The following is a list of titles of articles about tea and health. There are currently thousands of studies being conducted worldwide in relationship to tea and its health giving properties. For article details and a summary of its content click on the article of interest and it will take you to the details further down the page.

1. Chemopreventive agents in foods.
2. Antioxidants in tea.
3. Protective effect of green tea extract and tea polyphenols against the cytotoxicity of 1, 4-naphthoquinone in isolated rat hepatocytes.
4. The effect of tea on health.
5. Chemistry and applications of green tea.
6. Effects of green tea polyphenols on human intestinal microflora.
7. General chemical composition of green tea and its infusion.
8. Polyphenols of green tea.
9. The effect of whisky and wine consumption on total phenol content and antioxidant capacity of plasma from healthy volunteers.
10. Flavonol glycoside content and composition of tea infusions made from commercially available teas and tea products.
11. Tea flavonoids and cardiovascular diseases: a review.
12. Lignan and isoflavonoid concentrations in tea and coffee.
13. Acute physiological and mood effects of tea.
14. Tea and cancer prevention.
15. Food and free radicals: proceedings of the first symposium, Yamagata, 16 June, 1994
16. The phenolic phytochemicals in wine, fruit and tea: dietary levels, absorption and potential nutritional effects
17. Dietary fat and risk of chronic disease: mechanistic insights from experimental studies
18. Bioactive ingredients: antioxidants and polyphenols in tea.
19. How healthy is tea?
20. Tea and heart disease.
21. Tea antioxidants and health
22. Dietary flavonoids and oxidative stress
23. Diet and cardiovascular disease.
24. The influence of exercise on body composition, and gene-diet interactions are discussed. Phytochemical future. Can health benefits outweigh the regulatory challenges
25. Caffeine: is it safe?
26. Absorption and disposition kinetics of quercetin-glycosides in humans.
27. Nutrition, lipids, health and disease: proceedings of the UNESCO conference, Penang, September 1994.
28. Antioxidants - the case for fruit and vegetables in the diet.
29. Flavonoids and heart disease.
30. Plant flavonoids, especially tea flavonols, are powerful antioxidants using an in vitro oxidation model for heart disease.
31. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases.
32. Dietary flavonoids and risk of coronary heart disease.
33. Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen elderly study.
34. Polyphenols have promising powers for food processors
35. Cancer chemoprevention by green tea polyphenols.
36. Chemistry and applications of green tea.

1. Chemopreventive agents in foods.

Stavric B. Functionality of food phytochemicals: proceedings of the 36th annual meeting of the Phytochemical Society of North America, New Orleans, August 1996.

Johns T. New York Plenum Press 1997 53-88 (256 ref.)

This paper presents an extensive review of phytochemicals, food effect on health, and may be classified as nutraceuticals or functional foods. Special attention is paid to antioxidant components and their beneficial effects against free radicals and oxygen species. The author considers research relating to the following and their physiological effects: the antioxidants (vitamin A, beta-carotene and carotenoids, vitamin C, vitamin E, selenium and phytic acid); polyphenols and flavonoids (caffeine, ellagic, and chlorogenic acids); foods and beverages such as tea, coffee, wine, allium vegetables, cruciferous vegetables, cereal grains and soya beans; food components such as phytoestrogens, protease inhibitors and saponins, palm oil, fish oil, calcium, folic acid, vanillin, and conjugated linoleic acid; and food components that influence the production of detoxifying enzymes.

2. Antioxidants in tea.

Wiseman S.A., Balentine D.A., Frei B.

Critical Reviews in Food Science 1997 37 (8), 705-718 (95 ref.)

This review examines the antioxidant composition and properties of teas. The health benefits of antioxidants are discussed. The free radical scavenging properties of tea antioxidants are described. The relative antioxidant potentials of vitamins, tea beverages, flavonoids, carotenes and xanthophylls are examined. The effects of tea flavonoids on in vivo antioxidant capacity and inhibition of oxidative damage are discussed.

3. Protective effect of green tea extract and tea polyphenols against the cytotoxicity of 1, 4-naphthoquinone in isolated rat hepatocytes.

Miyagawa C., Wu C., Kennedy D.O., Nakatani T., Ohtani K., Sakanaka S., Kim M., Matsui-Yuasa I. B

Bioscience, Biotechnology, and Biochemistry 1997 (November), 61 (11), 1901-1905 (22 ref.)

The polyphenolic components of green tea have been reported to have a range of positive effects that include antioxidant activity, and antimutagenic activity, antitumour and antihypertensive activity. This paper reports a study that demonstrates a protective effect of green tea extract and tea polyphenols against 1,4-naphthoquinone-induced hepatotoxicity in cultured rat hepatocytes. The results suggest that the effect is not related to the prevention of lipid peroxidation. Possible mechanisms of the effect are examined.

4.The effect of tea on health.

Landau J.M., Yang C.S.

Chemistry and Industry 1997 (November 17), (22), 904-906 (33 ref.)

The beneficial health effects of tea are thought to arise from tea polyphenols, which have strong antioxidant properties. This article considers the protective effect of tea against cardiovascular diseases and cancers. For cancer, studies producing negative or positive associations or no significant associations with tea are listed. The bioavailability of the active compounds of tea is also discussed. Finally, the effects of tea on iron and on blood cholesterol levels are considered. The authors conclude that research is beginning to suggest that black and green tea are good for health, but that tea should no be consumed in excessive amounts or at high temperatures.

5. Chemistry and applications of green tea.

Yamamoto T., Juneja L.R., Chu D.C., Kim M.

Boca Raton CRC Press 1997 160 pp

The origins, characteristics, chemical composition, and cultivation of green tea are described. The book then describes the properties of green tea and its component polyphenols. In particular, it covers the metabolism, cancer chemopreventative properties, suppressive effect on uremic toxin formation, inhibitory effect on dental caries and periodontal disease bacteria, regulatory effect on intestinal microflora, deodorizing properties, and ability to cure diarrhea. The physiological activity of theanine, the main amino acid in green tea, is also described.

6. Effects of green tea polyphenols on human intestinal microflora.

Okubo T., Juneja L.R. Chemistry and applications of green tea.

Yamamoto T. Boca Raton CRC Press 1997 109-121 (37 ref.)

The chapter describes the study of the effect of tea polyphenols on intestinal microflora and its metabolites. The study demonstrated that green tea extract has several health benefits through ecologically adjusting the intestinal microflora. The anti-viral effect of tea polyphenols is then described. Tables are presented that show the growth response and inhibition of intestinal microorganisms by green-tea extract, the effects of tea polyphenols on intestinal bacterial cell counts in volunteers, bacteria found in feces, the effect of tea polyphenols on some enzyme activities in feces and on some blood components, and the anti-viral effects of tea polyphenols on human rotavirus.

7. General chemical composition of green tea and its infusion.

Chu D.C., Juneja L.R. Chemistry and applications of green tea.

Yamamoto T. Boca Raton CRC Press 1997 13-22 (35 ref.)

The characteristics and nutritional significance of the chemical components of green tea are described. The components that are described are tea polyphenols, caffeine, amino acids and other nitrogenous compounds, vitamins, inorganic elements (aluminum, fluorine, and manganese), carbohydrates and lipids. Tables are presented that show the chemical composition of tea leaves and its infusion, the effect of the season and the tea species on the polyphenol content, free amino acids in green tea infusion, and inorganic elements in green tea leaves. The biosynthetic pathway of catechins in tea plants is illustrated.

8. Polyphenols of green tea.

Antony J.I.X., Shankaranaryana M.L. I

International Food Ingredients 1997 (October), (5), 47-52 (4pp) (35 ref.)

There is increasing interest in the health benefits of green tea. This article discusses the processing and chemistry of green tea, and considers the nutritional and pharmacological effects attributed to green tea polyphenols. The total polyphenol content of green tea on a dry weight basis may be 25-35%. The vitamin C content of green tea is similar to that of lemon, but most of this is lost during fermentation in production of black tea. Claimed health benefits of green tea include reduction in dental caries, lowering of blood pressure, antioxidant activity, anticarcinogenic effects, and reduction of radiation-induced injury (findings from a mouse study are reported).

9. The effect of whisky and wine consumption on total phenol content and antioxidant capacity of plasma from healthy volunteers.

Duthie G.G., Pedersen M.W., Gardner P.T., Morrice P.C., Jenkinson A. McE., McPhail D.B., Steele G.M.

European Journal of Clinical Nutrition 1998 (October), 52 (10), 733-736 (22 ref.)

Phenolic compounds occur in a wide range of foods (e.g. fruit and vegetables) and beverages (e.g. wine, tea and whisky). It is unclear whether these compounds act as antioxidants in the body. This study determined whether consumption of 100 ml whisky or red wine increased the phenolic content and antioxidant capacity of plasma in male subjects. Plasma samples were monitored for up to 4 hours after consumption. The results showed that consumption of red wine and whisky temporarily increased the phenol content and antioxidative capacity of plasma. This suggests that phenolic compounds act as antioxidants in the body. It supports the theory that increased antioxidant intake and moderate consumption of alcohol reduce the risk of heart disease.

10. Flavonol glycoside content and composition of tea infusions made from commercially available teas and tea products.

Price K.R., Rhodes M.J.C., Barnes K.A.

Journal of Agricultural and Food Chemistry 1998 (July), 46 (7), 2517-2522 (14 ref.)

A high intake of flavonols is correlated with reduced incidence of heart disease, and recent research has indicated that the magnitude of the effect depends upon the type of flavonol. One of the main sources of flavonols in the UK diet is tea, and this paper reports an investigation of the composition and content of flavonol glycosides (FGs) in a range of teas and tea products commonly consumed in the UK. Seven quercetin five kaempferol and two myricetin glycosides were identified. Marked differences, both in the overall levels of (FGÕs) and in the composition of the flavonol fraction, were recorded. Results are presented in detail and discussed with reference to the significance of these differences in relation to the bioavailability and potential bioactivity of these compounds.

11. Tea flavonoids and cardiovascular diseases: a review.

Tijburg L.B.M., Mattern T., Folts J.D., Weisgerber U.M., Katan M.B. C

Critical Reviews in Food Science 1997 37 (8), 771-785 (many ref.)

Tea is thought to have a protective effect against cardiovascular disease through several different mechanisms, one of which is its antioxidant activity. Possible mechanisms of actions are examined in this review. The potential of tea to lower blood lipid levels and to inhibit low-density lipoprotein oxidations and inflammatory reactions are also considered. The role of tea flavonoids is examined.

12. Lignan and isoflavonoid concentrations in tea and coffee.

Mazur W.M., Wahala K., Rasku S., Salakka A., Hase T., Adlercreutz H. B

British Journal of Nutrition 1998 (January), 79 (1), 370-45 (60 ref.) I

In order to investigate the presence of components in tea and coffee that may have a protective effect against certain diseases, a number of commercial samples of black, green, and red teas and several coffees were analyzed by GC-MS. Lignans and isoflavonoids were determined in the teas and coffees, and in brewed tea. High levels of the lignans secoisolariciresinol and matairesinol were observed, but only low levels of isoflavonoids were found. The possible role of these compounds in protecting against diseases such as coronary heart disease and cancer is discussed.

13. Acute physiological and mood effects of tea.

Anon.

Perspectives in Food and Nutrition 1997 (December), (8), 3 (1 ref.)

The physiological effects of consuming tea, coffee, and hot water were measured in 16 healthy individuals. The physiological parameters examined were skin conductance (as a measure of the autonomic nervous system), blood pressure, heart rate, skin temperature, and salivary control. Mood and anxiety were monitored. All hot beverages produced mild stimulation of autonomic nervous system function and rapidly increased skin conductance. The beverages increased skin temperature, with a resultant vasorelaxant effect. The consumption of tea produced a significantly higher skin temperature than hot water or coffee. This indicated that tea produced a faster cooling effect under conditions of heat stress and that it could counteract the constriction of peripheral blood vessels caused by stress. The flavonoids in tea may be responsible for the observed effect. Caffeine increased blood pressure. Consumption of all beverages improved mood and did not increase salivary cortisol levels.

15. Food and free radicals: proceedings of the first symposium, Yamagata, 16 June, 1994

Hiramatsu M., Yoshikawa T., Inoue M.

New York Plenum Press 1997 169 pp

The book describes the molecular mechanisms by which reactive oxygen species deteriorate various types of disease (including rheumatoid arthritis, muscular dystrophy, ischemia/reperfusion injury, digestive disease, cancer, neurological diseases, ageing, diabetes, and inflammation); and the structure and physiochemical properties of a wide variety of natural antioxidants involved in daily food and spices (particularly tea, Gingko bilboa, sesame seeds and lignans, spirulina (blue algae), antioxidant beverage (Beta Catechin), antioxidant biofactor, Mand, Fructus Momordicae, Japanese mushroom, marine bacteria, and plant polyphenols).

16. The phenolic phytochemicals in wine, fruit and tea: dietary levels, absorption and potential nutritional effects

Waterhouse A.L., German J.B., Franke E.N., Walzem R.L., Teissedre P.L., Folts J. Hypernutritious foods.

Finley J.W. Auburndale Agscience Inc. 1996 219-238 (51 ref.)

A link has been found between a reduction in coronary heart disease mortality and consumption of foods rich in phenolic phytochemicals (including wine, foods high in flavonols, and vitamin E). Recent studies of this link are reviewed and the effects of phenolics on atherosclerosis mechanisms, platelets, and vasculature are discussed. Phenolic compounds are defined and the principal dietary sources of flavonoids are reviewed.

17. Dietary fat and risk of chronic disease: mechanistic insights from experimental studies

Weisburger J.H.

Journal of the American Dietetic Association 1997 (July), 97 (7), supplement, S16-S23 (66 ref.)

Although we are encouraged to consume less total fat in the diet in order to decrease the incidence of heart disease, there is evidence to suggest that greater benefits may be achieved with the consumption of protective foods such as bran cereal fibre, vegetables, fruits and tea. further evidence suggests that omega-6 fats, which may decrease the incidence of cardiovascular disease, may increase the incidence of certain cancers. Experiments have shown that omega-3 polyunsaturated oils are protective and that monounsaturated oils have a neutral effect. The increased incidence of fat-related diseases in Japan is highlighted.

18. Bioactive ingredients: antioxidants and polyphenols in tea.

Dreosti I.E.

Nutrition Reviews 1996 (November), 54 (11/2), S51-S58 (62 ref.)

Antioxidants play an important part in reducing the risk of free radical related oxidative damage associated with a number of clinical conditions and degenerative diseases. Studies have provided evidence for the possible protective mechanisms of the A, C, and E vitamins and beta-carotene in reducing the risk of cancer, cardiovascular disease, and cataracts. The polyphenolic antioxidants derived from and including catechin, which are particularly abundant in tea, are discussed. Food sources and general chemistry of polyphenolic derivatives of catechin are considered, together with catechins in green and black tea, bioavailability of tea catechins, tea and cardiovascular disease, tea and cancer, and other putative health benefits from tea.

19. How healthy is tea?

Dreosti I.

Perspectives in Food and Nutrition 1997 (March), 2 (1 ref.)

Black and green teas both contain a number of biologically active compounds, which may have health benefits. Tea consumption has been linked to a reduced risk of some cancers and cardiovascular disease, but the evidence from these trials was not conclusive. The health benefits of tea may be linked to the presence of antioxidants (polyphenolic catechins in green tea and thearubigens and theaflavins in black tea), but further human studies, particularly on the absorption of polyphenols into the human intestine will be required to confirm this theory.

20. Tea and heart disease.

Walsh G.P. Lancet

1997 349 (9053), 735 (5 ref.)

Green tea as consumed in China has been shown to contain polyphenol antioxidants that have an equivalent effect to vitamin E in vitro. The author points out that black tea, as drunk in Europe, also has an antioxidant effect. Trials on the effect of the antioxidant vitamin E in atherosclerotic patients indicated a marked reduction in the number of heart attacks, and a recently reported trial in elderly men in Holland given flavonols also had a beneficial effect. Handbook of antioxidants. Cadenas E., Packer L. New York Marcel Dekker 1996 602pp Many studies have found that antioxidants can decrease the risk of diseases associated with oxidative stress (e.g. heart disease and cancer). Up to date information on the chemical, biochemical and biological properties and clinical aspects of antioxidants: (1) vitamin E, (2) ascorbic acid (3) coenzyme Q, (4) uric acid, (5) carotenoids, (6) vitamin A, (7) flavonoids and polyphenols, (8) herbal antioxidants (tea and Ginkgo bilboa extract), (9) melatonin and aminoindoles, and (10) alpha-lipoic acid, is provided. Where known, the functions and mechanisms of antioxidative activity, and the therapeutic applications of these antioxidants are discussed. In vitro and in vivo evidence to support the beneficial health claims of these antioxidants are presented.

21. Tea antioxidants and health

Weisburger J.H. Handbook of antioxidants. Cadenas E., Packer L. New York Marcel Dekker 1996 469-486 (83 ref.)

Antioxidants have been associated with improved health and reduced risk of some diseases. Tea, which contains antioxidant polyphenols, is thought to improve health. In this chapter, epidemiological studies that show a correlation between tea consumption and reduced risk of coronary heart disease and neoplastic disease (e.g. stomach, lung, pancreatic and breast cancers) are discussed. Consideration is also given to the mechanisms of carcinogenesis, the inhibition of carcinogenesis by tea and the inhibition of virus ineffectively by tea.

22. Dietary flavonoids and oxidative stress

Pietta P., Simonetti P., Roggi C., Brusamolino A., Pellegrini N., Maccarini L., Testolin G. Natural antioxidants and food quality in atherosclerosis and cancer prevention: proceedings of a conference, Helsinki, August 1995. Kumpulainen J.T., Salonen J.T.,

Cambridge RSC 1996 249-255 (20 ref.)

Oxidative stress has been associated with the development of diseases, stress. Consideration is given briefly to the occurrence, analysis, antioxidant properties and kinetics of flavonoids, and its association with cardiovascular disease. Epidemiological studies to investigate an association between flavonoid intake (e.g. supplementation with decaffeinated tea) and factors related to oxidative stress (e.g. cholesterol, fatty acid, beta-carotene and alpha-tocopherol levels in plasma) are discussed. Results suggest that flavonoids increase plasma and red blood cell beta-carotene levels, decrease plasma triglycerides, etc., and may therefore reduce the risk of cardiovascular disease. Epidemiological evidence on potential health properties of flavonoids. Hertog M.G.L. Proceedings of the Nutrition Society 1996 55 (1B), 385-397 (53 ref.) Flavonoids are plant secondary metabolites, which are present in a wide range of fruits and vegetables. Flavonoids are reported to have several beneficial effects on health, and an overview of recent epidemiological studies linking flavonoid intake with the occurrence of several diseases is presented. The content in foods of the flavonoids quercetin, kaempferol, myricetin, apigenin, and luteolin was usually considered in the studies. Sources of flavonoids included fruit and vegetables, wine, and tea, and a reduced risk of cardiovascular disease and cancer was associated with the consumption of flavonoids.

23. Diet and cardiovascular disease.

Food Research Institute, Steinhart C.E., Doyle M.E., Cochrane B.A. Food safety, 1996.

Food Research Institute New York Marcel Dekker 1996 69-119 (338 ref.)

A diet high in cholesterol and saturated fatty acids and low in polyunsaturated fatty acids is reported to increase blood cholesterol and lead to arteriosclerosis and coronary heart disease. This chapter considers the epidemiology of these diseases with reference to dietary components - fat, polyunsaturated fatty acids, trans fatty acids, vitamins and antioxidants, minerals, alcohol, and other foods. risk reduction, cardiovascular risk factors, blood pressure, serum lipids and lipoproteins, other risk factors, and risk factors in children are discussed. Clinical and laboratory studies on the effects of the following dietary components are also reviewed: lipids and fatty acids; saturated fatty acids; monounsaturated fatty acids; trans fatty acids; plant and marine polyunsaturated fatty acids; dietary cholesterol; carbohydrate and fibre; vitamins and antioxidants; minerals; proteins, peptides and amino acids; phospholipids; garlic; mushrooms; tea; herbs and traditional medicines; other foods; and alcohol.

24. The influence of exercise on body composition, and gene-diet interactions are discussed. Phytochemical future. Can health benefits outweigh the regulatory challenges

Horwich Allen A.

Food Product Design 1996 5 (12), 88-100 (8pp) (0 ref.)

Phytochemicals, or functional food ingredients derived from plants, are believed to offer health benefits and are being increasingly added to foods. However, their use by the food industry may be restricted as there are no approved analytical methods or la belling regulations for many of these ingredients. The health benefits of soya (particularly the isoflavones genistein and daidzein), the carotenoids beta-carotene and lycopene, red wine (including grapes and grape juice), green and black tea, and the allicins in onion and garlic are discussed.

25. Caffeine: is it safe?

Shrapnel B.

Perspectives in Food and Nutrition 1996 (3), 10 (2 ref.) his article reviews the sources, consumption and effects of dietary caffeine.

Average caffeine contents of types of coffee, tea, cocoa, and cola soft drinks are stated. The caffeine in tea occurs in complexes with polyphenols, and is absorbed relatively slowly. Other topics considered include metabolism; dependence; and investigations of association with heart disease, pregnancy and breast cancer. the author concludes that caffeine is a thoroughly researched food ingredient, and that at usual levels of intake it has no appreciable effects on health.

26. Absorption and disposition kinetics of quercetin-glycosides in humans.

Hollman P.C.H., van Leeuwen S.D., van der Gaag M.S., Mengelers M.J.B., van Trijp J.M.P., de Vries J.H.M., Katan M.B.

Voeding 1996 57 (3), 28 (3 ref.)

Flavonoids are polyphenols that occur in vegetable products. Quercetin is a flavonol, which in turn is a sub-group of flavonoids. Average daily quercetin intake is around 16 mg per day, mostly from tea, onions, and apples. Quercetin is a strong antioxidant, and possibly prevents the oxidation of LDL. There is an inverse relation between quercetin and death through coronary diseases. Quercetin also slows down the aggregation of blood plates, which could help prevent heart infarct. Quercetin is bound to glycoside, and the article concludes that quercetin-glycosides are absorbed, but that the absorption depends on the type of glycoside.

27. Nutrition, lipids, health and disease: proceedings of the UNESCO conference, Penang, September 1994.

Ong A.S.H., Niki E., Packer L. Champaign

AOCS Press 1995 374 pp.

The book has six sections. Section (i) covers antioxidants including the antioxidant activities of phenolic compounds; nutrition and biochemistry of vitamin E and carotenoids; and the antioxidant components of green tea and evening primrose oil. Section (ii) covers palm oil antioxidants; ubiquinones; the effects of dietary supplement of palm oil; and tocotrienols with reference to cholesterol metabolism, inhibition of HMGcoA reductase, tumor suppressant and including serum lipids and lipoprotein (a) levels; the effect of low-fat and low-protein diets on cholesterol metabolism; cardiovascular disease risk; conjugated diene fatty acids; n-2 polyunsaturated fatty acids; fat-modified eggs; and palm oil consumption effects on urinary excretions of phytoestrogens and oestrogenic steroids. Section (v) covers degenerative and infectious diseases with reference to calories, fat and cancer; antioxidants in the prevention of oral cancer and gastric ulcers; dietary fat and alcoholic liver disease; antioxidants as prophylactics for neurological disorder; and antioxidant nutrients and parasitic and viral infections, malaria, and cardiac arrhythmia. Finally, section (vi) discusses nutrition in populations and includes oils and fat intakes in developing countries; tocopherols and tocotrienols in the US diet; antioxidant intake in India; selenium deficiency and endemic cariomyopathy in China; and serum lipoprotein (a) and coronary heart disease risk in Malaysians.

28. Antioxidants - the case for fruit and vegetables in the diet.

Rice-Evans C., Miller N.J.

British Food Journal 1995 97 (9), 35-40 (24 ref.)

Diets high in fruits and vegetables have been associated with higher life expectancy and reduced risks of heart disease and cancer. These lower risks have been attributed to the antioxidants present in these diets. The evidence supporting the beneficial role of vitamin C, vitamin E and beta-carotene in fruit, vegetables, tea and red wine is examined. Although blood concentrations of the diet-derived antioxidants have shown correlations with cancer incidence and cardiovascular disease, other constituents with beneficial properties might also contribute to these findings.

29. Flavonoids and heart disease.

Anon.

Perspectives in Food and Nutrition 1995 (Summer), 9 (1 ref.)

A study is reported that shows an association between dietary intake of flavonoids and long-term mortality from coronary heart disease. Flavonoids are found in apples, onions, tea, red wine, and other foods of vegetable origin, and have antioxidant activity. The study showed that subjects with higher flavonoid intakes had lower risk of mortality from heart disease.

30. Plant flavonoids, especially tea flavonols, are powerful antioxidants using an in vitro oxidation model for heart disease.

Vinson J.A., Dabbagh Y.A., Serry M.M., Jang J.

Journal of Agricultural and Food Chemistry 1995 43 (11), 2800-2802 (17 ref.)

Are phenol derivatives that are widely distributed in plants, and have been shown to have antioxidant and free radical scavenging activity in foods. This paper presents a comparison of antioxidant activity of flavonoids with that of vitamins C, E and beta-carotene. Tea flavonols were the most powerful natural antioxidants; the antioxidant activity of epigalloepicatechin gallate (EGCG) was 20 times that of ascorbic acid. The model used simulated the oxidation of low density lipoproteins, which is associated with atherosclerosis.

31. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases.

Imai K., Nakachi K.

British Medical Journal 1995 310 (6981), 693-696 (30 re.)

Tea has been investigated as a protective agent against cancer and cardiovascular disease. This study investigated the association between consumption of green tea and various serum markers in a Japanese population. Peripheral blood samples of men aged over 40 years were subjected to biochemical assays and a survey of habits and of daily consumption of green tea was conducted. Increased consumption of green tea was associated with decreased serum concentrations of total cholesterol and triglyceride, an increase in the proportion of high-density-lipoprotein cholesterol, and a decreased proportion of low and very-low-density-lipoprotein cholesterols, producing a decreased atherogenic index. Decreased concentration of hepatological markers in serum were also related to increased consumption of green tea. The authors conclude that green tea might act protectively against liver disorders and cardiovascular disease. Protective effects on the development of cancer are also discussed.

32. Dietary flavonoids and risk of coronary heart disease.

Anon.

Nutrition Reviews 1994 52 (211), 59-68 (12 ref.)

Flavonoids are naturally occurring phenolic compounds found in a wide range of fruits, vegetables and beverages such as tea and wine. Their structure and properties are summarized. It has been suggested that the antioxidant properties of flavonoids may contribute to a reduction in the risk of coronary heart disease. A recent study is reported, in which the flavonoid contents of fruits, vegetables and beverages in the Dutch diet were determined, and intake was related to data on subsequent mortality from coronary heart disease and the incidence of myocardial infarction, obtained from a study of elderly men in an area of the eastern Netherlands. Risk factors such as total serum cholesterol and high-density lipoprotein, age, smoking history, body mass index, physical activity, blood pressure, and dietary intake of saturated fatty acids, cholesterol, vitamins and coffee were also determined. Flavonoids were found to comprise mainly quercetin and kaempferol, and the major dietary contributor was black tea, followed by onions and apples. Multivariate regression analysis revealed a significant relationship between flavonoid intake and risk of mortality from coronary heart disease after adjustment for age and other risk factors. The relationship was stronger than that observed between tea consumption and mortality.

33. Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen elderly study.

Hertog M.G.L., Feskens E.J.M., Hollman P.C.H., Katan M.B., Kromhout D. Lancet 1993 342 (8878), 1007-1011 (29 ref.)

Flavonoids are a group of antioxidant polyphenols that occur naturally in fruits and vegetables and in certain beverages such as wine and tea. In vitro, they are know to inhibit oxidation of low-density lipoprotein and reduce thrombotic tendency. This paper describes a study carried out to examine their effects on atherosclerotic complications in vivo in a large sample of elderly men. The amounts of the flavonoids quercetin, kaempferol, myricetin, apigenin and luteolin were measured in various foods, and these results were used to assess the dietary intake of flavonoids in 805 men, who were then followed up for 5 years. The results indicated that flavonoids in regularly consumed foods might reduce the risk of death from coronary heart disease. Dietary intake of tea, onions and apples was inversely related to coronary heart disease mortality.

34. Polyphenols have promising powers for food processors.

Langley-Danysz P.

RIA 1997 (November), (574), 57-61 (400) (0 ref.) Antioxidant, antimicrobial and anticancer properties have been attributed to polyphenols. This article examines some of the evidence for these claims. It describes the mechanisms involved in antioxidant activity, and the factors that limit the effectiveness of polyphenols. The value of green tea and red wine as sources of polyphenols is discussed.

36. Cancer chemoprevention by green tea polyphenols.

Kim M., Masuda M. chemistry and applications of green tea. Yamamoto T.

Boca Raton CRC Press 1997 61-73 (29 ref.)

Epidemiological studies on the relationship between tea and cancer are reviewed together with laboratory studies using animal models of the link between green tea and cancer. A study of the chemopreventative effect of green tea polyphenols on colon carcino genesis in rats is then described. The study found that epigallocatechin gallate (the main constituent of green tea polyphenols) is responsible for beneficial effects that green tea shows in the reduction of cancer risk. The chemical and biochemical functions of green tea polyphenols are described and include antioxidative activities, trapping carcinogens, inhibition of nitrosation reactions, inhibition of the signals of tumor initiation and promotion. Metabolism of tea polyphenols.

37. Chemistry and applications of green tea.

Takahashi H., Ninomiya M.

Yamamoto T. Boca Raton CRC Press 1997 51-59 (28 ref.)

It has been suggested that green-tea polyphenols may have a protective effect against many adult diseases including cancer. The chapter describes green tea polyphenols with reference to the effects of administration, absorption from the intestine, the effects on the digestive tract, digestive fate and organ distribution, excretion, metabolism (and metabolites in urine, feces, and bile) and metabolic pathway, and toxicity. The proposed metabolic pathways of catechin are illustrated.

38. Tea and cancer prevention.

Wang Z.Y., Chen L., Lee M. -J., Yang C.S. Hypernutritious foods. Finley J.W.

Auburndale Agscience Inc. 1996 239-260 (84 ref.)

The inhibition of tumorigenesis by tea extracts and tea polyphenols has been observed. This chapter examines the available evidence from laboratory and epidemiological studies, and discusses the possible research that is required to elucidate the possible role of tea consumption in the prevention of human cancers is also discussed. A summary of studies of the anti-carcinogenesis effect of tea in experimental animals is tabulated.