Flavonoid cardiovascular health

Reed, J., Cranberry flavonoids, atherosclerosis and cardiovascular health, Crit. Rev. Food Sci. Nutr., 42, 301, 2002. 

Geleijnse JM and Hollman PCh. 2008. Flavonoids and cardiovascular health which compounds, what mechanisms Am J Clin Nutr 88(1) 12—13. 

Kris-Etherton PM and Keen CL. 2002. Evidence that the antioxidant flavonoids in tea and cocoa are beneficial for cardiovascular health. Curr Opin Lipidol 13(1) 41—49. 

Geleijnse et al., 2002 Mukamal et al., 2002], Mechanisms by which these compounds exert their cardiovascular protective effects are still unknown. It is widely hypothesized that dietary flavonoids improve cardiovascular health and may help to prevent cardiovascular diseases/events by inhibiting pathogenic processes such as oxidative stress (lipid and protein peroxidation), inflammation, endothelial dysfunction, and platelet activation [Nijveldt et al., 2001]. 

Studies from several laboratories including ours have revealed that quercetin is able to prevent or revert hypertension and endothelial dysfunction, and we believe that this is a fundamental mechanism involved in the protective effects of flavonoids on cardiovascular health. Oral administration of quercetin (5 or... 

Hertog, M.G.L. and Katan, M.B. 1998. Quercetin in foods, cardiovascular disease, and cancer, in Flavonoids in Health and Disease, eds., C.A. Rice-Evans and L. Packer, New York Marcel Dekker, Inc., pp. 447 -67. 

Riemersma RA, Rice-Evans CA, Tyrrell RM, Clifford MN, Lean ME. Tea flavonoids and cardiovascular health. Q J Med 2001 94 277-282. 

Stangl, V., Lorenz, M., and Stangl, K. 2006. The role oftea and tea flavonoids in cardiovascular health , Molecular, Nutrition and Food Research., 50 218—228. 

Most research on flavonoids and health has focused on quercetin due to its antioxidant potency and potential role in cardiovascular disease. However, the diverse and broad nature of flavonoids means that subclasses other than the flavonols may be more important to human health since they appear to be more bioavailable and thus have a greater potential to protect against the various mechanisms involved in aging and disease development. 

Tea flavonoids, or tea extracts, have been linked to benefits in reducing the risk of certain cancers and cardiovascular diseases in experimental animals. However, epidemiological studies have produced inconsistent evidence in the relationship between tea drinking and cancer (Blot et a/., 1997 Goldbohm etal, 1996 Hertog eta/., 1997 Yang eta/., 1996). Therefore, further research is needed before definitive conclusions on the impact of tea consumption upon the cancer risk in humans can be reached. The metabolites of catechins and flavonols after consumption of tea infusions have scarcely been investigated, and thus more research is needed as to the role of those compounds in the reported health benefits of tea consumption. 

Many flavonoids have antioxidant properties and as such are thought to protect humans against cardiovascular disease and cancer. Foods containing flavonoids (e.g., green tea, soy, and red wine) are touted as beneficial for health. 

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],... 

Tea is another important dietary source for flavonoids, In fact, about half of the flavonoid intake in western populations is derived from black tea. Tea was the major source of flavonoids in the Dutch [6,13] and Welsh studies [17]. Only a small number of studies investigated the association between tea consumption and cardiovascular disease risk. No association between tea consumption and cardiovascular disease risk were reported in Scottish men and women [28] and in U.S. men in the Health Professionals follow-up study [29]. However, in a Norwegian population an inverse association was reported between tea intake, serum cholesterol, and mortality from coronary heart disease [30]. Several studies reported that tea consumption did not affect plasma antioxidant activity [31] and hemostatic factors [32]. However, a recent prospective study (the Rotterdam study) of 3,454 men and women 55 years and older followed for 2 to 3 years, showed a significant, inverse association of tea intake with severe (> 5 cm the length of the calcified area) aortic atherosclerosis. Odds ratios decreased approximately 70 % for drinking more than 500 mL/day (4 cups per day). The associations were stronger in women than in men. However, the risk reductions for moderate and mild atherosclerosis were only weak or absent [33]. 

The observation of a lower incidence of coronary heart disease (CHD) and certain types of cancers in the Mediterranean area led to the hypothesis that a diet rich in grain, legumes, fresh fruits and vegetables, wine in moderate amounts, and olive oil was beneficial to human health. To date, this effect has been mainly attributed to the low saturated fat intake of the Mediterranean diet and its high proportion of monounsaturates, which indeed may favorably affect the plasma lipid and lipoprotein profiles. Nevertheless, other components of the diet, such as fiber, vitamins, flavonoids, and phenols, may play an important role in disease prevention, acting on different cardiovascular variables. 

Aviram, M., Vaya, J., and Fuhrman, B., Licorice root flavonoid antioxidants reduce LDL oxidation and attenuate cardiovascular diseases, in Herbal medicines Molecular basis of biological activity and health, Packer L., Halliwel B., and Nam Qng, C. (eds.), Marcel Dekker, New York, 27, 595, 2004. 

Numerous health benefits have been reported or claimed for flavonoids and isoflavones, such as in cancer prevention, cardiovascular effects, and relief of menopausal syndromes. However, concerns have been raised about potential adverse effects, such as enhancement of reproductive organs and anti-thyroid effects. In order to evaluate potential beneficial or hazardous health effects from flavonoids. 

The rich red color of strawberries comes from numerous phytochemicals of the polyphenol family and its major subgroup, flavonoids, which are densely found in strawberries. One flavonoid class in particular, antho-cyanins, accounts for most of the red pigmentation of strawberries, but also present are ellagic acid, ellagitannins, catechins, and cinnamic acid, each having significant health research interest. In preliminary laboratory tests, these strawberry polyphenols are showing evidence that they may lower the risk of inflammation, cancer, and cardiovascular diseases. 

Bazzano LA, He J, Odgden LG, et al. Fruit and vegetable intake and risk of cardiovascular disease in US adults the first National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study. Am J Clin Nutr 2002 76 93-99. Knekt P, Jarvinen R, Reunanen A, and Maatela J. Flavonoid intake and coronary mortality in Finland a cohort study. Br Med J. 1996 312 478-481. 

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