'Must know' tips to getting the best from your teas!
What’s the difference?
Well it’s all in the processing. White tea is the young tea leaves (Camellia sinensis) which are picked prior to them opening fully (in the bud stage). The name ‘white tea’ comes from the small white filaments that cover the unopened tea leaves.
Green tea is leaves picked after opening. Though a little older, they are still fresh leaves which are then fermented slightly (dried) and made ready for use. Black tea is the green tea leaves that are fermented and dried (oxidised), turning them black in colour. Black tea is somewhat more processed than green tea and the oxidation it undergoes in processing increases its shelf life, accounts for its flavour and colour, the process also alters some of the catechins in the leaves to give rise to other antioxidants (theaflavins and thearubigens).
The lesser processing of white and green tea tends to leave intact more compounds which give health benefits. It may be possible that white tea has a slightly higher level of antioxidants, though this is not yet entirely clear. In Japan, green tea forms part of the age old Tea Ceremony.
What’s the good stuff in green tea?
Green tea contains a group of antioxidants called polyphenols (also in red wine). You know that drying effect red wine and green tea have on your mouth? Well that’s the polyphenols - they have an astringent effect. The theory is that this helps plants to defend themselves from insects.
Green tea contains polyphenols such as catechin, epicatechin, epicatechin gallae and more that are reputed to be involved in inhibiting mutation of cells that lead to cancer, as well as preventing nitrosamine formation. GT’s main active ingredient is thought to be epigallocatechin gallate (EGCG) as well as similar derivatives that are believed to target digestive tract organs, the liver and the lungs. EGCG may inhibit tumour growth by inhibiting kinases that tumours need, as well as being antioxidant by working on the glutathione detox phases. Lastly, GT has been found to inhibit our production of nitroso free radical compounds in the body.
While we’re talking antioxidants, you’ve likely heard of bioflavonoids (sometimes referred to as vitamin P). Bioflavonoids are a group of antioxidant compounds that appear to prevent free radical damage in the body, they can inhibit cancer cells and possibly slow ageing (yeah). One of the top bioflavonoids found in tea are catechins, and yes also in red wine, I hear a few of you cheering out there. Green tea catechins appear to have a positive effect on body weight by reducing body fat levels. It’s thought GT does this via improving metabolic rate, increasing energy expenditure and promoting fat oxidation. This is further enhanced by the caffeine which increases sympathetic nervous system activity. Other theories include the up-regulation of enzymes in fat oxidation in the liver and appetite control (Rains et al,. 2011). Studies also support GT’s effect on blood glucose and positive outcomes in relation to type 2 diabetes via reduced fasting insulin levels (Liu et al., 2013; Zhen et al., 2013). Some studies have shown reduced risk of cancers such as digestive system cancers, including stomach cancer (in women), though others haven’t found the same for cancers such as oesophagus (Gao et al., 2013).
You might also see green tea extracts (GTE), a supplemental form of green tea, they are reported to reduce the risk of cardiovascular disease and stroke but not coronary heart disease (Kokubo et al., 2013). Potentially, the effect is in part due to the cholesterol lowering effect, specifically LDL lowering (with no significant effect on HDL or TG levels)(Kim et al,. 2011).
Does green tea have more caffeine?
If you consider the starting product is the same, the actual caffeine differences is quite small. In fact, due to the processing black tea simply has a higher range of potential caffeine content, both can have up to 50mg per cup of tea. so it's good to keep in mind that green tea is a herbal tea given it comes from a plant, but it differs from most herbal teas in its caffeine-containing characteristic.
Maybe not an ideal bedtime cuppa given the caffeine ;-)
How much is enough?
One cup of green tea is thought to have anywhere between 150-400mg of polyphenols. That’s a pretty wide range - most recommendations suggest one to two small – medium cups a day is enough. 1 cup of tea yields around 200mg of EGCG catechins. But… if you add a little lemon (vitamin C) the effect has been reported to be up to 80% better. Vitamin C may increase the absorption of catechins by 13 times. Some 80% of catechins are preserved after digestion by adding vitamin C or vitamin C-containing liquid or powder.
What’s the take home?
As we pretty much tend to say, enjoy as part of a varied, wholefood diet. Enjoy a lovely tea with friends and family, relax, breath, be in the moment. Perhaps the Green Zone within the Blue Zone? Increasingly we are becoming ‘commonsensalists’ here at Cadence Health. It’s so cool to be able to get jiggy with the technical details of foods and compounds and health, but it can be like standing in nose to nose with a beautiful painting and expecting to appreciate the intention of the artist. Step back, see the big picture and savour it.
We all have a role to play in community health, the only question is how do we play this role? Through intelligent, evidence-based inquiry we can understand how to health coach to support others in taking on positive behaviour change.