Vinson Joe A, Proch John, Bose Pratima, Muchler Sean, Taffera Pamela, Shuta Donna, Samman Najwa, Agbor Gabriel A
Department of Chemistry, Loyola Hall, University of Scranton, Scranton, PA 18510, USA.
J Agric Food Chem. 2006 Oct 18;54(21):8071-6. doi: 10.1021/jf062175j.
Chocolate today is often viewed as a food or snack with little nutritional value. The high saturated fat content of chocolate has also contributed to the belief that its consumption increases the risk of heart disease. However, recent human studies have proven that chocolate has beneficial effects on some pathogenic mechanisms of heart disease such as endothelial function and blood pressure. Although the antioxidant properties of chocolate have been known for some time, there has been no examination of its place in the U.S. diet as a source of antioxidants. This paper demonstrates that chocolate makes a significant contribution to U.S. per capita dietary antioxidants and by inference the European Community's. In the U.S. diet chocolate is the third highest daily per capita antioxidant source. An ex vivo study shows that epicatechin, a major polyphenol in chocolate and chocolate extracts, is a powerful inhibitor of plasma lipid oxidation due to polyphenols' ability to bind to lower density lipoproteins. Conversely, the fat from chocolate alone is a pro-oxidant in this model. This is also demonstrated in an in vivo human study. After consumption of dark chocolate and cocoa powder, the lower density lipoproteins isolated from plasma were protected from oxidation compared to the lipoproteins isolated after cocoa butter consumption, which were put under oxidative stress. In an animal model of atherosclerosis, cocoa powder at a human dose equivalent of two dark chocolate bars per day significantly inhibited atherosclerosis, lowered cholesterol, low-density lipoprotein, and triglycerides, raised high-density lipoprotein, and protected the lower density lipoproteins from oxidation. Chocolate has thus been shown to have potential beneficial effects with respect to heart disease.
如今，巧克力常被视为一种营养价值不高的食品或零食。巧克力中高饱和脂肪含量也使人认为食用巧克力会增加患心脏病的风险。然而，最近的人体研究证明，巧克力对心脏病的某些致病机制具有有益作用，如内皮功能和血压。尽管巧克力的抗氧化特性已为人所知一段时间，但尚未有人研究其在美国饮食中作为抗氧化剂来源的地位。本文表明，巧克力对美国人均膳食抗氧化剂有重大贡献，由此推断对欧共体也是如此。在美国饮食中，巧克力是人均每日抗氧化剂的第三大来源。一项体外研究表明，表儿茶素是巧克力和巧克力提取物中的一种主要多酚，由于多酚能够与低密度脂蛋白结合，它是血浆脂质氧化的强力抑制剂。相反，在该模型中，仅巧克力中的脂肪是一种促氧化剂。这一点在一项人体体内研究中也得到了证实。食用黑巧克力和可可粉后，从血浆中分离出的低密度脂蛋白受到保护，免受氧化，而食用可可脂后分离出的脂蛋白则处于氧化应激状态。在动脉粥样硬化动物模型中，以相当于每天两根黑巧克力棒的人体剂量的可可粉可显著抑制动脉粥样硬化，降低胆固醇、低密度脂蛋白和甘油三酯，提高高密度脂蛋白，并保护低密度脂蛋白免受氧化。因此，巧克力已被证明对心脏病具有潜在的有益作用。
