Many previous epidemiological studies have revealed that green tea or green tea catechins contributed to the preveintion of
lifestyle-related diseases. Several cohort studies on the relationship between green tea consumption and cardiovascular disease (CVD)
risk/type 2 diabetes mellitus risk have been conducted. The results showed that green tea consumption (5 or more cups/day) was inversely
associated with mortality from CVD and all causes. Within CVD mortality, the strongest inverse association was observed for
stroke mortality. Furthermore, consumption of green tea, coffee, and total caffeine was associated with a reduced risk for type 2 diabetes.
On the other hand, the analysis of randomized clinical trial (RCT) studies showed that the administration of green tea beverages or extracts
resulted in significant reductions in serum total cholesterol and LDL-cholesterol concentrations, but had no apparent effect on
HDL-cholesterol. Green tea reduced fasting blood glucose levels in a small intervention trial, although no improvements in HbA1c levels
were seen. Continuous intake of green tea containing catechins and caffeine (5 or more cups per day) may be beneficial for body weight
management, vascular disease risk reduction via LDL-cholesterol improvement, and type 2 diabetes risk reduction through the lowering
of fasting blood glucose levels.
Epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3”Me) isolated from cv. “Benifuuki” green tea has been shown to strongly inhibit
mast cell activation and histamine release after FcepsilonRI cross-linking through the suppression of tyrosine phosphorylation (Lyn) of
cellular protein kinase, and the suppression of myosin light chain phosphorylation and high-affinity IgE receptor expression via the binding
to 67 kDa laminin receptors. A double-blind clinical study on subjects with Japanese cedar pollinosis was carried out. At the eleventh
week after starting intake, which was coincident with the most severe period of cedar pollen-scattering, symptoms such as nose blowing
and eye itching were significantly relieved in the Benifuuki group compared with the placebo group. Six weeks of intake of Benifuuki
green tea containing O-methylated catechins was useful for reducing some of the symptoms derived from Japanese cedar pollinosis, and
did not affect any of the normal immune responses in the subjects with Japanese cedar pollinosis. Based on an investigation into the effects
of the cultivars, tea seasons of crops and manufacturing methods, it was concluded that green or semi-fermented tea made from
fully-matured Benifuuki in the second crop season should be consumed.