Dietary flavanols

Schroeter H, Holt RR, Orozco TJ, Schmitz HH and Keen CL. 2003. Nutrition milk and absorption of dietary flavanols. Nature 426(6968) 787-788. 

Dietary Flavanols Biochemical Basis of Short-Term and Longer-Term Vascular Responses... 

Schewe T, Steffen Y, Sies H. 2008. How do dietary flavanols improve vascular function A position paper. Arch Biochem Biophys 476 102-106. 

Murphy, K.J., Chronopoulos, A.K., Singh, I., Francis, M.A., Moriarty, H., Pike, M.J., Turner, A.H., Mann, N.J., and Sinclair, A., Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function. Am. /. Clin. Nutr., 77, 1466-1473, 2003. 

Hollman PCH and Arts ICW. 2000. Flavonols, flavones and flavanols nature, occurrence and dietary burden. J SciFood Agric 80 1081-1093. 

The literature on vascular responses to dietary components [e.g., Fitzpatrick et al., 1995] has increased substantially in recent years. Short-term and long-term consumption of black tea was shown to reverse endothelial dysfunction in patients with coronary artery disease [Duffy et al., 2001]. On the acute shortterm time frame, which is taken here as the responses observed between 0 and 6 h, we demonstrated increases in flow-mediated dilation of the brachial artery upon intake of high-flavanol cocoa drink, but not of low-flavanol cocoa drink, in a crossover study [Heiss et al., 2003]. The effect of the flavanol-rich cocoa drink on flow-mediated dilation as well as the increase in circulating... 

Flavonoids represent one class of bioactive compounds that may have multiple beneficial effects on several chronic diseases [3-4]. Cocoa represents an example of a potentially rich dietary source of flavonoids. High concentrations of flavonoids are present in certain cocoas, predominately as the flavanol monomers (-)-epicatechin (epicatechin) and (+)-catechin (catechin), and as oligomers of these monomeric base units which are known as the procyanidins (Figure 1) [5]. Other potential rich dietary sources of flavonoids include tea, wine, grape juice, apples, onions and certain nuts. 

The flavonoids are a group of secondary metabolites widely distributed in the plant kingdom [63]. In 1984, more than 4000 flavonoids were identified in plants [64]. The major dietary sources of flavones are spices and pot herbs, such as parsley, rosemary, and thyme [65], whereas flavonols are predominantly found in onions, kale, broccoli, apples, berries and cherries, and in tea and red wine [66]. The flavanones are mainly restricted to citrus fruits [67], and flavanols are found in considerable amounts in tea, apricots, apples, and cherries [66]. 

TLC-MS Analysis of Carotenoids, Triterpenoids, and Flavanols in Plant Extracts and Dietary Supplements... 

It has been showed that chocolate is one of the most polyphenol-rich foods. According to Lee et al. [9], cocoa contains a higher content of flavonoids per serving than teas or red wine. Moreover cocoa powder is one of the richest dietary sources of flavanols (on a weight basis) identified so far, exceeded only by a few food ingredients such as buckwheat huUs, sorghum, cinnamon, and some superfruit [10]. Cocoa is also one of the richest dietary sources of polyphenols fisted in the Phenol-Explorer database [11] and one of the richest sources of procyanidins in the USDA Database for the Proanthocyanidin Content of Selected Foods [12] (Fig. 74.1). 

Flavonoids are also important antioxidants in many food sources. Flavonoids are divided into anthocyanins, flavanols/flavans, flavanones, flavones, flavonols, and isoflavones/isoflavonoids [15]. The sum of individual flavonoids (SIF) can be a simple indicator of flavonoid levels in dietary food sources which provides useful information for their potential benefits in human health. 

Recently, the biological impact of dietary polyphenols has been associated with the endothelial metabolism of NO. In particular, it has been shown that mono-O-methylated flavanols and other flavonoids by inhibition of endothelial NADPH oxidase suppress the formation of superoxide radical, that otherwise eliminates NO via diffusion-controlled formation of peroxynitrite (Steffen et al, 2008). Such a mechanism, preserving or enhancing the bioavailability of NO, may underlie the improvement of vascular endothelial function by certain flavonoid structures and its metabolites via, for instance, dilation of arterial vessels and lowering of blood pressure (Steffen et al, 2008). 

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