Issue link: http://read.dmtmag.com/i/716988
62 STiR coffee and tea / Issue 4, 2016 (August/September) Bond also explained that the benefits of tea drinking are further extended to women, as shown in a ten-year Australian study involving 1,188 women. The consumption of three or more cups of tea a day was associated with a statistically significant 30% decrease in the risk of osteoporotic fractures and, says Bond, "It is thought that the flavonoids found in tea may have contribut- ed to these benefits. And data from 14 studies and 9,958 cases of hip fracture also found that the risk of hip fracture was 16% lower among the highest ver- sus the lowest consumers of tea. Compared with no tea consumption, drink- ing one to four cups of tea per day reduced the risk of hip fracture by 28%. Green tea also has a beneficial effect on teeth. As Bond explained, "a new lab study looked at the effects of green tea on tooth dentine, the second layer of the tooth that can become eroded. After dentin samples had been sub- mersed in green tea solution for up to three days, it was found that this helped to reduce the wear and roughness caused by dentine erosion. And other work with green tea showed that green tea extracts have benefits in terms of lower- ing numbers of oral cariogenic bacteria." Other studies show other benefits and found that within just 30 minutes to one hour of drinking green tea, the brain waves increased, indicating that the green tea seems to have an impor- tant effect on cognitive function. Tea and hydration The UK Government's Eatwell Guide recently stated that individuals should aim to drink 6 to 8 glasses of fluid every day and said that could include water, tea, lower-fat milk, and sugar-free drinks. A study sponsored by the Tea Ad- visory Panel's study aimed to ascertain whether tea is as effective a hydrator as water. Many people believe that, because of its caffeine content, tea acts as a diuretic and therefore reduces the hydrating effects of the beverage. Bond ex- plains that a study of this type must be carried out on a group of healthy indi- viduals and that parameters for research are set by the European Food Safety Authority. "Today's studies are not just about the antioxidant effects of tea on human health but on the mechanisms of absorption of those antioxidants and their effects on different functions in the body. A number of studies into green tea were carried out in the 1990s but now there are more research pro- grams looking at black tea. Green tea is easier to study because catechins such as EGCg (epigallocatechin gallate), can be easily tracked in the blood. "During the oxidation of black tea, EGCg is converted to thearubigins and theaflavins which are more soluble and disappear easily into the system, making them much harder to track as they pass through the body. It's there- fore much harder to assess the effects." In order to measure tea's effects on hydration in the body, a group of 21 healthy, resting men between the ages of 20 and 55 were given four mugs of 240ml servings of black tea over a 24- hour period, and four mugs of 240ml of water over a second 24-hour period. Samples of urine were measured for creatinine concentration, osmolality, and the concentration of certain electrolytes. Blood samples were measured for levels of electrolytes, protein concentration, urea, creatinine and osmolality, and after analysis of the measurements, tea was found to have the same hy- drating properties as water. L-theanine research Bond and the Tea Advisory Panel's work have also been involved in research into L-theanine but few tea companies have used information about L-the- anine as a marketing tool since a 2011 report from the EFSA said that more research was needed before claims can be made about the calming benefits of this amino-acid that only exists in the Bay Bolete mushroom, Ilex Guayusa, an Amazonian tree related to the holly, and Camellia sinensis. AVT tea laboratory Headquarters AVT Tea Services Tea flavonoids The regular newsletter, published by Bond with his TAP colleague Dr. Carrie Ruxton as part of their role to provide the public with independent information about tea, wrote a few weeks ago, "A recent article in the American Journal of Nutrition found that drinking just two cups of tea daily was associated with a 40% reduced risk of mortality." Ruxton responded, "This is not particularly sur- prising given that tea is a major source of flavo- noid compounds ….. of particular note, a higher flavonoid intake of around 350 mg, equivalent to approximately two cups of tea, was associated with a 40-50% reduced risk of cardiovascular dis- ease and cancer mortality compared with those with the lowest intake." And Bond's overall mes- sage is that "Data pooled from one recent large study, consisting of 22 studies, found that regu- lar tea consumption reduces the risk of coronary heart disease by 27% and that drinking three cups of black tea a day produces significant reduction in unhealthy low-density lipoprotein (LDL) cho- lesterol, both systolic and diastolic blood pressure, and reduces the risk of suffering a stroke, or dying from stroke, by 21%."