Four-week ingestion of blood orange juice results in measurable anthocyanin urinary levels but does not affect cellular markers related to cardiovascular risk: a randomized cross-over study in healthy volunteers

Bioavailability of Anthocyanins: Whole Foods versus Extracts

Anthocyanins have gained significant popularity in recent years for their diverse health benefits, yet their limited bioavailability poses a challenge. To address this concern, technologies have emerged to enhance anthocyanin concentration, often isolating these compounds from other food constituents. However, the extent to which isolated anthocyanins confer health benefits compared to their whole-food counterparts remains unclear. This review explores the current literature on anthocyanin bioavailability and metabolism in the body, with a focus on comparing bioavailability when consumed as extracts versus whole foods rich in anthocyanins, drawing from in vitro, in vivo, and human clinical studies. While direct comparisons between anthocyanin bioavailability in whole foods versus isolates are scarce, prevailing evidence favours whole-food consumption over anthocyanin extracts. Further clinical investigations, preferably with direct comparisons, are needed to validate these findings and elucidate the nuanced interplay between anthocyanins and food matrices, informing future research directions and practical recommendations.

Effects of Vaccinium berries (blueberries, cranberries and bilberries) on oxidative stress, inflammation, exercise performance, and recovery - a systematic review

Exercise-induced muscle damage is common in athletes and recreational exercisers and can lead to muscle soreness, weakness, and impaired muscle function. The precise mechanisms are unclear but oxidative stress and inflammation are thought to play a role. (Poly)phenols are substances abundant in Vaccinium berries that have been suggested to possess antioxidant and anti-inflammatory effects that could help improve exercise performance and/or recovery from exercise. The objective of this systematic review was to evaluate the benefits of Vaccinium berry supplementation on exercise performance and recovery, as well as on exercise-induced oxidative and inflammatory biomarkers in healthy individuals. A comprehensive search was conducted in PubMed, ProQuest Medline, Web of Science, Cochrane Library, and Scopus. Studies were included if the participants were healthy individuals who were supplemented with any Vaccinium berry or Vaccinium berry-based products in comparison to a control group. Of the 13 articles included in this review, no significant differences in the exercise performance were found and only one study reported benefits for markers of recovery. Interleukins and c-reactive protein were the most frequently reported biomarkers, but there was limited evidence that Vaccinium berry supplementation impacted them post-exercise. Most studies were of high quality and showed a low risk of bias. Vaccinium berry supplementation is not effective in modulating markers of exercise-induced inflammation and oxidative distress in healthy individuals; nevertheless, more studies are required to evaluate their effects on exercise performance and recovery in this population.

Distribution, Antioxidant Capacity, Bioavailability and Biological Properties of Anthocyanin Pigments in Blood Oranges and Other Citrus Species

Anthocyanins are natural pigments that give a red, purple, and blue color to many plant, flower, fruit, and vegetable species. Their presence within the genus Citrus was first reported in 1916, and it is well-known that the red color of the flesh and rind of blood (red or pigmented) oranges (Citrus sinensis L. Osbeck) is due to the presence of anthocyanins. They are also present in the young shoots, flowers, and peel of lemon (Citrus limon (L.) Burm. f.), citron (Citrus medica L.), and other citrus species. Since then, the scientific community has expressed increasing interest in studying their profile and distribution, with many published studies focused on the quali-quantitative pattern in the different vegetative tissues belonging to the genus Citrus. Moreover, with the discovery of their relevant antioxidant activity, owing to their ability to capture free radicals, much research has been performed in the last two decades on their radical scavenging power, in vitro and in vivo biological properties, and anticarcinogenic capacity, also focusing attention on their bioavailability for humans. The present work is intended as a comprehensive review of the advances in scientific research on anthocyanin pigments naturally occurring within the genus Citrus, including their natural distribution, antioxidant capacity, bioavailability, and biological value and properties. The scientific evidence herein reported can be used to further increase the knowledge of this class of compounds and represents a valuable and comprehensive contribution to promoting anthocyanin-rich citrus fruit consumption as a healthy dietary habit.

Dietary Effects of Anthocyanins in Human Health: A Comprehensive Review

In recent years, the consumption of natural-based foods, including beans, fruits, legumes, nuts, oils, vegetables, spices, and whole grains, has been encouraged. This fact is essentially due to their content in bioactive phytochemicals, with the phenolic compounds standing out. Among them, anthocyanins have been a target of many studies due to the presence of catechol, pyrogallol, and methoxy groups in their chemical structure, which confer notable scavenging, anti-apoptotic, and anti-inflammatory activities, being already recommended as supplementation to mitigate or even attenuate certain disorders, such as diabetes, cancer, and cardiovascular and neurological pathologies. The most well-known anthocyanins are cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside. They are widespread in nature, being present in considerable amounts in red fruits and red vegetables. Overall, the present review intends to discuss the most recent findings on the potential health benefits from the daily intake of anthocyanin-rich foods, as well as their possible pharmacological mechanisms of action. However, before that, some emphasis regarding their chemical structure, dietary sources, and bioavailability was done.

Polyphenols and Human Health: The Role of Bioavailability

Polyphenols are a group of phytochemicals with potential health-promoting effects. They are classified as flavonoid (flavonols, flavanols, flavones, flavanones, isoflavones, and anthocyanins) and non-flavonoid molecules (phenolic acids, hydroxycinnamic acids, lignans, stilbenes, and tannins). Although an increasing number of trials have shown a correlation among polyphenol consumption and a reduction in risk factors for chronic diseases, discrepancies in explaining their positive effects have been found in terms of the bioavailability. In fact, polyphenols show a low bioavailability due to several factors: interaction with the food matrix, the metabolic processes mediated by the liver (phase I and II metabolism), intestine and microbiota. On the other hand, the biological activities of phenol compounds may be mediated by their metabolites, which are produced in vivo, and recent studies have confirmed that these molecules may have antioxidant and anti-phlogistic properties. This review discusses the studies performed in vivo, which consider the polyphenol bioavailability and their different food sources. Factors influencing the biological effects of the main classes of polyphenols are also considered.

Skin toxicity following radiotherapy in patients with breast carcinoma: is anthocyanin supplementation beneficial?

BACKGROUND

The EU-supported ATHENA project stems from a previous study suggesting that moderate wine consumption reduced the side-effects of radiotherapy (RT) in breast cancer patients, an effect possibly due to non-alcoholic anthocyanin fractions of wine.

OBJECTIVE

To evaluate the role of anthocyanins on RT skin side effects in breast cancer patients.

METHODS

Randomized, controlled, double-blind clinical trial. Patients were assigned to an intensity modulated radiation therapy (IMRT) either for three or five weeks, then randomized to receive three times a day a water-soluble anthocyanin (125 mg)-rich extract of corn cob or a placebo. Supplementation started one week before till the end of RT. Skin characteristics were detected by a standardized, non-invasive Cutometer® dual-MPA580, providing quantitative indices of skin maximal distensibility (R0), elasticity (R2, R5, R7) and viscoelasticity (R6); a Mexameter® MX18 probe evaluated the skin erythema (Er) and melanin (M). Measures were performed before (T0), at the end of RT and of supplementation (T1), and 1, 6 and 12 months after RT (T2-T4). Acute and late skin toxicity were scored according to the RTOG/EORTG scale. Selected biomarkers were measured at T0 and T1.

RESULTS

193 patients previously assigned to 3- or 5-week RT schedules were randomized to either anthocyanin (97) or placebo (96) supplementation. RT induced changes in skin parameters: R0, R2, R5 and R7 decreased, while R6 increased; the changes in R0 and R6 continued in the same direction up to one year, while the others recovered towards basal values; Er and M peaked at T1 and T2, respectively, and returned to basal values at T4. Comparable skin changes were apparent in anthocyanin and placebo groups. A moderate RT-induced increase in total and HDL cholesterol and triglycerides was prevented by anthocyanins.

CONCLUSIONS

Anthocyanin supplementation did not prevent RT-induced local skin toxicity. The supplementation was well tolerated and safe.

Anthocyanins: A Comprehensive Review of Their Chemical Properties and Health Effects on Cardiovascular and Neurodegenerative Diseases

Anthocyanins are a class of water-soluble flavonoids widely present in fruits and vegetables. Dietary sources of anthocyanins include red and purple berries, grapes, apples, plums, cabbage, or foods containing high levels of natural colorants. Cyanidin, delphinidin, malvidin, peonidin, petunidin, and pelargonidin are the six common anthocyanidins. Following consumption, anthocyanin, absorption occurs along the gastrointestinal tract, the distal lower bowel being the place where most of the absorption and metabolism occurs. In the intestine, anthocyanins first undergo extensive microbial catabolism followed by absorption and human phase II metabolism. This produces hybrid microbial-human metabolites which are absorbed and subsequently increase the bioavailability of anthocyanins. Health benefits of anthocyanins have been widely described, especially in the prevention of diseases associated with oxidative stress, such as cardiovascular and neurodegenerative diseases. Furthermore, recent evidence suggests that health-promoting effects attributed to anthocyanins may also be related to modulation of gut microbiota. In this paper we attempt to provide a comprehensive view of the state-of-the-art literature on anthocyanins, summarizing recent findings on their chemistry, biosynthesis, nutritional value and on their effects on human health.

Anthocyanins: From Sources and Bioavailability to Cardiovascular-Health Benefits and Molecular Mechanisms of Action

Anthocyanins are phytochemicals widely found in plant foods, with berries and fruit-derived beverages as the main dietary sources. Accumulating evidence suggests the positive role of anthocyanins in preserving cardiovascular health. Epidemiological data show an association between anthocyanin intake and lower risk of myocardial infarction and cardiovascular-disease-related mortality. Clinical studies report the beneficial effects of the consumption of different anthocyanin-rich sources on surrogate markers of cardiovascular risk. Animal and in vitro evidence suggest the protective role of anthocyanins in dysfunctions related to the development of cardiovascular diseases. Still, the underlying molecular mechanisms of anthocyanin action seem complex and are not entirely clear. This review aims to give a comprehensive update on anthocyanins and their cardioprotective properties. It provides information on their sources; quantities consumed through diet; absorption; bioavailability; cardiovascular properties; and underlying mechanisms of action, including their effects on gene and protein expression and their interactions with cell-signaling pathways and miRNAs.

4-Week consumption of anthocyanin-rich blood orange juice does not affect LDL-cholesterol or other biomarkers of CVD risk and glycaemia compared with standard orange juice: a randomised controlled trial

Elevated circulating cholesterol levels are a risk factor for CVD which is also associated with sub-optimal vascular function. There is emerging evidence that anthocyanins can cause beneficial cardio-protective effects by favourably modulating lipoprotein profiles. We compared the effects of blood orange juice which is rich in anthocyanins and blonde orange juice without anthocyanins on LDL-cholesterol and other biomarkers of CVD risk, vascular function and glycaemia. In all, forty-one participants (aged 25-84 years) with a waist circumference >94 cm (men) and >80 cm (women) completed a randomised, open label, two-arm cross-over trial. For 28 d participants ingested (i) 500 ml blood orange juice providing 50 mg anthocyanins/d and (ii) 500 ml blonde orange juice without anthocyanins. There was a minimum 3-week washout period between treatments. LDL-cholesterol and other biomarkers associated with CVD risk and glycaemia were assessed at the start and end of each treatment period. No significant differences were observed in total, HDL- and LDL-cholesterol, TAG, glucose, fructosamine, nitric oxide, C-reactive protein, aortic systolic blood pressure and diastolic blood pressure or carotid-femoral and brachial-ankle pulse wave velocity after 28 d ingestion of blood orange juice compared with standard orange juice. The lack of effect on LDL-cholesterol may be due to the modest concentration of anthocyanins in the blood orange juice.

Contribution of anthocyanin-rich foods in obesity control through gut microbiota interactions

Obesity is characterized by low-grade inflammation and a number of metabolic disorders. Distal gut microbes' content (microbiota) is not yet fully understood but evidence shows that it is influenced by internal and external factors that modulate its composition and function. The evidence that gut microbiota composition can differ between healthy and obese individuals, as well as for those who maintain specific dietary habits, has led to the study of this environmental factor as a key link between the pathophysiology of obesity and gut microbiota. Data obtained about the role of anthocyanins (ACNs) in microbiota may lead to different strategies to manipulate bacterial populations and promote health. Anthocyanins have been identified as modulators of gut microbiota that contribute to obesity control and these bioactive compounds should be considered to have a prebiotic action. This review addresses the relevance of knowledge about the influence of anthocyanins-rich food consumption on microbiota, and their health-promoting potential in the pathophysiology of obesity. © 2017 BioFactors, 43(4):507-516, 2017.

Metabolic Effects of Berries with Structurally Diverse Anthocyanins

Overconsumption of energy dense foods and sedentary lifestyle are considered as major causes of obesity-associated insulin resistance and abnormal glucose metabolism. Results from both cohort studies and randomized trials suggested that anthocyanins from berries may lower metabolic risks, however these reports are equivocal. The present study was designed to examine effects of six berries with structurally diverse anthocyanin profiles (normalized to 400 µg/g total anthocyanin content) on development of metabolic risk factors in the C57BL/6 mouse model of polygenic obesity. Diets supplemented with blackberry (mono-glycosylated cyanidins), black raspberry (acylated mono-glycosylated cyanidins), blackcurrant (mono- and di-glycosylated cyanidins and delphinidins), maqui berry (di-glycosylated delphinidins), Concord grape (acylated mono-glycosylated delphinidins and petunidins), and blueberry (mono-glycosylated delphinidins, malvidins, and petunidins) showed a prominent discrepancy between biological activities of delphinidin/malvidin-versus cyanidin-type anthocyanins that could be explained by differences in their structure and metabolism in the gut. Consumption of berries also resulted in a strong shift in the gastrointestinal bacterial communities towards obligate anaerobes that correlated with decrease in the gastrointestinal luminal oxygen and oxidative stress. Further work is needed to understand mechanisms that lead to nearly anoxic conditions in the gut lumens, including the relative contributions of host, diet and/or microbial oxidative activity, and their implication to human health.

Dietary anthocyanins and health: data from FLORA and ATHENA EU projects

Adherence to a 'Mediterranean diet' has been shown to be beneficial to human health. Fruit and vegetables represent some of the main components of the Mediterranean diet and their role has been increasingly considered in the process of preventing or reducing the risk of chronic degenerative diseases, such as cerebrovascular or coronary heart disorders, cancer and neurodegenerative diseases. To investigate the beneficial effect of these dietary compounds, two EU-funded projects were conducted during the last 10 years. Their results from experimental models suggest that dietary anthocyanin enrichment is beneficial against a number of ischemic and degenerative conditions. On the other hand, human studies demonstrated that anthocyanin supplementation can counteract the inflammatory response to stress conditions, such as a fatty meal. Moreover, an intervention trial in patients with breast cancer undergoing radiotherapy is presently testing the possible beneficial effect of the administration of a product enriched in anthocyanins on the inflammatory response to radiation and on its consequent skin toxicity, as well as on systemic low-grade inflammation reaction.

Anthocyanins in obesity-associated thrombogenesis: a review of the potential mechanism of action

Platelet dysfunction, oxidative stress and dyslipidemia are important contributors to pro-thrombotic progression particularly in obese and hyper-cholesterolemic populations.

Black Currant Anthocyanins Attenuate Weight Gain and Improve Glucose Metabolism in Diet-Induced Obese Mice with Intact, but Not Disrupted, Gut Microbiome

Black currant (Ribes nigrum L.) is a rich source of anthocyanins; however, the relationship between their apparently limited bioavailability and significant protection against metabolic pathologies is poorly understood. This study examined the gastrointestinal distribution of black currant anthocyanins and their phenolic acid metabolites in lean and diet-induced obese mice with healthy and antibiotic-disrupted microbiomes. Daily consumption of low- or high-fat diet supplemented with 1% black currant powdered extract (32% anthocyanins) for 8 weeks reduced body weight gain and improved glucose metabolism only in mice with the intact gut microbiome. Administration of antibiotic cocktail resulted in a 16-25-fold increase (P < 0.001) in anthocyanin content of feces, and cyanidin-based anthocyanins showed the largest increase in fecal content upon disruption of gut microbiome (92.3 ± 16.3 vs 4719 ± 158 μg/g feces), indicating their high susceptibility to microbial degradation in the gut. A 3-fold enrichment (P < 0.05) in gallic over protocatechuic acid was observed in the jejunum of both intact and antibiotic-treated animals, suggesting that this effect was likely independent of their gut microbiome status. Taken together, the data clearly demonstrate that gut microbiome and the type of the anthocyanin aglycone moiety can alter the protective effect of anthocyanins against obesity and associated insulin resistance.

Orange juice intake during a fatty meal consumption reduces the postprandial low-grade inflammatory response in healthy subjects

BACKGROUND AND AIMS

Evidence associates polyphenol-rich foods to reduction of low-grade inflammation and mortality for cardiovascular disease, the mechanisms underlying such effects being still unclear. Consumption of a fatty meal by healthy volunteers induces rapid and reversible low-grade inflammation. The aim of the present study was to evaluate the effect of orange juice on cellular modifications induced by a fatty meal.

METHODS AND RESULTS

18 apparently healthy subjects consumed a fatty meal, during which they drunk orange juice, either blond or red, or water, according to a randomized cross-over design. Two hours after the end of the fatty meal, both white blood cell (WBC) and platelet counts significantly increased (12.5 and 5%, respectively), while mean platelet volume decreased and a 25% release of myeloperoxidase (MPO) from polymorphonuclear leukocyte occurred. Both juices significantly prevented WBC increase and MPO degranulation, in respect to control. Triglycerides significantly increased (42%) after the fatty meal, but at a lower extent when red orange juice was consumed with the meal (20%), in respect to blond orange juice or control. This effect was statistically significant in the subgroup of 8 subjects with hypertriglyceridemia. Vascular stiffness (augmentation index), measured by Endo-PAT2000, significantly decreased after the meal only in conjunction with red orange juice.

CONCLUSION

In healthy subjects the concomitant intake of orange juice may prevent the low-grade inflammatory reaction induced by a fatty meal, at cellular and possibly at vascular function levels. The relative role of different polyphenols on the observed effects of orange juices remains to be established.

Dietary anthocyanin-rich plants: biochemical basis and recent progress in health benefits studies

Anthocyanins are one type of flavonoid phytopigment. Although the role of anthocyanins as a functional food factor remains relatively less established than that of other flavonoids, progress in this area has been made at the molecular level in recent years. This review discusses the potential health benefits of plant-derived anthocyanin-rich foods, with a focus on the role of anthocyanins in obesity control, diabetes control, cardiovascular disease prevention, and improvement of visual and brain functions, areas that have attracted much attention. Such health benefits are not necessarily derived from the antioxidant effect of anthocyanins, but in fact are produced by currently unestablished chemical properties beyond the antioxidant capacity of the molecules. However, a better understanding of the physiological functionality of anthocyanins remains to be elucidated. It is desirable, therefore, to clarify the molecular type and composition of the anthocyanins that confer specific health benefits and to conduct further investigation into the underlying molecular mechanisms. The pharmacological actions of anthocyanins could not be fully established without knowledge on the effects of treatment of anthocyanins alone, the effects of non-anthocyanin components, and the possible interactions between anthocyanin and non-anthocyanin species.

Purple corn anthocyanins retard diabetes-associated glomerulosclerosis in mesangial cells and db/db mice

PURPOSE

Diabetic glomerulosclerosis is the hardening of the renal glomeruli that can lead to kidney failure. In the early stage of glomerulosclerosis occur renal mesangial expansion and renal filtration dysfunction. Purple corn has been classified as a functional food and is rich in anthocyanins exerting potential disease-preventive activities. The in vitro study using human renal mesangial cells examined that anthocyanin-rich purple corn butanol fraction (PCB) can attenuate high glucose (HG)-promoted mesangial cell proliferation and matrix accumulation.

METHODS

Cells were cultured for 3 days in media containing 33 mM glucose in the presence of 1-20 μg/mL PCB. In the in vivo animal study, db/db mice were treated with 10 mg/kg anthocyanin-rich polyphenolic extracts of purple corn (PCE) for 8 weeks.

RESULTS

HG enhanced mesangial production of the fibrosis biomarkers of collagen IV and connective tissue growth factor (CTGF), which was markedly attenuated by adding PCB. Such mesangial fibrosis entailed interleukin-8 activation via eliciting Tyk2-STAT signaling pathway. PCB dampened HG-promoted mesangial hyperplasia that appeared to be attributed to increased expression of platelet-derived growth factor. The 8-week administration of PCE lowered plasma glucose level of db/db mice and ameliorated severe albuminuria. Moreover, PCE lessened collagen fiber accumulation in kidney glomeruli and CTGF expression via retarding TGF-β signaling. Protein expressions of nephrin and podocin, key proteins for filtration barrier function of the glomerular capillary wall, were repressed by treating mice with PCE.

CONCLUSION

Purple corn may be a potent therapeutic agent for the treatment for diabetes-associated glomerulosclerosis accompanying proteinuria and kidney filtration dysfunction.