Black tea consumption

Duffy SJ, Keaney JF Jr, Holbrook M, Gokce N, Swerdloff PL, Frei B and Vita JA. 2001. Short- and longterm black tea consumption reverses endothelial dysfunction in patients with coronary artery disease. Circulation 104(2) 151-156. 

Clifford, M.N., Copeland, E.L., Bloxsidge, J.P., and Mitchell, L.A., Hippuric acid is a major excretion product associated with black tea consumption, Xenobiotica, 30, 317, 2000. 

Widlansky, M.E., Duffy, S.J., Hamburg, N.M., Gokce, N., Warden, B.A., Wiseman, S., Keaney, J.F., Jr., Frei, B., and Vita, J.A., Effects of black tea consumption on plasma catechins and markers of oxidative stress and inflammation in patients with coronary artery disease. Free Radical Biol Med, 38, 499, 2005. 

McAnlis, G.T., McEneny, J., Pearce, J., and Young, I.S., Black tea consumption does not protect low density lipoprotein from oxidative modification, Eur. J. Clin. Nutr., 52, 202, 1998. 

Davies MJ, Judd JT, Baer DJ, Clevidence BA, Paul DR, Edwards AJ, Wiseman SA, Muesing RA, Chen SC. 2003. Black tea consumption reduces total and ldl cholesterol in mildly hypercholesterolemic adults. J Nutr 133 3298S-3302. 

India is the largest black tea consumer. Moreover, India is the largest black tea producer by 919.4 thousand tons, contributing 37.44% to world production in 2005. Almost 85% of total Indian households drink tea. In 2005, 694.5 thousand tons of black tea was consumed, which accounted for 29.65% of world black tea consumption (table 1.4) and 74.84% of its own tea production (928.0 thousand tons). India s per capita annual tea consumption has increased from 0.61 kg in 1991 to 0.64 kg in 1998, and to an estimated 0.69 kg in 2005. Unlike the international market, where iced tea is prevalent, tea in India is generally consumed as a hot beverage infused either separately or as a mixture of milk and sugar. CTC is generally preferred all over India. 

Van Dorsten, F. A., Daykin, C. A., Mulder, T. R, and Van Duynhoven, J. R. 2006. Meta-bonomics approach to determine metabolic differences between green tea and black tea consumption. J. Agric. Food Chem. 54 6929-38. 

Hippuric acid was identified as a major metabolite associated with black tea consumption. " The compound l,3-dihydroxyphenyl-2-0-sulfate (sulfate conjugate of pyrogallol) was also identified as a black tea metabolite in humans. " Very low levels of theaflavins in plasma and urine were reported in humans after consumption of black tea. It was reported that the ingestion of either green tea or black tea results in a major increase in the excretion of hippuric acid into urine. The authors concluded that green tea and black tea consumption result in similar amounts of microbial degradation products that are absorbed by the body. They speculated that these microbial metabolites, not the native tea flavonoids, may be responsible for at least some of the health effects attributed to tea consumption. ... 

In one study (Goldbohm et al., 1996), an association was songht between black tea consumption and the snbseqnent risk of stomach, colorectal, Inng, and breast cancers in The Netherlands Cohort Stndy on Diet and Cancer among 58,279 men and 62,573 women aged 55 to 69 years. The consnmption of tea showed an inverse association with... 

An association between black tea consumption and the subsequent risk of colorectal cancer was sought in The Netherlands Cohort Study on Diet and Cancer (Goldbohm et al., 1996). No association was observed between tea consumption and risk of colorectal cancer The risk among tea drinkers in each consumption category was similar to that among nondrinkers. The authors concluded that this study did not support the hypothesis that consumption of black tea protects against fom of the major cancers in humans, and there was no evidence that black tea has a cancer-enhancing effect. 

Black tea consumption may reduce absorption of iron, calcium, and magnesium (Disler et al. 1975 Gardner et al. 2007 Merhav et al. 1985). 

Figure 2 Heat map representing the total urinary output of 10 selected NMR variables/ metabolites measured in 20 subjects after black tea consumption. The dark grey and light grey cells indicate high and low urinary output levels.

Glucuronides Sulfates Mainly mixed conjugates Glucuronide 5-position Glucuronide sulfate Mixed conjugates Glucuronide 5-position Mainly glucuronide Not detected except after black tea consumption Mainly sulfate... 

Urinary excretion 3-10% of dose 5-7% of dose 2-4% of dose Not detected except after black tea consumption Not detected except after black tea consumption... 

Flavanols have also been measmed in plasma after green and black tea consumption by using colorimetric detection after extraction and complexation with 4-dimethylaminocinnamaldehyde (DMACA) [101]. This method is specific for flavanols, but it is unknown whether there are interferences in biological samples. Additionally, the reaction does not occur if the A-ring is conjugated... 

He YH, Kies C. Green and black tea consumption by humans impact on polyphenol concentrations in feces, blood and urine. Plant Foods Hum Nutr 1994 46(3) 221-229. 

Dora, I., Arab, L., Martinchik, A., et al. 2003. Black tea consumption and risk of rectal cancer in Moscow population . Annals of Epidemiology., 73 405-411. 

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