Green tea is made by the rapid steaming of freshly harvested leaves which stops the process of oxidation to black tea.
Green and black tea contain similar levels of total flavonoids but the difference in oxidation means there are differing types of flavanoids. Black tea has higher levels of theaflavins and thearubigins and green tea has 3.5 x the catechins levels. The main catechin in green tea is Epigallocatchin-3-gallate (EPCG).
Brewing time, the method to make your tea and the tea quality are all things that influence antioxidant status. Tea polyphenols are effective antioxidants and scavengers of free radicals. Studies show an increases in antioxidant levels in humans after drinking green tea. This is what is likely to provide any health benefits.
There is a misconception that green tea is caffeine free like a herbal tea. It is lower in caffeine but still contains some. Up to 400mg of caffeine a day is considered safe. That’s 8 cups of green tea! It may not be as hydrating as water but it does still provide hydration.
Black Tea : 40-70mg caffeine per cupCoffee: 80-115mg caffeine per cupGreen Tea: 25mg caffine per cup
Most studies on tea are observational, are conducted on animals or in Asia where there is a different diet. Therefore it is an area we need clearer studies and research results.
Heart disease
Flavanoids in green tea has been shown to lower LDL cholesterol levels and decrease blood clotting. A meta-analysis of 13 research trials showed a decrease in systolic and diastolic blood pressure, total and LDL cholesterol, blood Triglyceride (fat) levels and overall stroke risks. So it does sound like there are benefits for your heart.
Weight loss
This is a an area that had a lot of interest. There is some mixed evidence here suggested green tea may stimulate thermogenesis and increase fat oxidation. This means you burn more calories when you digest your food and you use up more fat stores. Sounds good but the results were modest and so this won’t give you large weight loss. It’s certainly no magic cure but switching from a soft drink to green tea daily will reduce your calorie intake.
Cancer
There are very mixed results in the research so over there is no clear proof either way. Green tea is certainly packed with antioxidants so it could help and it won’t hinder.
Osteoporosis
Animal studies and studies on post menopausal women shows an association between tea consumption and better bone health due to the tea polyphenols. We have some emerging evidence for green tea improving muscle strength and bone health. An exciting area to focus on.
Brain Health
There is some research showing a link between green tea and brain health with it improving memory and brain power. Could be worth a green tea cuppa in the mornings.
Over all we need more studies to give us further information but it does seem that green tea is a good choice for your cuppa.
