The green tea polyphenol (-)-epicatechin-3-gallate (ECG) may slash the risk of gastric cancer among women by 75 per cent, suggests a new study from Japan
It also highlights the need to consider the sexes separately when undertaking scientific studies in order to identify potentially gender-dependent interactions.Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10 per cent. The four primary polyphenols found in fresh tealeaves are epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC).The new study, which used a case-control design, matched 494 people with gastric cancer (cases) with 494 healthy people (controls). Blood samples were taken and polyphenol levels measured using high-performance liquid chromatography (HPLC).Sasazuki and co-workers report that blood levels of ECG between 0.32 and 9.2 ng/mL were not associated with any change in gastric cancer risk among women. However, blood levels of 9.3 ng/mL were associated with a 75 per cent reduction in risk in women, compared to women with blood levels below the detectable limit.On the other hand, "for men, a high plasma level of (-)-epigallocatechin was associated with an increased risk of gastric cancer," said the researchers.
It also highlights the need to consider the sexes separately when undertaking scientific studies in order to identify potentially gender-dependent interactions.Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10 per cent. The four primary polyphenols found in fresh tealeaves are epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC).The new study, which used a case-control design, matched 494 people with gastric cancer (cases) with 494 healthy people (controls). Blood samples were taken and polyphenol levels measured using high-performance liquid chromatography (HPLC).Sasazuki and co-workers report that blood levels of ECG between 0.32 and 9.2 ng/mL were not associated with any change in gastric cancer risk among women. However, blood levels of 9.3 ng/mL were associated with a 75 per cent reduction in risk in women, compared to women with blood levels below the detectable limit.On the other hand, "for men, a high plasma level of (-)-epigallocatechin was associated with an increased risk of gastric cancer," said the researchers.
