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Unformatted text preview: ABSTRACT Background: Flavonoids are polyphenolic compounds of plant origin with antioxidant effects. Flavonoids inhibit LDL oxidation and reduce thrombotic tendency in vitro. Little is known about how cocoa powder and dark chocolate, rich sources of polyphe- nols, affect these cardiovascular disease risk factors. Objective: We evaluated the effects of a diet high in cocoa pow- der and dark chocolate (CP-DC diet) on LDL oxidative suscepti- bility, serum total antioxidant capacity, and urinary prostaglandin concentrations. Design: We conducted a randomized, 2-period, crossover study in 23 healthy subjects fed 2 diets: an average American diet (AAD) controlled for fiber, caffeine, and theobromine and an AAD supplemented with 22 g cocoa powder and 16 g dark choco- late (CP-DC diet), providing < 466 mg procyanidins/d. Results: LDL oxidation lag time was < 8% greater ( P = 0.01) after the CP-DC diet than after the AAD. Serum total antioxidant capacity measured by oxygen radical absorbance capacity was < 4% greater ( P = 0.04) after the CP-DC diet than after the AAD and was positively correlated with LDL oxidation lag time ( r = 0.32, P = 0.03). HDL cholesterol was 4% greater after the CP-DC diet ( P = 0.02) than after the AAD; however, LDL-HDL ratios were not significantly different. Twenty-four–hour urinary excretion of thromboxane B 2 and 6-keto-prostaglandin F 1 a and the ratio of the 2 compounds were not significantly different between the 2 diets. Conclusion: Cocoa powder and dark chocolate may favorably affect cardiovascular disease risk status by modestly reducing LDL oxidation susceptibility, increasing serum total antioxidant capacity and HDL-cholesterol concentrations, and not adversely affecting prostaglandins. Am J Clin Nutr 2001;74:596–602. KEY WORDS Cocoa powder, dark chocolate, LDL oxidation, oxygen radical absorbance capacity, prostaglandins, flavonoids, procyanidins, polyphenols, catechins INTRODUCTION Flavonoids are a group of polyphenolic compounds that occur widely in fruit, vegetables, tea, and red wine. Certain cocoas and chocolates can also be rich sources of flavonoids, especially the sub- class of oligomeric flavonoids known as procyanidins (1–4). Indeed, the antioxidant activity of cocoa and chocolate was shown to be cor- related with its catechin and procyanidin contents. Arts et al (2) reported that dark chocolate contains catechins (a group of flavan-3-ol flavonoid compounds) at an average concentration of 0.535 mg/g, 4 times that of tea (139 mg/L). In a representative sample of the Dutch population, chocolate contributed 20% of the catechin intake whereas tea contributed 55%. In younger age groups, in which choco- late is probably preferred to tea, and in countries where tea is con- sumed less, chocolate may be a more important source of catechins and their oligomers (eg, procyanidins). Therefore, cocoa and choco- late can be important dietary sources of flavonoids in addition to tea....
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This note was uploaded on 01/06/2012 for the course BIOL 1322 taught by Professor Aliciabrown during the Summer '11 term at Collins.
- Summer '11