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Cacao polyphenols
 

Cacao polyphenols

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Health benefits of cacao polyphenols.

Health benefits of cacao polyphenols.

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  • Figure 2. The fruit of the theobroma cocoa tree.
  • Figure 1. Health-relevant effect of epicatechins.
  • Figure 3. Endothelium-dependent effect of cocoa polyphenols. NO is released from endothelial cells mainly in response to shear stress elicited by the circulating blood or receptor-operated substances such as acetylcholine, bradykinin, or serotonin. NO is synthesized by eNOS from l-arginine in the presence of the cofactor thetrahydrobiopterin. The activation may be due to an increase in Ca2+ or a phosphorylation of eNOS by the PI3-kinase/Akt pathway. Cocoa also lowers vascular arginase activity in human endothelial cell in vitro, thus augmenting the local levels of l-arginine. Once released, NO increases intracellular cGMP concentrations and, in turn, induces a relaxation of vascular smooth muscle cells. NO not only leads to vasodilation but also prevents leukocyte adhesion and migration, smooth muscle cell proliferation, and platelet adhesion and aggregation. Other NO-mediated mechanisms are discussed. Antioxidant effects may reduce the production of reactive oxidant species, thus contributing to an enhanced endothelial function. Cocoa polyphenols may activate endothelium-derived hyperpolarizing factor (EDHF), increase endothelial prostacyclin release, or inhibit the synthesis of endothelin-1 (ET). Moreover, polyphenols may directly inhibit angiotensin-converting enzyme (ACE). AII indicates angiotensin II; AI, angiotensin I; PKC, protein kinase C; SOD, superoxide dismutase; PGI2, prostacyclin; ACE, angiotensin-converting enzyme; ECE, endothelin-converting enzyme; AT1, angiotensin receptor; ET-1, endothelin 1; bET-1, big endothelin 1; ETa/b, endothelin receptor a and b; cGMP, cyclic guanosine monophosphate; and ROS, reactive oxygen species.

Cacao polyphenols Cacao polyphenols Presentation Transcript

  • Publication # 2Pennington Biomedical Research Center Division of Education Phillip Brantley, PhD, Director Pennington Biomedical Research CenterSteven Heymsfield, MD, Executive Director PBRC 2012
  • Overview…  An increasing body of epidemiologic evidence supports the concept that diets rich in fruits and vegetables promote health and attenuate, or delay, the onset of various diseases, including cardiovascular disease, cancer, and certain neurodegenerative disorders. Epidemiologic data has linked these health benefits, at least in part, to the presence of certain flavonoids in fruits and vegetables. PBRC 2012
  • Flavonoids…  Flavonoids are a group of polyphenolic compounds that occur widely in fruits, vegetables, tea, red wine, and chocolate. Cocoa and chocolate products have the highest concentration of flavonoids among commonly consumed foods. Over 10 percent of the weight of cocoa powder is flavonoids. PBRC 2012
  •  Cocoa and chocolate products have been delicacies for hundreds of years. Cocoa and chocolate have only recently have they been recognized as significant sources of phytochemicals, with healthful effects. Cocoa and chocolate are among the most concentrated sources of the procyanidin flavonoids, catechin, and epicatechin. PBRC 2012
  • The fruit of the Theobroma cacao tree Corti R et al. Circulation 2009;119:1433-1441 PBRC 2012
  • Chocolate Consumption  Americans eat a lot of chocolate in the form of candy (about 5.5 kg/year per person or 12 pounds), but not as much as people in some northern European countries. In Germany, the country with the highest chocolate consumption, it is estimated at 11.4 kg/year (25 pounds) for each person. Each candy bar contains about 210 calories, 13 g fat (7 of which is saturated), 23 g of carbohydrate, and 3 g of protein. PBRC 2012
  • Flavonoids in Chocolate   principally The flavonoids in cocoa/chocolate, catechin and epicatechin, exist in long molecules.  In most foods, catechins are fairly short molecules, maybe two, three linked together, but in chocolate and cocoa they are much longer.  These structural characteristics of catechin and epicatechin represent the molecular basis for both their hydrogen-donating (radical-scavenging) properties and their metal-chelating antioxidant properties. PBRC 2012
  • Flavonoids in Chocolate  in 60% loss of total flavonoids. Processing of cocoa results  Among flavanols, epicatechin has the largest decline (67%).  In terms of flavonols, quercetin declines the most (86%). Most cocoas undergo fermentation steps which subject flavonoids in the cocoa to heat and acidic conditions. High processing temperatures, alkali treatment and longer processing time all reduce the amount of cocoa polyphenols. C.L. Hii et al. As. J. Food Ag-Ind. 2009, 2(04), 702-722 PBRC 2012
  • Flavonoid Content: Variable  food or beverage product The actual recipe for the finished determines the amount of a given cocoa (and flavonoid) added. Other ingredients can influence the final product such as the type of fat used, type of milk and milk products used and the addition of sugar and salt. PBRC 2012
  • Flavonoid Content  varying antioxidant content. Different types of chocolate contain In finished products, the amount of cocoa ranges from 7% to 35% in milk chocolate and 30% to 80% in dark chocolate. Consequently, there is a lot of variability and is generally twice as high in dark than in milk chocolate. Also interesting is the fact that white chocolate does not contain polyphenols. PBRC 2012
  • Recent Studies at the total polyphenols in Several studies have looked foods and beverages in the American diet, and chocolate and cocoa have one of the highest levels of antioxidants consistently. Cocoa and chocolate have higher levels of polyphenols than in many fruits. It is 20 times higher than in tomatoes, 2 times higher than in garlic, and over 3 times higher than in grapes. PBRC 2012
  • Catechin/Epicathecinconcentrations in foods  Flavanol Content, mg/kg or Source mg/L Chocolate 460–610 Beans 350–550 Green tea 100–800 Apricots 100–250 Red wine 80–300 Black tea 60–500 Cherries 50–220 Peaches 50–140 Blackberries 130 Apples 20–120 Cider 40 PBRC 2012 Circulation March 17, 2009 vol. 119 no. 101433-1441
  • Numerous dietary intervention studies in humans and animals indicate that flavanol-rich foods and beverages might exert cardioprotective effects with respect to vascular function and platelet reactivity. There is an improvement in blood vessel wall function, reduction in platelets, and improvement in blood pressure, insulin resistance and blood lipids. Circulation . 2009; 119: 1433-1441 PBRC 2012
  • Antioxidant Capacity PBRC 2012
  • Atherogenesis…  Phenolic antioxidants have been shown to inhibit the oxidation of low- density lipoprotein (LDL) cholesterol, and mounting evidence suggests that it is the oxidized form of LDL that leads to the buildup of fatty plaques in arteries. PBRC 2012
  • Atherogenesis… have also shown to Extracts of cocoa powder significantly inhibit LDL oxidation. Studies have found that cocoa preserves the lipids in the lipid droplets in the circulatory system and it is concentration-dependent. Higher amount of cocoa polyphenols preserves greater amount of lipid droplets. Cocoa phenols has shown to inhibit LDL oxidation by 75%, whereas red wines only inhibit LDL oxidation by 37-65%. PBRC 2012
  • Health-relevant effect of epicatechins  Corti R et al. Circulation 2009;119:1433-1441 PBRC 2012
  • Endothelium-dependent effect of cocoa polyphenols  Corti R et al. Circulation 2009;119:1433-1441 PBRC 2012
  •  Interestingly, cocoa powder and cocoa extracts have been shown to exhibit greater antioxidant capacity than many other flavanol- rich foods and food extracts, such as green and black tea, red wine, blueberry, garlic, and strawberries. However, no long-term studies have evaluated the effects of cocoa polyphenol compounds on the oxidative modification of LDL in humans. PBRC 2012
  • Short-term human studies… and catechin were measured The levels of epicatechin in humans at zero, one, two, and six hours following consumption of a single meal of chocolate. The concentration in plasma levels peaked at about one hour; however, by six hours the concentrations had almost disappeared from the plasma. Indicated that cocoa flavonoids are absorbed and cleared from circulation relatively quickly. PBRC 2012
  • Short-term human studies…  Support the recommendations to consume several servings of fruit and vegetables per day as seen in a number of clinical trials with chocolate and other flavonoid-rich foods. at mor e fruit E Spacing intake of flavonoid-rich foods throughout the day could help to provide a continuous supply. AM: PM: Berries Grapes PBRC 2012
  • More studies… seven times more Because there is six to epicatechin than catechin in cocoa/chocolate, most attention has focused on epicatechin in scientific studies. Consistent with early studies, human studies indicate that small doses of epicatechin are effective. There is a statistically significant increase in plasma antioxidant capacity and reduction in lipid peroxides following cocoa/chocolate consumption. PBRC 2012
  • Benefits…  Epicatechin and other flavonoids not only have a direct antioxidant effect, but they may also have a sparing effect on other antioxidants such as Vitamins C and E. PBRC 2012
  • Other Mechanisms… Although flavanol-rich cocoa and chocolate have the potential to improve an individual’s antioxidant defense system, there are other cellular mechanisms through which these flavanol-rich foods can affect cardiovascular health: Inflammation Platelet aggregation Nitric oxide (NO)-mediated endothelial changes PBRC 2012
  • Inflammation PBRC 2012
  •  Atherosclerosis and heart failure, as well as risk factors such as hypertension and hypercholesterolemia, can activate several proinflammatory enzyme systems. Once activated, these enzymes produce reactive oxygen species and other radicals that can modify nitric oxide availability and LDL and contribute to blood vessel dysfunction. PBRC 2012
  •  Flavanol-rich cocoa liquor has been shown to stimulate nitric oxide production and to significantly reduce the activities of enzymes involved in oxidative stress. In addition, cocoa flavanols and procyanidins may modulate other mediators of inflammation. PBRC 2012
  • Platelets PBRC 2012
  •  In addition to its influence on oxidative defense mechanisms, polyphenols seem to benefit cardiovascular health in other ways- through regulation of platelet reactivity. Given the prominent role of platelets in the development and manifestation of acute myocardial infarction, stroke, and venous thromboembolism, antiplatelet strategies are an important consideration. A modest decrease in platelet reactivity can be of value because it reduces the probability of clotting. PBRC 2012
  •  In one study to determine whether cocoa inhibits platelet activation and function, subjects were given either water or 300 ml of cocoa that provided a very high amount of polyphenols. During the six hour time period following intake of cocoa, there was a reduction in adhesion molecules on the surface of the platelets, making the platelets less likely to adhere to other molecules in the bloodstream. This is the same response that would be seen following intake of antiplatelet agents such as aspirin. PBRC 2012
  • Endothelium PBRC 2012
  •   disrupt blood vessel function such There are many things that can as stress, ischemia, inflammation, and disease states such as atherosclerosis, diabetes mellitus, and hypertension. Any of the above can influence the vascular tone and cause an overall shift toward the prothrombotic state. According to research, it is possible that flavanols, by functioning as antioxidants, can improve endothelial function through the prevention and possible reduction of oxidative damage. About 150 mg of flavonoids is needed to modulate anti- inflammatory prostacylin and pro-inflammatory leukotriene concentrations. PBRC 2012
  • Conclusions…  Several large scale studies have shown that regular dietary intake of plant-derived foods and beverages reduces the risk of coronary heart disease and stroke and is inversely associated with the risk of cardiovascular disease. Plants have many phytochemicals including flavonoids. Consumption of flavanol-rich foods such as white, green, and black tea, grapes, wine, apple juice, cocoa, lentils, and black- eyed peas is associated with the reduced risk for cardio vascular disease. PBRC 2012
  • References Roberto Corti, Andreas J. Flammer, Norman K. Hollenberg and Thomas F. Lüscher. Cocoa and Cardiovascular Health. Circulation 2009;119:1433-1441. C.L. Hii, C.L. Law, S. Suzannah, Misnawi, and M. Cloke. Polyphenols in cocoa (Theobroma cacao L.) As. J. Food Ag-Ind. 2009, 2(04), 702-722 . Keen C, et al. Dietary polyphenols and health: Proceedings of the 1st international conference on polyphenols and health. Amer J Clin Nutr. 2005. 81:1 298S-303S. Available at: http://www.ajcn.org/cgi/content/full/81/1/298S PBRC 2012
  • References Keen C. Chocolate: Food as medicine/medicine as food. J Amer Coll of Nutr. 2001. 20:90005 436S-439S. Available at: http://www.jacn.org/cgi/content/full/20/suppl_5/436S Wan Y, et al. Effects of cocoa powder and dark chocolate on LDL oxidative susceptibility and prostaglandin concentrations in humans. Amer J Clin Nutr. 2001. 74:5 596-602. http://pubs.acs.org/hotartcl/tcaw/99/jul/chocolate.html http://sciweb.nybg.org/science2/pdfs/mb/chocolate.pdf#search= alternative%20therapies%20sept/oct%20chocolate‘ PBRC 2012
  • Pennington Biomedical Research Center VISION  Our vision is to lead the world in eliminating chronic diseases.  MISSION Our mission is to discover the triggers of chronic diseases through innovative research that improves human health across the lifespan.  We are helping people live Well Beyond the Expected. The Pennington Center has several research areas, including: Clinical Obesity Research Experimental Obesity Functional Foods Health and Performance Enhancement Nutrition and Chronic Diseases Nutrition and the Brain Dementia, Alzheimer’s and healthy aging Diet, exercise, weight loss and weight loss maintenance The research fostered in these areas can have a profound impact on healthy living and on the prevention of common chronic diseases, such as heart disease, cancer, diabetes, hypertension and osteoporosis.  The Division of Education provides education and information to the scientific community and the public about research findings, training programs and research areas, and coordinates educational events for the public on various health issues.  We invite people of all ages and backgrounds to participate in the exciting research studies being conducted at the Pennington Center in Baton Rouge, Louisiana. If you would like to take part, visit the clinical trials web page at www.pbrc.edu or call (225) 763-3000. PBRC 2012