The most important studies on the properties of cocoa, phytochemical composition, intakes, allergies, etc.

Massaro M, Scoditti E, Carluccio MA, Kaltsatou A, Cicchella A. Effect of Cocoa Products and Its Polyphenolic Constituents on Exercise Performance and Exercise-Induced Muscle Damage and Inflammation: A Review of Clinical Trials. Nutrients. 2019 Jun 28;11(7):1471. doi: 10.3390/nu11071471.

Abstract. In recent years, the consumption of chocolate and, in particular, dark chocolate has been "rehabilitated" due to its high content of cocoa antioxidant polyphenols. Although it is recognized that regular exercise improves energy metabolism and muscle performance, excessive or unaccustomed exercise may induce cell damage and impair muscle function by triggering oxidative stress and tissue inflammation. The aim of this review was to revise the available data from literature on the effects of cocoa polyphenols on exercise-associated tissue damage and impairment of exercise performance. To this aim, PubMed and Web of Science databases were searched with the following keywords: "intervention studies", "cocoa polyphenols", "exercise training", "inflammation", "oxidative stress", and "exercise performance". We selected thirteen randomized clinical trials on cocoa ingestion that involved a total of 200 well-trained athletes. The retrieved data indicate that acute, sub-chronic, and chronic cocoa polyphenol intake may reduce exercise-induced oxidative stress but not inflammation, while mixed results are observed in terms of exercise performance and recovery. The interpretation of available results on the anti-oxidative and anti-inflammatory activities of cocoa polyphenols remains questionable, likely due to the variety of physiological networks involved. Further experimental studies are mandatory to clarify the role of cocoa polyphenol supplementation in exercise-mediated inflammation.

Gröne M, Sansone R, Höffken P, Horn P, Rodriguez-Mateos A, Schroeter H, Kelm M, Heiss C. Cocoa Flavanols Improve Endothelial Functional Integrity in Healthy Young and Elderly Subjects. J Agric Food Chem. 2020 Feb 19;68(7):1871-1876. doi: 10.1021/acs.jafc.9b02251.

Abstract. Cocoa flavanols (CFs) can improve flow-mediated dilation (FMD), blood pressure, and vascular stiffness in healthy subjects. Endothelial microparticles (EMPs) are markers of endothelial functional integrity, reflecting activation and injury. In plasma samples, we investigated whether age-dependent changes in circulating EMPs exist and whether CFs decrease EMPs in healthy humans. The concentrations of CD31+/41-, CD144+, and CD62e+ EMPs (flow cytometry) were increased in healthy elderly (n = 19) compared to young (n = 20) non-smokers. EMPs correlated with age, systolic blood pressure, and pulse wave velocity. CD31+/41- and CD62e+ EMPs inversely correlated with FMD. Following 2 weeks twice-daily CF consumption (450 mg), CD31+/41- and CD144+ EMPs decreased in both young and elderly subjects compared to the CF-free control. The EMP decrease inversely correlated with FMD improvements. Cardiovascular aging is associated with increased EMPs that can be modulated by dietary flavanols along with improvements in vascular function. This indicates that flavanol consumption can improve endothelial functional integrity in healthy humans.

Yoo, H., & Kim, H. S. (2019). Different Extraction Solvents and Sample Preparation Methods Affect the Antioxidant Activities and Total Phenol Contents of Theobroma Cacao Powder (P01-016-19). Current Developments in Nutrition, 3(Supplement_1), nzz028-P01.

Abstract. Objectives Cacao(Theobroma cacao) has been widely consumed since more than 4000 years ago which was regarded as sacred food. Cacao has been considered as a strong antioxidant due to its abundant phenolic and especially flavonoid contents. In this experiment, different extraction solvents and methods were used to analyze whether these factors affect the antioxidant activities and phytochemical compounds of cacao powder extracts. Methods Four different cacao extract samples were examined to identify their anti-oxidative activities; raw cacao powder extracted in 70% methanol solution(RM), raw cacao powder extracted in 80% ethanol solution(RE), freeze dried cacao powder extracted in 70% methanol solution(FM), freeze dried cacao powder extracted in 80% ethanol solution(FE). Total phenolic compound content was calculated based on gallic acid standard curve and total flavonoid content was calculated based on the standard curve of quercetin. ABTS scavenging activity was experimented with ABTS reagent diluted by PBS(pH7.4) to make the O.D. value 0.7 ± 0.02 at 734 nm before using 2.5 mM ABTS. The DPPH radical scavenging activity was assessed by 1 mM DPPH methanol solution. Results The contents of total phenol compounds were 45.4 mg GAE/g(RM), 37.3 mg GAE/g(RE), 50.6 mg GAE/g(FM), and 52.7 mg GAE/g(FE). The contents of total flavonoid compounds were 34.3 mg QE/g(RM), 29.7 mg QE/g(RE), 85.1 mg QE/g(FM), and 89.7 mg QE/g(FE). FM group showed the highest ABTS radical scavenging activity which is a marker of antioxidant activity but the other sample groups represented almost as high ABTS radical scavenging activity as FM group. RM group showed the highest DPPH radical scavenging activity which is also a marker of antioxidant activity. Conclusions The results show that different extract solvents and sample preparation methods affect DPPH radical scavenging activity, total phenol and flavonoid contents of cacao powder extracts. Therefore, appropriate methods should be applied according to the purpose of the study.

Rossin D, Barbosa-Pereira L, Iaia N, Testa G, Sottero B, Poli G, Zeppa G, Biasi F. A Dietary Mixture of Oxysterols Induces In Vitro Intestinal Inflammation through TLR2/4 Activation: The Protective Effect of Cocoa Bean Shells. Antioxidants (Basel). 2019 May 31;8(6):151. doi: 10.3390/antiox8060151.

Abstract. Background: Exaggerated Toll-like receptor (TLR)-mediated immune and inflammatory responses play a role in inflammatory bowel diseases. This report deals with the ability of a mixture of oxysterols widely present in cholesterol-rich foods to induce in vitro intestinal inflammation through TLR up-regulation. The anti-inflammatory action of four cocoa bean shell (CBS) extracts with different polyphenol content, was tested. Methods: Differentiated intestinal CaCo-2 cells were treated with a dietary oxysterol mixture (Oxy-mix) (60 µM). The expression and activation of TLR2 and TLR4, as well as the production of their downstream signaling effectors IL-8, IFNβ and TNFα were analyzed in the presence or absence of TLR antibodies. Honduras CBS extracts were characterized for their polyphenol contents; their anti-inflammatory action was analyzed in CaCo-2 cells treated with Oxy-mix. Results: Oxysterol-dependent TLR-2 and TLR4 over-expression and activation together with cytokine induction were abolished by blocking TLRs with specific antibodies. Polyphenol-rich CBS extracts consisting of high quantities of (-)-epicatechin and tannins also prevented TLR induction. Conclusions: TLR2 and TLR4 mainly contribute to inducing oxysterol-dependent intestinal inflammation. The fractionation method of CBS allowed the recovery of fractions rich in (-)-epicatechin and tannins able to counteract oxysterol-induced inflammation, thus highlighting the beneficial biological potential of specific CBS extracts.

Bhagat AR, Delgado AM, Issaoui M, Chammem N, Fiorino M, Pellerito A, Natalello S. Review of the Role of Fluid Dairy in Delivery of Polyphenolic Compounds in the Diet: Chocolate Milk, Coffee Beverages, Matcha Green Tea, and Beyond. J AOAC Int. 2019 Sep 1;102(5):1365-1372. doi: 10.5740/jaoacint.19-0129. 

Abstract. Dairy-based functional beverages have been a growing segment as consumer demands for health foods have shifted focus from simply enhancing lifespan to protecting health. Green tea is often limited in use because of poor bioavailability and disagreeable taste. However, milk is considered an ideal platform for the delivery of active polyphenolic compounds in green tea. Furthermore, the antioxidant enzymatic activity and antioxidant index of polyphenols in green tea have been known to be protected through interaction with dairy proteins inside the unstable intestinal environment. In addition, consumption of green tea infused with milk has been found to have a significant impact on reducing skin wrinkles and roughness in elderly subjects, through a decrease in lipid peroxidation and a concomitant reduction in oxidative stress. A similar affinity has been observed between antioxidants in coffee and milk proteins. Dark chocolate has been known to contain significant phenolic content and antioxidant activity. The activation of protein complex NF-κB, which is responsible for cell survival, was found to be significantly reduced upon consumption of cocoa with water, whereas consuming cocoa with milk had no effect on the bioavailability of the phenolic compounds in cocoa. The popularity of dairy as the source for polyphenol fortified beverages in the diet will be dictated by optimization of the technology for maximizing the bioavailability of the antioxidants.

Garcia JP, Santana A, Baruqui DL, Suraci N. The Cardiovascular effects of chocolate. Rev Cardiovasc Med. 2018 Dec 30;19(4):123-127. doi: 10.31083/j.rcm.2018.04.3187. 

Abstract. The antioxidants as polyphenols, especially flavanols present in cocoa, exert a favorable effect on endothelium vasodilation, modulate inflammatory markers, and decrease platelet aggregation, lipid oxidation and insulin resistance. Recent nutritional intervention trials and molecular studies demonstrate that consumption of cocoa, particularly rich in flavanols, is beneficial to promote cardiovascular health. This review describes the cardiovascular effects of chocolate.

Lopes JP, Kattan J, Doppelt A, Nowak-Węgrzyn A, Bunyavanich S. Not so sweet: True chocolate and cocoa allergy. J Allergy Clin Immunol Pract. 2019 Nov-Dec;7(8):2868-2871. doi: 10.1016/j.jaip.2019.04.023.

Abstract. Food allergy to chocolate and cocoa is considered possible, but there has been no report to date of challenge-proven, IgE-mediated allergy to chocolate or cocoa. Although population studies cite a prevalence of self-reported chocolate/cocoa allergy of 0.5 to 0.7% in select populations,1 self-reported food allergy is notoriously inaccurate, and objective testing was not used to corroborate chocolate or cocoa allergy status in these studies. 1 The majority of empirically defined chocolate and cocoa allergies are thought to be due to cross-contamination from common allergens, including peanut,2 tree nuts, or milk.3, 4 Here we report for the first time a case series of oral food challenge-confirmed, IgE-mediated chocolate/cocoa allergy.

Zięba K, Makarewicz-Wujec M, Kozłowska-Wojciechowska M. Cardioprotective Mechanisms of Cocoa. J Am Coll Nutr. 2019 Aug;38(6):564-575. doi: 10.1080/07315724.2018.1557087.

Abstract. Cardiovascular diseases are the main cause of deaths in highly developed countries. Dietetic interventions that involve recommendations for consumption of products with a confirmed health-improving action are an important aspect of prevention of cardiovascular diseases. Cocoa is an alimentary product with significant cardioprotective potential due to its high content of bioactive compounds. The aim of the present study was to review the most recent literature concerning the effectiveness and mechanisms of action of compounds contained in cocoa with regard to selected cardiovascular risk factors and cardiometabolic markers. Study results indicate that cocoa consumption, especially in the form of dark chocolate with high flavonoid content, may be a good strategy to diminish cardiovascular risk due to its beneficial effect on platelet aggregation, decreasing blood pressure, diminishing dyslipidemia, and decreasing blood plasma glucose concentration. Many studies have shown that cocoa-derived flavonoids have antioxidant and anti-inflammatory activity and also play a significant role in preventing insulin resistance. However, in order to completely confirm the potential cardiovascular benefits, it is necessary to conduct larger and longer studies, also with regard to potential dangers associated with long-term consumption of large amounts of flavonoids and determination of a safe and effective dose. Key teaching points Cocoa consumption may be a good strategy in diminishing cardiovascular risk. Beneficial effects on platelet aggregation, blood pressure, dyslipidemia, glycemia, as well as antioxidant and anti-inflammatory activity are observed. There is a need to conduct larger and longer studies to determine a safe and effective dose of cocoa flavonoids.

Cavarretta E, Peruzzi M, Del Vescovo R, Di Pilla F, Gobbi G, Serdoz A, Ferrara R, Schirone L, Sciarretta S, Nocella C, De Falco E, Schiavon S, Biondi-Zoccai G, Frati G, Carnevale R. Dark Chocolate Intake Positively Modulates Redox Status and Markers of Muscular Damage in Elite Football Athletes: A Randomized Controlled Study. Oxid Med Cell Longev. 2018 Nov 21;2018:4061901. doi: 10.1155/2018/4061901. 

 Abstract. Intensive physical exercise may cause increase oxidative stress and muscular injury in elite football athletes. The aim of this study was to exploit the effect of cocoa polyphenols on oxidative stress and muscular injuries induced by intensive physical exercise in elite football players. Oxidant/antioxidant status and markers of muscle damage were evaluated in 24 elite football players and 15 controls. Furthermore, the 24 elite football players were randomly assigned to either a dark chocolate (>85% cocoa) intake (n = 12) or a control group (n = 12) for 30 days in a randomized controlled trial. Oxidative stress, antioxidant status, and muscle damage were assessed at baseline and after 30 days of chocolate intake. Compared to controls, elite football players showed lower antioxidant power and higher oxidative stress paralleled by an increase in muscle damage markers. After 30 days of dark chocolate intake, an increased antioxidant power was found in elite athletes assuming dark chocolate. Moreover, a significant reduction in muscle damage markers (CK and LDH, p < 0.001) was observed. In the control group, no changes were observed with the exception of an increase of sNox2-dp, H2O2, and myoglobin. A simple linear regression analysis showed that sNox2-dp was associated with a significant increase in muscle damage biomarker release (p = 0.001). An in vitro study also confirmed that polyphenol extracts significantly decreased oxidative stress in murine myoblast cell line C2C12-derived. These results indicate that polyphenol-rich nutrient supplementation by means of dark chocolate positively modulates redox status and reduced exercise-induced muscular injury biomarkers in elite football athletes. This trial is registered with NCT03288623.