivatives (maresins and resolvins) demonstrates beneficial effects on associated pain reduction. Finally, it has been shown that together with the anti-inflammatory and antioxidant properties of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, their antiapoptotic and antiangiogenic effects contribute in reducing OA development. The present review is aimed at assessing evidence suggesting the potential benefit of nutraceutical supplementation with PUFAs in OA management according to their efficacy in targeting relevant pathophysiological mechanisms responsible for inflammation and joint destruction processes, and this may represent a novel and potentially useful approach in OA prevention and treatment. For that purpose, a PubMed literature survey was conducted with a focus on some in vitro and in vivo studies and clinical trials from 2015 to 2020.

Phytochemical Analysis and Anti-Inflammatory Activity of Different Ethanolic Phyto-Extracts of Artemisia annua L

Artemisia annua L. (AA) has shown for many centuries important therapeutic virtues associated with the presence of artemisinin (ART). The aim of this study was to identify and quantify ART and other secondary metabolites in ethanolic extracts of AA and evaluate the biological activity in the presence of an inflammatory stimulus. In this work, after the extraction of the aerial parts of AA with different concentrations of ethanol, ART was quantified by HPLC and HPLC-MS. In addition, anthocyanins, flavanols, flavanones, flavonols, lignans, low-molecular-weight phenolics, phenolic acids, stilbenes, and terpenes were identified and semi-quantitatively determined by UHPLC-QTOF-MS untargeted metabolomics. Finally, the viability of human neuroblastoma cells (SH-SY5Y) was evaluated in the presence of the different ethanolic extracts and in the presence of lipopolysaccharide (LPS). The results show that ART is more concentrated in AA samples extracted with 90% ethanol. Regarding the other metabolites, only the anthocyanins are more concentrated in the samples extracted with 90% ethanol. Finally, ART and all AA samples showed a protective action towards the pro-inflammatory stimulus of LPS. In particular, the anti-inflammatory effect of the leaf extract of AA with 90% ethanol was also confirmed at the molecular level since a reduction in TNF-α mRNA gene expression was observed in SH-SY5Y treated with LPS.