Population based, green tea is the most popular beverage world-wide, and with good reason. I have written before on the benefits of the calming amino acid theanine and the health benefits of the plant chemical EGCG (epigallocatechin gallate) that is present in high amounts of matcha tea, and now there is another study showing the benefits of yet another compound in green tea, this time in prostate cancer.
In this study, Philadelphia-based researchers tested a trademarked extract from green tea called Polyphenon E.
They were looking for a number of biomarkers – molecules – including vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) which are indicators of developing cancer.
They also looked for prostate specific antigen (PSA) – a protein only found in the prostate. Levels can rise if cancer is present.
‘12 cups’
The study included 26 men, aged 41 to 72 years, who had been diagnosed with prostate cancer and who were scheduled for radical prostate surgery.
Patients took four capsules containing Polyphenon E for an average of 34 days, up until the day before surgery – the equivalent of around 12 cups of normally brewed concentrated green tea.
The study found a significant reduction in levels of HGF, VEGF and PSA, with some patients demonstrating reductions of more than 30%.
Most anti-cancer research in green tea has focused on the EGCG compound, and the trademarked extract Polyphenon E seems to be important as well (likely has EGCG as a component). The advantage of taking the beverage over the capsule is that you do not need a capsule for each green tea compound, you get the whole food. And in this case with prostate cancer, a respectable 12 cups is not difficult once you acquire a taste for this beverage.
I still prefer matcha for its higher content of EGCG and of theanine, though it is higher in caffeine as well, which can be troublesome for some caffeine sensitive patients.
What’s the other evidence on green tea?
- Genital Warts: a green tea ointment was able to clear warts in 24-60% of patients after 16 weeks treatment
- Reduced cancer risk: increased consumption is associated with reduced bladder, esophageal, stomach, and pancreatic cancer
- Reduced cholesterol: another compound called theaflavin (also present in black tea) reduced cholesterol. Population based data indicates that higher consumption of green tea is associated with lower cholesterol as well.
- Low blood pressure: consumption reduces postural associated symptoms. Unfortunately, nothing special related to green tea here. It seems to be the caffeine that is helpful.
- Reduces risk of Parkinson’s: again an association between increased green tea consumption and decreased or delayed Parkinson’s disease. In men the effect of the tea was more pronounced at more cups (5 to 30) cups, and in females increasing doses did not seem to be related to the protective effect.
- Diabetes risk reduction: adults who drank 6 or more cups had roughly a third less risk. Again this is an association, so it might be that those who are prone to drinking green tea tend to have healthier diet and lifestyles than those who don’t. However, there is sufficient biochemical reason as to why green tea probably exerts a separate medicinal effect.
