Polyphenols consumption

Mennen, L.I., Walker, R., Bennetau-Pelissero, C., and Scalbert, A., Risks and safety of polyphenol consumption, Am. J. Clin. Nutr., 81, 326S, 2005. 

Polyphenol consumption as flavonoids has been shown to decrease the risk of heart disease in a cross-cultural epidemiological study. Most recently, an epidemiological study found that Harvard male graduates who ate a moderate amount of chocolate and other candy had a 36% lower risk of death compared with non-candy eaters. The authors speculate that it is the antioxidants present in the chocolate that provide a health benefit. 

FIGURE 12.2 Possible routes after polyphenol consumption. Modified from Scalbert and Williamson (2000). ... 

Earlier estimates of polyphenols consumption in the United States fixed at 1 g/day the intake of flavonoids, of which 115 mg/day were flavonols, flavones, and flava-nones." However, more recent data establish this intake in much lower amounts of these flavonoids ranging from 15 to 23 mg/day, plus 12 mg of anthocyanins and up to 70 mg of procyanidins per day in the United States (Table 3.4). Similarly, flavonols and flavone intake in other European countries and Japan show figures much lower that those initially estimated by Khiinau," as can be seen in Table 3.4." To these values, should be added the intake of flavonoids from nutraceuticals and functional foods enriched in these polyphenols, consumption of which has increased considerably in recent years. Therefore, it would be necessary to develop reliable databases of polyphenols/flavonoids in foods and nutraceuticals to obtain more updated estimates of flavonoids intakes. 

In the last few decades, several epidemiological studies have shown that a dietary intake of foods rich in natural antioxidants correlates with reduced risk of coronary heart disease particularly, a negative association between consumption of polyphenol-rich foods and cardiovascular diseases has been demonstrated. This association has been partially explained on the basis of the fact that polyphenols interrupt lipid peroxidation induced by reactive oxygen species (ROS). A large body of studies has shown that oxidative modification of the low-density fraction of lipoprotein (LDL) is implicated... 

Dietary consumption of polyphenols is associated with a lower risk of degenerative diseases. In particular, protection of serum lipids from oxidation, which is a major step in the development of arteriosclerosis, has been demonstrated. More recently, new avenues have been explored in the capacity of polyphenols to interact with the expression of the human genetic potential. The understanding of the interaction between this heterogeneous class of compounds and cellular responses, due either to their ability to interplay in the cellular antioxidant network or directly to affect gene expression, has increased. 

NIGDIKAR s v, WILLIAMS N R, GRIFFIN B A, HOWARD A N (1998) Consumption of red wine polyphenols reduces the susceptibility of low-density lipoproteins to oxidation in y No, American Journal of Clinical Nutrition, 68, 258-65. 

DeGraft-Johnson J, Kolodziejczyk K, Krol M, Nowak P, Krol B and Nowak D. 2007. Ferric-reducing ability power of selected plant polyphenols and their metabolites implications for clinical studies on the antioxidant effects of fruits and vegetable consumption. Basic Clin Pharmacol Toxicol 100(5) 345-352. 

There is a more interesting, and possibly more important, explanation. A principal difference between American and French diets is the consumption of wine, specifically red wine. Could there be something in wine that accounts for the French Paradox Attention has been focused on a class of compounds found in red wine called polyphenols (they are found in white wine as well but in much smaller amounts). These have potent antioxidant properties. Most of the attention has been focused on resveratrol ... 

As its name suggests, supercritical fluid extraction (SEE) relies on the solubilizing properties of supercritical fluids. The lower viscosities and higher diffusion rates of supercritical fluids, when compared with those of liquids, make them ideal for the extraction of diffusion-controlled matrices, such as plant tissues. Advantages of the method are lower solvent consumption, controllable selectivity, and less thermal or chemical degradation than methods such as Soxhlet extraction. Numerous applications in the extraction of natural products have been reported, with supercritical carbon dioxide being the most widely used extraction solvent. However, to allow for the extraction of polar compounds such as flavonoids, polar solvents (like methanol) have to be added as modifiers. There is consequently a substantial reduction in selectivity. This explains why there are relatively few applications to polyphenols in the literature. Even with pressures of up to 689 bar and 20% modifier (usually methanol) in the extraction fluid, yields of polyphenolic compounds remain low, as shown for marigold Calendula officinalis, Asteraceae) and chamomile Matricaria recutita, Asteraceae). " ... 

Salmon, J. M., Fornairon-Bonnefond, C., and Mazauric, J. P. (2002). Interactions between wine lees and polyphenols Influence on oxygen consumption capacity during simulation of wine aging. J. Food Sci. 67,1604-1609. 

The clinical relevance of data obtained from studies with single compounds is questionable, because most studies were performed in in vitro systems, limiting the predictability of the effects of the examined compounds in vivo. Moreover, some polyphenolics, such as quercetin, were shown to interact with the absorption or metabolism of drugs only at very high concentrations (50-100 pmol/L), which are likely to exceed the expected in vivo concentration after the consumption of a moderate amount of a grapefruit/ citrus product. Also, flavonoids have been demonstrated to potentially induce apoptosis in cell lines at concentrations comparable to those used for some in vitro drug interaction studies (64-66). This potentially could have impaired the investigation of enzyme and transporter activities. 

Some polyphenols inhibit platelet aggregation reducing the risk of thrombosis [171-173]. This effect may be due to a series of interaction of flavonoids in different biochemical pathways, such as by inhibition of cyclooxygenase and lipoxygenase, that are involved in the arachidonic acid metabolism in the platelets, or by inhibition of the formation of tromboxane and of the receptor function of the same [173-176]. Regular consumption of wine, tea and chocolate has been associated to the reduction of platelet aggregation, cardio-vascular diseases and thrombosis [171,177-179]. 

A modest but not significant inverse correlation between the intake of flavonols and flavones and subsequent mortality rates was found in a prospective cohort study of US Health Professionals by Rimm et al [206]. The authors do not exclude that flavonoids have a protective effect in men with established coronary heart disease although strong evidence was missing. Also other studies failed to demonstrate a significant statistical association between the intake of polyphenols and CHD. In Great Britain for instance coronary and total mortality even rose with the intake of the major flavonol source, tea [207], The most likely explanation for the latter observation is that in this study tea consumption merely acted as a marker for a lifestyle that favours the development of cardiovascular disease. Indeed, men with the highest intake of tea and flavonols tended to be manual workers, and they smoked more and ate more fat [208],... 

---