ARTICLES BY TOPIC  
 
 
Green Tea May Cut Risk of Heart Disease and Cancer
7/3/2006
Print Share E-Mail Google+ Twitter Facebook

Population study points to an “Asian Paradox”: eastern countries enjoy reduced risks despite high rates of smoking

by Craig Weatherby


You’ve probably heard of the term “French Paradox”, which captures the seeming contradiction that France enjoys a low rate of heart disease, while its national diet is relatively high in saturated fats and cholesterol from cheese, butter, and meats.


Most researchers say that the explanation for this medical conundrum lies in perceiving a fuller, clearer view of the French way of eating:

  • Large amounts of vegetables and fruits
  • Preference for olive over other cooking oils
  • Moderate but routine enjoyment of red wine
  • Relatively small intake of starch
  • More physically activity (in France, it's mostly walking and cycling)

The ample amounts of vegetables, fruits, and red wine in the traditional French diet deliver an abundance of antioxidants and fibers that counter, to a large extent, the negative cardiovascular effects of eating substantial amounts of saturated fats and cholesterol.


We should note that when it comes to heart disease, the French have a smaller preventive hill to climb because they still eat less red meat and highly saturated milk fat than do people in America, Germany, Poland, and other nations with higher rates of heart trouble.


Now, the results of a new evidence review from Yale University suggest that there may be a parallel “Asian paradox”. Its findings suggest that like the French diet, drinking lots of green tea exerts similar heart-protective effects, as well as anti-cancer and other benefits.


Yale study paints picture of “Asian Paradox”

Bauer Sumpio, M.D., is professor and Chief of Vascular Surgery in the Department of Surgery, and the lead author of the new review of more than 100 animal and clinical studies concerning green tea and cardiovascular health or cancer.


He and his team found lower rates of cardiovascular disease and cancer in Asian countries where people smoke heavily but also consume large amounts of green tea on a daily basis (Sumpio BE 2006).


As Dr. Sumpio said in a press release, "We do not yet have a full explanation for the 'Asian paradox' … but we now have some theories." (Note: We’d say that any explanation would need to include not only East Asians’ high intake of green tea, but also their strong proclivity to favor vegetables, fruits, beans, and seafood over meat and dairy.)


The new evidence review from Yale indicates that on average, East Asian peoples drink large amounts of green tea—1.2 liters (just over 2 quarts)—daily. Green tea offers abundant amounts of flavanol antioxidants that display relevant protective effects in lab and animal tests.


Flavanols are members of the larger family of polyphenol compounds, which includes the yellow flavonoids in onions, the colorless catechins and red-brown procyanidins in raw, non-Dutched cocoa powder, and the reddish anthocyanins in berries, eggplant, red cabbage, red apple skins, grapes, and red wine.)


Prominent among these flavanol antioxidants is epigallocatechin gallate—better known as EGCG—which, based on the results of animal tests, and together with its catechin companions in green tea, appears to reduce cardiovascular disease risks in at least eight ways:

  • Lowers total cholesterol levels
  • Raises ratio of HDL (“good”) cholesterol to total cholesterol
  • Helps prevent oxidation of LDL (“bad”) cholesterol
  • Reduces platelet aggregation and expression of adhesion molecules (blood “stickiness”)
  • Reduces production of the unhealthiest forms of cholesterol (VLDLs)
  • Promotes growth and migration of vascular smooth muscle cells
  • Reduces evolution of atherosclerotic lesions
  • Lowers blood pressure (systolic and diastolic)

While the results of clinical studies that tested the effects of tea in humans are mixed—likely due to flaws in study design—the large amount of supportive test tube and animal evidence suggests that the results of the positive trials are more reliable than those of the negative ones.


How much tea is needed for heart health?

Based on the limited evidence available, it takes about 150 mg of tea polyphenols to trigger a rapid antioxidant effect in human blood, and 500 mg to produce longer-term changes that protect cardiovascular health. A cup of brewed tea usually contains about 172 mg of flavonoids, so it takes one cup to produce short-term cardiovascular benefits and three to four cups per day to elicit long-term benefits.


Extra dark chocolate is also rich in catechin-class flavanols, so you can consider their cardiac benefits a sound reason to enjoy this mouth-watering treat in moderation.


Tea and cancer: why it helps

Dr. Sumpio noted that the findings of most studies suggest that the EGCG in green tea may reduce the risk of hormone-related cancers, including breast, ovarian, and prostate cancers.


Green tea appears to fight cancer by influencing circulating hormone levels, and by modulating several “signal transduction” pathways in human cells in ways that inhibit dangerous proliferation of cells. As a University of Wisconsin team reported (Khan N 2006), green tea’s impact on signal transduction pathways imparts “…strong cancer chemopreventive as well as therapeutic effects.”


Dr. Sumpio also noted that green tea appears to offer a number of other health benefits:

  • Enhance gastrointestinal, kidney, liver, tooth, gum, and pancreatic health
  • Protect skin and eyes from UV damage
  • Alleviate diseases with an inflammatory component (arthritis, allergies)
  • Reduce diabetes symptoms
  • Help fight bacterial and viral infections
  • Reduce cavities
  • Improve psychological health

While he said that kicking the tobacco habit remains the best way to prevent cardiovascular disease and cancer in a population of heavy smokers, Dr. Sumpio made this confident assessment: "The evidence is strong that green tea consumption is a useful dietary habit to lower the risk for, as well as treat, a number of chronic diseases."



Sources

  • Sumpio BE, Cordova AC, Berke-Schlessel DW, Qin F, Chen QH. Green tea, the "Asian paradox," and cardiovascular disease. J Am Coll Surg. 2006 May;202(5):813-25. Review.
  • Kris-Etherton PM, Keen CL. Evidence that the antioxidant flavonoids in tea and cocoa are beneficial for cardiovascular health. Curr Opin Lipidol. 2002 Feb;13(1):41-9. Review.
  • Stangl V, Lorenz M, Stangl K. The role of tea and tea flavonoids in cardiovascular health. Mol Nutr Food Res. 2006 Feb;50(2):218-28. Review.
  • Hernandez Figueroa TT, Rodriguez-Rodriguez E, Sanchez-Muniz FJ. [The green tea, a good choice for cardiovascular disease prevention?] Arch Latinoam Nutr. 2004 Dec;54(4):380-94. Review. Spanish.
  • Li L, Stillemark-Billton P, Beck C, Bostrom P, Andersson L, Rutberg M, Ericsson J, Magnusson B, Marchesan D, Ljungberg A, Boren J, Olofsson SO. Epigallocatechin gallate increases the formation of cytosolic lipid droplets and decreases the secretion of apoB-100 VLDL. J Lipid Res. 2006 Jan;47(1):67-77. Epub 2005 Oct 14.
  • Yee WL, Wang Q, Agdinaoay T, Dang K, Chang H, Grandinetti A, Franke AA, Theriault A. Green tea catechins decrease apolipoprotein B-100 secretion from HepG2 cells. Mol Cell Biochem. 2002 Jan;229(1-2):85-92.
  • Yang TT, Koo MW. Hypocholesterolemic effects of Chinese tea. Pharmacol Res. 1997 Jun;35(6):505-12.
  • Chisaka T, Matsuda H, Kubomura Y, Mochizuki M, Yamahara J, Fujimura H. The effect of crude drugs on experimental hypercholesteremia: mode of action of (-)-epigallocatechin gallate in tea leaves. Chem Pharm Bull (Tokyo). 1988 Jan;36(1):227-33.
  • Matsuda H, Chisaka T, Kubomura Y, Yamahara J, Sawada T, Fujimura H, Kimura H. Effects of crude drugs on experimental hypercholesterolemia. I. Tea and its active principles. J Ethnopharmacol. 1986 Sep;17(3):213-24.
  • Chyu KY, Babbidge SM, Zhao X, Dandillaya R, Rietveld AG, Yano J, Dimayuga P, Cercek B, Shah PK. Differential effects of green tea-derived catechin on developing versus established atherosclerosis in apolipoprotein E-null mice. Circulation. 2004 May 25;109(20):2448-53. Epub 2004 May 10.
  • Khan N, Afaq F, Saleem M, Ahmad N, Mukhtar H. Targeting multiple signaling pathways by green tea polyphenol (-)-epigallocatechin-3-gallate. Cancer Res. 2006 Mar 1;66(5):2500-5. Review.
  • Wu AH, Yu MC. Tea, hormone-related cancers and endogenous hormone levels. Mol Nutr Food Res. 2006 Feb;50(2):160-9. Review.
  • Na HK, Surh YJ. Intracellular signaling network as a prime chemopreventive target of (-)-epigallocatechin gallate. Mol Nutr Food Res. 2006 Feb;50(2):152-9. Review.
  • Fisher ND, Hollenberg NK. Flavanols for cardiovascular health: the science behind the sweetness. J Hypertens. 2005 Aug;23(8):1453-9. Review.
  • Murphy KJ, Chronopoulos AK, Singh I, Francis MA, Moriarty H, Pike MJ, Turner AH, Mann NJ, Sinclair AJ. Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function. Am J Clin Nutr. 2003 Jun;77(6):1466-73.
  • Fisher ND, Hughes M, Gerhard-Herman M, Hollenberg NK. Flavanol-rich cocoa induces nitric-oxide-dependent vasodilation in healthy humans. J Hypertens. 2003 Dec;21(12):2281-6.

Special Offers • Recipes
Nutrition & Eco News
RECENT ARTICLES
For orders, questions, or assistance call 800-608-4825 any day or time. © 2014 Vital Choice Wild Seafood & Organics, Inc. All Rights Reserved