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SUBJECT: New Year's Resolution: Drink more green tea from Roc Nutrition Investigator

The Fifth International Symposium on Tea and Human Health, supplement to ACJN

Introduction summarizes 11 specific papers - Tea is the most widely consumed beverage in the world after water and is a major source of dietary flavonoids. All tea is derived from Camellia sinensis, an evergreen shrub of the Theaceae family. Postharvest processing of white and green tea leaves includes drying (withering) and rolling (crushing). Further processing by partial or complete fermentation allows polyphenol oxidase to generate high-molecular-weight oligomers and polymers (theaflavins and thearubigins), which result in oolong and black tea, respectively. Whereas tea leaves are composed of an array of compounds, including amino acids, cellulose, lignans, organic acids, mono- and polysaccharides, proteins, and xanthines, the flavonoids and related polyphenols account for ∼35% of their fresh weight. Most of the putative health benefits of tea have been attributed to the flavonoids in tea, although caffeine and L-theanine, a nonproteinic amino acid found only in tea, have also been suggested to contribute to some of these outcomes...There are a great many potential molecular targets for tea polyphenols and their metabolites that are related to the potential cardiovascular, chemopreventive, and neuroprotective effects of tea...Both the polyphenolic components as well as caffeine have been implicated in cancer chemoprevention...Recent meta-analyses of clinical trials suggest that oral administration of tea flavanol-caffeine mixtures increases energy expenditure and fat oxidation and may be associated with modest reductions in BMI...green tea polyphenols enhance osteoblastogenesis and suppress osteoclastogenesis via antiinflammatory and antioxidant pathways and thereby promote greater bone mass and bone strength. ...Green tea polyphenols may favor bone formation, increase muscle strength, and reduce oxidative stress in osteopenic women, particularly when combined with exercise...Observational evidence continues to emerge that tea may act to improve cognitive function, and a recent clinical trial using fMRI shows that green tea increases brain activation in a key area that mediates working memory processing (26). The literature suggesting that tea polyphenols may be useful for the prevention or treatment of various neurodegenerative diseases has also stimulated experimental work in mice, which shows that the tea flavanol (−)-epigallocatechin-3-gallate promotes adult neurogenesis in hippocampal cells in vitro and improves spatial cognition in vivo via sonic hedgehog pathway activation (27). Although tea drinking has long been associated with positive psychological effects on alertness, mood, and stress, until recently few scientific studies have directly addressed these potential benefits. Einöther and Martens (28) review the evidence indicating that tea, through its content of caffeine and L-theanine, can significantly, albeit modestly, affect attention and mood. They note several studies showing a consistent effect of tea on alertness, attention, and arousal, but found little research examining outcomes such as hedonic tone and relaxation. It is worth noting that the psychological benefits of tea and tea ingredients have now been extended to some real-life areas such as driving, creativity, and work performance...Benefits and preventive achtions include include antibacterial and antiviral activity, arthritis, dental caries, type 2 diabetes mellitus, dyslipidemia, impaired immune responsiveness, and neurodegeneration. Despite the promise of this research showing an inverse association between tea and the risk of chronic disease, it is worth emphasizing that tea is also a healthy choice for hydration.

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-Nutrition Investigator, Roc
Professor, Biochemistry, Beloit College
That is our society today. We do not have the time to take care of our beloved ones.  And we do not allow Mother Earth to heal us.  -Thich Nhat Hanh

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