Health effects of tea

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1912 advertisement for tea in the Sydney Morning Herald, describing its supposed health benefits Robur tea advert 1912.png
1912 advertisement for tea in the Sydney Morning Herald , describing its supposed health benefits

The health effects of tea have been studied throughout human history. Although health benefits have been assumed throughout the history of using Camellia sinensis as a common beverage, there is no high-quality evidence that consuming tea confers significant benefits other than possibly increasing alertness, an effect caused by caffeine in the tea leaves. [1] [2] In clinical research conducted over the early 21st century, tea has been studied extensively for its potential to lower the risk of human diseases, but there is no good scientific evidence to support any therapeutic uses. A small number of studies suggests that both green and black tea might have beneficial effects on some heart disease risk factors, including blood pressure and cholesterol. The research has limitations though, including how the data was evaluated and differences in study populations, so no definite conclusions have been reached. [2]

Contents

In regions without access to safe drinking water, boiling water to make tea is effective for reducing waterborne diseases by destroying pathogenic microorganisms.

By constituents or substances

Aluminum, iron and other metals

Tea drinking accounts for a high proportion of aluminum in the human diet. [3] The levels are safe, but there has been some concern that aluminum traces may be associated with Alzheimer's disease. A 2013 study additionally indicated that some teas contained lead (mostly Chinese) and aluminum (Indian/Sri Lanka blends, China). [4] There is still insufficient evidence to draw firm conclusions on this subject. [5]

Most studies have found no association between tea intake and iron absorption. [6] However, drinking excessive amounts of black tea may inhibit the absorption of iron, and may harm people with anaemia. [7]

Concerns have been raised about the traditional method of over-boiling tea to produce a decoction, which may increase the amount of environmental contaminants released and consumed. [8]

Fluoride exposure

All tea leaves contain fluoride; however, mature leaves contain as much as 10 to 20 times the fluoride levels of young leaves from the same plant. [9] [10]

The fluoride content of a tea leaf depends on the leaf picking method used and the fluoride content of the soil from which it has been grown; tea plants absorb this element at a greater rate than other plants. Care in the choice of the location where the plant is grown may reduce the risk. [11] It is speculated that hand-picked tea would contain less fluoride than machine-harvested tea, because there is a much lower chance of harvesting older leaves during the harvest process. A 2013 British study of 38 teas found that cheaper UK supermarket tea blends had the highest levels of fluoride with about 580 mg per kilogram, green teas averaged about 397 mg per kg and pure blends about 132 mg per kg. The researchers suggested that economy teas may use older leaves which contain more fluoride. They calculated a person drinking a litre of economy tea per day would consume about 6 mg of fluoride, above the recommended average dietary intake level of 3–4 mg of fluoride per day, but below the maximum tolerable amount of 10 mg of fluoride per day. [12] Brick tea, made from fallen leaves, old leaves and stems has the highest levels. [13]

One study indicated that green tea leaves have an average fluoride concentration of 52 mg/kg, and approximately 89% of the fluoride was released from the leaves into tea after brewing. [14]

Oxalates

Tea contains oxalate, overconsumption of which can cause kidney stones, as well as binding with free calcium in the body. The bioavailability of oxalate from tea is low, thus a possible negative effect requires a large intake of tea. [15] Massive black tea consumption has been linked to kidney failure due to its high oxalate content (acute oxalate nephropathy). [16] [17]

Theanine and caffeine

Tea also contains theanine and the stimulant caffeine at about 3% of its dry weight, translating to between 30 mg and 90 mg per 8 US fluid ounces (240 mL) depending on type, brand [18] and brewing method. [19] Tea also contains small amounts of theobromine and theophylline. [20] Dry tea has more caffeine by weight than dry coffee; nevertheless, more dry coffee than dry tea is used in typical drink preparations, [21] which results in a cup of brewed tea containing significantly less caffeine than a cup of coffee of the same size.

The caffeine in tea is a mild diuretic. However, the British Dietetic Association has suggested that tea can be used to supplement normal water consumption, and that "the style of tea and coffee and the amounts we drink in the UK are unlikely to have a negative effect [on hydration]". [22]

By conditions

Cognitive effects

Drinking caffeinated tea may improve mental alertness due to the effects of caffeine. [1]

Cancer

In 2011, the US Food and Drug Administration reported that there was little evidence to support the claim that green tea consumption may reduce the risk of breast and prostate cancer. [23]

A 2010 report by the US National Cancer Institute stated that epidemiological studies and the few clinical trials of tea for the prevention of cancer were inconclusive. [24] The institute "does not recommend for or against the use of tea to reduce the risk of any type of cancer." ... "Inconsistencies in study findings regarding tea and cancer risk may be due to variability in tea preparation, tea consumption, the bioavailability of tea compounds (the amounts that can be absorbed by the body), lifestyle differences, and individual genetic differences." [24] Though there is some positive evidence for risk reduction of breast, prostate, ovarian, and endometrial cancers with green tea, it is weak and inconclusive. [25]

Meta-analyses of observational studies have concluded that black tea consumption does not appear to protect against the development of oral cancers in Asian or Caucasian populations, the development of esophageal cancer or prostate cancer in Asian populations, or the development of lung cancer. [26] [27] [28] [29] [30] In 2018, a meta-analysis based on 14 case-control studies found that tea consumption appears protective of oral cancer with a greater decrease in risk occurring with a larger intake (except for black tea and American people). [31]

The consumption of very hot tea could increase the risk of esophageal cancer. [32]

Cardiovascular disease

In preliminary long-term clinical studies, black tea consumption showed evidence for providing a small reduction in the risk of stroke, [33] [34] whereas, in another review, green tea and black tea did not have significant effects on the risk of coronary heart disease. [35] Two reviews of randomized controlled trials concluded that long-term consumption of black tea slightly lowers systolic and diastolic blood pressures (about 1–2 mmHg), a finding based on limited evidence. [36] [37] A 2013 Cochrane review found some evidence of benefit from tea consumption on cardiovascular markers (total and LDL cholesterol), though more research is needed. [36]

Fracture risk

Tea consumption does not appear to affect the risk of bone fracture including hip fractures or fractures of the humerus in men or women. [38]

Weight loss

Although green tea is commonly believed to be a weight loss aid, there is no good evidence that its long-term consumption has any meaningful benefit in helping overweight or obese people to lose weight, or that it helps to maintain a healthy body weight. [39] [40] Use of green tea for attempted weight loss carries a small risk of adverse effects, such as nausea, constipation, and stomach discomfort. [39]

See also

Related Research Articles

<span class="mw-page-title-main">Caffeine</span> Central nervous system stimulant

Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class and is the most commonly consumed psychoactive substance globally. It is mainly used for its eugeroic, ergogenic, or nootropic properties. Caffeine can supposedly, after a person grows used to it, have a lesser effect on wakefulness. {{Citationneeded.}} Caffeine acts by blocking binding of adenosine at a number of adenosine receptor types, inhibiting the centrally depressant effects of adenosine and enhancing the release of acetylcholine. Caffeine has a three-dimensional structure similar to that of adenosine, which allows it to bind and block its receptors. Caffeine also increases cyclic AMP levels through nonselective inhibition of phosphodiesterase, increases calcium release from intracellular stores, and antagonises GABA receptors, although these mechanisms typically occur at concentrations beyond usual human consumption.

Fluoride is an inorganic, monatomic anion of fluorine, with the chemical formula F−
, whose salts are typically white or colorless. Fluoride salts typically have distinctive bitter tastes, and are odorless. Its salts and minerals are important chemical reagents and industrial chemicals, mainly used in the production of hydrogen fluoride for fluorocarbons. Fluoride is classified as a weak base since it only partially associates in solution, but concentrated fluoride is corrosive and can attack the skin.

<span class="mw-page-title-main">Green tea</span> Unoxidized tea

Green tea is a type of tea that is made from Camellia sinensis leaves and buds that have not undergone the same withering and oxidation process which is used to make oolong teas and black teas. Green tea originated in China, and since then its production and manufacture has spread to other countries in East Asia.

Caffeinism is a state of intoxication caused by excessive consumption of caffeine. This intoxication covers a variety of unpleasant physical and mental symptoms associated with the consumption of excessive amounts of caffeine.

<span class="mw-page-title-main">Caffeinated drink</span> Type of drink

A caffeinated drink, or caffeinated beverage, is a drink that contains caffeine, a stimulant that is legal practically all over the world. Some are naturally caffeinated while others have caffeine added as an ingredient.

<span class="mw-page-title-main">Water fluoridation</span> Addition of fluoride to a water supply to reduce tooth decay

Water fluoridation is the addition of fluoride to a public water supply to reduce tooth decay. Fluoridated water contains fluoride at a level that is effective for preventing cavities; this can occur naturally or by adding fluoride. Fluoridated water operates on tooth surfaces: in the mouth, it creates low levels of fluoride in saliva, which reduces the rate at which tooth enamel demineralizes and increases the rate at which it remineralizes in the early stages of cavities. Typically a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $1.32 per person-year. Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. In 2011, the World Health Organization suggested a level of fluoride from 0.5 to 1.5 mg/L, depending on climate, local environment, and other sources of fluoride. In 2024, the Department of Health and Human Services' National Toxicology Program found that water fluoridation levels above 1.5 mg/L are associated with lower IQ in children. In 2024, U.S. court rulings have raised concerns about the potential health risks of water fluoridation, including findings by the EPA and new risk assessments that suggest the benefits may be waning. Bottled water typically has unknown fluoride levels.

Decaffeination is the removal of caffeine from coffee beans, cocoa, tea leaves, and other caffeine-containing materials. Decaffeinated products are commonly termed by the abbreviation decaf. Decaffeinated drinks contain typically 1–2% of the original caffeine content, but sometimes as much as 20%.

Recurrent miscarriage or recurrent pregnancy loss (RPL) is the spontaneous loss of 2-3 pregnancies that is estimated to affect up to 5% of women. The exact number of pregnancy losses and gestational weeks used to define RPL differs among medical societies. In the majority of cases, the exact cause of pregnancy loss is unexplained despite genetic testing and a thorough evaluation. When a cause for RPL is identified, almost half are attributed to a chromosomal abnormality. RPL has been associated with several risk factors including parental and genetic factors, congenital and acquired anatomical conditions, lifestyle factors, endocrine disorders, thrombophila, immunological factors, and infections. The American Society of Reproductive Medicine recommends a thorough evaluation after 2 consecutive pregnancy losses; however, this can differ from recommendations by other medical societies. RPL evaluation can be evaluated by numerous tests and imaging studies depending on the risk factors. These range from cytogenetic studies, blood tests for clotting disorders, hormone levels, diabetes screening, thyroid function tests, sperm analysis, antibody testing, and imaging studies. Treatment is typically tailored to the relevant risk factors and test findings. RPL can have a significant impact on the psychological well-being of couples and has been associated with higher levels of depression, anxiety, and stress. Therefore, it is recommended that appropriate screening and management be considered by medical providers.  

<span class="mw-page-title-main">Caffeine dependence</span> Medical condition

Caffeine dependence is a condition characterized by a set of criteria, including tolerance, withdrawal symptoms, persistent desire or unsuccessful efforts to control use, and continued use despite knowledge of adverse consequences attributed to caffeine. It can appear in physical dependence or psychological dependence, or both. Caffeine is one of the most common additives in many consumer products, including pills and beverages such as caffeinated alcoholic beverages, energy drinks, pain reliever medications, and colas. Caffeine is found naturally in various plants such as coffee and tea. Studies have found that 89 percent of adults in the U.S. consume on average 200 mg of caffeine daily. One area of concern that has been presented is the relationship between pregnancy and caffeine consumption. Repeated caffeine doses of 100 mg appeared to result in smaller size at birth in newborns. When looking at birth weight however, caffeine consumption did not appear to make an impact.

<span class="mw-page-title-main">Milk tea</span> Beverage mainly composed of tea and milk

Milk tea refers to several forms of beverage found in many cultures, consisting of some combination of tea and milk. The term milk tea is used for both hot and cold drinks that can be combined with various kinds of milks and a variety of spices. This is a popular way to serve tea in many countries, and is the default type of tea in many South Asian countries. Beverages vary based on the amount of each of these key ingredients, the method of preparation, and the inclusion of other ingredients Milk tea is the default type of tea in India and Pakistan and referred to as chai.

<span class="mw-page-title-main">Theanine</span> Amino acid

Theanine, commonly known as L-theanine and sometimes L-gamma-glutamylethylamide or N5-ethyl-L-glutamine, is an amino acid analogue of the proteinogenic amino acids L-glutamate and L-glutamine and is found primarily in particular plant and fungal species. It was discovered as a constituent of green tea in 1949 and isolated from gyokuro leaves in 1950, thus rendering it a natural product. It constitutes about 1–2% of the dry weight of green tea leaves.

<span class="mw-page-title-main">Alcohol and cancer</span> Relationship between cancer and the consumption of alcohol

Alcohol and cancer have a complex relationship. Alcohol causes cancers of the oesophagus, liver, breast, colon, oral cavity, rectum, pharynx, and larynx, and probably causes cancers of the pancreas. Cancer risk can occur even with light to moderate drinking. The more alcohol is consumed, the higher the cancer risk, and no amount can be considered completely safe.

<span class="mw-page-title-main">Nutrition and pregnancy</span> Nutrient intake and dietary planning undertaken before, during and after pregnancy

Nutrition and pregnancy refers to the nutrient intake, and dietary planning that is undertaken before, during and after pregnancy. Nutrition of the fetus begins at conception. For this reason, the nutrition of the mother is important from before conception as well as throughout pregnancy and breastfeeding. An ever-increasing number of studies have shown that the nutrition of the mother will have an effect on the child, up to and including the risk for cancer, cardiovascular disease, hypertension and diabetes throughout life.

The health effects of coffee include various possible health benefits and health risks.

<span class="mw-page-title-main">Diet and cancer</span> Connections between dietary habits and cancer

Many dietary recommendations have been proposed to reduce the risk of cancer, few have significant supporting scientific evidence. Obesity and drinking alcohol have been correlated with the incidence and progression of some cancers. Lowering the consumption of sweetened beverages is recommended as a measure to address obesity.

<span class="mw-page-title-main">Epigallocatechin gallate</span> Catechin (polyphenol) in tea

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin.

<span class="mw-page-title-main">Weight management</span> Techniques for maintaining body weight

Weight management refers to behaviors, techniques, and physiological processes that contribute to a person's ability to attain and maintain a healthy weight. Most weight management techniques encompass long-term lifestyle strategies that promote healthy eating and daily physical activity. Moreover, weight management involves developing meaningful ways to track weight over time and to identify the ideal body weights for different individuals.

<span class="mw-page-title-main">Phenolic content in tea</span> Natural plant compounds

The phenolic content in tea refers to the phenols and polyphenols, natural plant compounds which are found in tea. These chemical compounds affect the flavor and mouthfeel of tea. Polyphenols in tea include catechins, theaflavins, tannins, and flavonoids.

<span class="mw-page-title-main">Sweetened beverage</span> Type of beverage

Sugar-sweetened beverages (SSB) are beverages with added sugar. They have been described as "liquid candy". Added sugars include brown sugar, corn sweetener, corn syrup, dextrose, fructose, high fructose corn syrup, honey, invert sugar, lactose, malt syrup, maltose, molasses, raw sugar, sucrose, trehalose, and turbinado sugar. Naturally occurring sugars, such as those in fruit or milk, are not considered to be added sugars. Free sugars include monosaccharides and disaccharides added to foods and beverages by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates.

<span class="mw-page-title-main">Black tea</span> Type of tea

Black tea is a type of tea that is more oxidized than oolong, yellow, white, and green teas. Black tea is generally stronger in flavour than other teas. All five types are made from leaves of the shrub Camellia sinensis, though Camellia taliensis is also rarely used.

References

  1. 1 2 "Black tea". MedlinePlus. US National Library of Medicine. 10 June 2022.
  2. 1 2 "Green tea". National Center for Complementary and Integrative Health, US National Institutes of Health. October 2020.
  3. ↑ Streeta R, Drábeka O, Szákováb J, Mládkováa L (2007). "Total content and speciation of aluminium in tea leaves and tea infusions". Food Chemistry. 104 (4): 1662–1669. doi:10.1016/j.foodchem.2007.03.019.
  4. ↑ Schwalfenberg, Gerry; Genuis, Stephen J.; Rodushkin, Ilia (2013). "The Benefits and Risks of Consuming Brewed Tea: Beware of Toxic Element Contamination". Journal of Toxicology: 1–8. doi: 10.1155/2013/370460 . PMC   3821942 . PMID   24260033.
  5. ↑ Karak T, Bhagat RM (2010). "Trace elements in tea leaves, made tea and tea infusion: A review". Food Research International (Review). 43 (9): 2234–2252. doi:10.1016/j.foodres.2010.08.010.
  6. ↑ Beck KL, Conlon CA, Kruger R, Coad J (2014). "Dietary determinants of and possible solutions to iron deficiency for young women living in industrialized countries: a review". Nutrients. 6 (9): 3747–76. doi: 10.3390/nu6093747 . PMC   4179187 . PMID   25244367.
  7. ↑ Wierzejska R (2014). "Tea and health—a review of the current state of knowledge". Przegl Epidemiol (Review). 68 (3): 501–6, 595–9. PMID   25391016.
  8. ↑ Abd El-Aty AM, Choi JH, Rahman MM, Kim SW, Tosun A, Shim JH (2014). "Residues and contaminants in tea and tea infusions: a review". Food Addit Contam Part a Chem Anal Control Expo Risk Assess. 31 (11): 1794–804. doi:10.1080/19440049.2014.958575. PMID   25164107. S2CID   21497059.
  9. ↑ Lung SC, Cheng HW, Fu CB (2008). "Potential exposure and risk of fluoride intakes from tea drinks produced in Taiwan". J Expo Sci Environ Epidemiol. 18 (2): 158–66. doi: 10.1038/sj.jes.7500574 . PMID   17410113.
  10. ↑ Malinowska E, Inkielewicz I, Czarnowski W, Szefer P (2008). "Assessment of fluoride concentration and daily intake by human from tea and herbal infusions". Food Chem. Toxicol. 46 (3): 1055–61. doi:10.1016/j.fct.2007.10.039. PMID   18078704.
  11. ↑ Jianyun Ruan; Ming H. Wong (2001). "Accumulation of Fluoride and Aluminium Related to Different Varieties of Tea Plant". Environmental Geochemistry and Health. 23 (1): 53–63. doi:10.1023/A:1011082608631. S2CID   127931635.
  12. ↑ (25 July 2013) Do fluoride levels in cheap tea pose a health risk? British National Health Service "Choices, Retrieved 26 July 2013
  13. ↑ Fung KF, Zhang ZQ, Wong JW, Wong MH (1999). "Fluoride contents in tea and soil from tea plantations and the release of fluoride into tea liquor during infusion". Environmental Pollution. 104 (2): 197–205. doi:10.1016/S0269-7491(98)00187-0.
  14. ↑ Maleki, Afshin; Daraei, Hiua; Mohammadi, Elham; Zandi, Shiva; Teymouri, Pari; Mahvi, Amir Hossien; Gharibi, Fardin (28 March 2016). "Daily Fluoride Intake from Iranian Green Tea: Evaluation of Various Flavorings on Fluoride Release". Environmental Health Insights. 10: 59–63. Bibcode:2016EnvHI..10S8511M. doi:10.4137/EHI.S38511. PMC   4811265 . PMID   27042093.
  15. ↑ Michael Liebman; Shawnna Murphy (2007). "Low oxalate bioavailability from black tea". Nutrition Research. 27 (5): 273–278h. doi:10.1016/j.nutres.2007.04.004.
  16. ↑ Emery, Gene (1 April 2015). "Massive tea consumption linked to kidney failure". Reuters . Archived from the original on 7 March 2018. Retrieved 13 December 2020.
  17. ↑ Elahe Izadi washingtonpost.com Why drinking too much iced tea caused this man’s kidneys to fail 3 April 2015
  18. ↑ Bennett Alan Weinberg; Bonnie K. Bealer (2001). The World of Caffeine: The Science and Culture of the World's Most Popular Drug . Routledge. p.  228. ISBN   978-0-415-92722-2 . Retrieved 20 September 2008.
  19. ↑ M. B. Hicks, Y-H. P. Hsieh, L. N. Bell, Tea preparation and its influence on methylxanthine concentration, Food Research International 29(3–4) 325–330 (1996)
  20. ↑ Graham H. N.; Green tea composition, consumption, and polyphenol chemistry; Preventive Medicine21(3):334-50 (1992)
  21. ↑ "Caffeine and Tea Information". Stash Tea. Archived from the original on 13 May 2011. Retrieved 15 July 2009.
  22. ↑ BDA Supports Dehydration Awareness Week with some Handy Tips (PDF). British Dietetic Association, June 2011.
  23. ↑ Food and Drug Administration (24 February 2011). "Summary of Qualified Health Claims Subject to Enforcement Discretion". Food and Drug Administration . Retrieved 9 October 2014.
  24. 1 2 National Cancer Institute (17 November 2010). "Tea and Cancer Prevention: Strengths and Limits of the Evidence" . Retrieved 7 December 2022.
  25. ↑ Johnson R, Bryant S, Huntley AL (December 2012). "Green tea and green tea catechin extracts: an overview of the clinical evidence". Maturitas (Review). 73 (4): 280–7. doi: 10.1016/j.maturitas.2012.08.008 . PMID   22986087. Green tea consumption does help reduce body weight and aid weight management as shown in short term RCTs (12 weeks) but not to a clinically relevant level.
  26. ↑ Wang W, Yang Y, Zhang W, Wu W (April 2014). "Association of tea consumption and the risk of oral cancer: a meta-analysis". Oral Oncol (Meta-Analysis). 50 (4): 276–81. doi:10.1016/j.oraloncology.2013.12.014. PMID   24389399.
  27. ↑ Wang Y, Yu X, Wu Y, Zhang D (November 2012). "Coffee and tea consumption and risk of lung cancer: a dose-response analysis of observational studies". Lung Cancer (Meta-Analysis). 78 (2): 169–70. doi:10.1016/j.lungcan.2012.08.009. PMID   22964413.
  28. ↑ Zheng J, Yang B, Huang T, Yu Y, Yang J, Li D (June 2011). "Green tea and black tea consumption and prostate cancer risk: an exploratory meta-analysis of observational studies". Nutr Cancer (Meta-Analysis). 63 (5): 663–72. doi:10.1080/01635581.2011.570895. PMID   21667398. S2CID   21567675.
  29. ↑ Lin YW, Hu ZH, Wang X, Mao QQ, Qin J, Zheng XY, Xie LP (February 2014). "Tea consumption and prostate cancer: an updated meta-analysis". World J Surg Oncol (Meta-Analysis). 12: 38. doi: 10.1186/1477-7819-12-38 . PMC   3925323 . PMID   24528523.
  30. ↑ Zheng JS, Yang J, Fu YQ, Huang T, Huang YJ, Li D (January 2013). "Effects of green tea, black tea, and coffee consumption on the risk of esophageal cancer: a systematic review and meta-analysis of observational studies". Nutr Cancer (Systematic Review and Meta-Analysis). 65 (1): 1–16. doi:10.1080/01635581.2013.741762. PMID   23368908. S2CID   8612872.
  31. ↑ Zhou, Hao; Wu, Weiwei; Wang, Fengqin; Qi, Huizhong; Cheng, Zhigang (21 December 2018). "Tea consumption is associated with decreased risk of oral cancer". Medicine. 97 (51): e13611. doi:10.1097/MD.0000000000013611. ISSN   0025-7974. PMC   6320052 . PMID   30572470.
  32. ↑ Zhong, Y; Yang, C; Wang, N; Pan, D; Wang, S; Sun, G (2022). "Hot Tea Drinking and the Risk of Esophageal Cancer: A Systematic Review and Meta-Analysis". Nutrition and Cancer. 74 (7): 2384–2391. doi:10.1080/01635581.2021.2007963. PMID   34818954. S2CID   244682963.
  33. ↑ Shen L, Song LG, Ma H, Jin CN, Wang JA, Xiang MX (August 2012). "Tea consumption and risk of stroke: a dose-response meta-analysis of prospective studies". J Zhejiang Univ Sci B (Review). 13 (8): 652–62. doi:10.1631/jzus.B1201001. PMC   3411099 . PMID   22843186.
  34. ↑ Larsson SC (January 2014). "Coffee, tea, and cocoa and risk of stroke". Stroke (Review). 45 (1): 309–14. doi: 10.1161/STROKEAHA.113.003131 . PMID   24326448.
  35. ↑ Wang, Ze-Mu; Zhou, Bo; Wang, Yong-Sheng; Gong, Qing-Yue; Wang, Qi-Ming; Yan, Jian-Jun; Gao, Wei; Wang, Lian-Sheng (1 March 2011). "Black and green tea consumption and the risk of coronary artery disease: a meta-analysis". The American Journal of Clinical Nutrition. 93 (3): 506–515. doi: 10.3945/ajcn.110.005363 . ISSN   1938-3207. PMID   21248184.
  36. 1 2 Hartley L, Flowers N, Holmes J, Clarke A, Stranges S, Hooper L, Rees K (June 2013). "Green and black tea for the primary prevention of cardiovascular disease" (PDF). Cochrane Database Syst Rev (Systematic Review and Meta-Analysis). 2013 (6): CD009934. doi:10.1002/14651858.CD009934.pub2. PMC   7433290 . PMID   23780706.
  37. ↑ Liu G, Mi XN, Zheng XX, Xu YL, Lu J, Huang XH (October 2014). "Effects of tea intake on blood pressure: a meta-analysis of randomised controlled trials". Br J Nutr (Meta-Analysis). 112 (7): 1043–54. doi: 10.1017/S0007114514001731 . PMID   25137341.
  38. ↑ Chen B, Shi HF, Wu SC (March 2014). "Tea consumption didn't modify the risk of fracture: a dose-response meta-analysis of observational studies". Diagn Pathol. 9: 44. doi: 10.1186/1746-1596-9-44 . PMC   4017777 . PMID   24588938.
  39. 1 2 Jurgens TM, Whelan AM, Killian L, Doucette S, Kirk S, Foy E (2012). "Green tea for weight loss and weight maintenance in overweight or obese adults". Cochrane Database Syst Rev (Systematic review). 2012 (12): CD008650. doi:10.1002/14651858.CD008650.pub2. PMC   8406948 . PMID   23235664.
  40. ↑ Kovacs EM (March 2004). "Effects of green tea on weight maintenance after body-weight loss". British Journal of Nutrition. 91 (3): 431–437. doi: 10.1079/BJN20041061 . PMID   15005829.
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