Functional benefits

For centuries, there have been many records in China relating to the health benefits of drinking tea. People have believed that tea can stimulate thought processes and mental alertness increase blood flow clear the urine and facilitate its flow prevent tooth decay increase the body s power of resistance to a wide range of diseases and prolong life expectancy. However, these claims were primarily anecdotal. It is only in the last few decades that the health benefits of tea are beginning to be demonstrated from a scientific perspective. Numerous recent reports on tea and human health have been examined and this chapter gives a brief review of certain aspects of current research. 

Cancer is a major cause of premature death in modern society. In vitro and animal research indicates that tea, mainly green tea, may be effective against a wide variety of cancers. Activity has been observed in vitro at all three levels of cancer progression, namely initiation, promotion and transformation (Mitscher et al, 1997). 

Tea extracts have been demonstrated to inhibit a wide range of inflammatory responses and may be useful in treating chronic inflammatory states. For example, rheumatoid arthritis is an inflammatory disease that causes pain, swelling, stiffness and loss of function in the joints. The antioxidants in green tea may prevent or reduce the severity of these symptoms by reducing inflammation and slowing cartilage breakdown (Adcocks et al, 2002 Haqqi et al, 1999). 

Diabetic patients have reduced antioxidant defences and suffer from an increased risk of free radical-mediated diseases such as coronary heart disease. EC has a pronounced insulin-like effect on erythrocyte membrane-bound acetylcholinesterase in type II diabetic patients (Rizvi and Zaid, 2001). Tea polyphenols were shown to possess anti-diabetic activity and to be effective both in the prevention and treatment of diabetes (Choi et al, 1998 Yang et al, 1999). The main mechanism by which tea polyphenols appear to lower serum glucose levels is via the inhibition of the activity of the starch digesting enzyme, amylase. Tea inhibits both salivary and intestinal amylase, so that starch is broken down more slowly and the rise in serum glucose is thus reduced. In addition, tea may affect the intestinal absorption of glucose. 

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Acute Anticoagulation for AF-associated Stroke HAEST and 1ST provided valuable data on relatively large numbers (449 in HAEST, 3169 in 1ST) of patients with AF-associated ischemic stroke treated with acute anticoagulation (danaparoid in HAEST, UFH in 1ST). HAEST found no reduction in early stroke recurrence or effect on late functional outcome in the LMWH arm. In contrast, 1ST found a dose-dependent reduction in early recurrence rates, but no late functional benefit associated with UFH. However, this was offset by an increase in rates of sICH among patients with AF receiving UFH, with no net benefit in the composite outcome of recurrence stroke and sICH combined. The reasons for the discrepancy between trials is unclear. 

Functional benefits of carotenoids vision, cancer and cardiovascular disease... 

All the actual or putative functional benefits of carotenoids are dependent on their bioavailability amounts consumed, amounts released from the food structure during digestion and extent of absorption and tissue distribution. The following three sections deal with each of these issues in turn. 

The functional benefits of fiavonoids the case of tea 139 8.4.1 Relative activity of tea catechins... 

Functional benefits liver, gastrointestinal and colonic health... 

Some of the newest and most exciting developments in functional foods are products that claim to influence mood and enhance both mental and physical performance. This important collection reviews the range of ingredients used in these performance functional foods, their effects and the evidence supporting their functional benefits. 

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