Polyphenols Flavonoids, Theaflavins and Thearubigins
The indisputable health benefits of green tea are well documented; its superior nutritional, healing and preventive qualities has earned green tea a well deserved place in the super-food hall of fame. What you may not be aware of though, is that black tea ,while officially ranked lower down the scale in terms of the health benefits it offers, brings many antioxidant perks of its own.
This is hardly surprising when you consider that both black and green along with other tea varieties such as white, oolong and pu-erh all originate from the same source, namely the “Camellia sinensis” plant. It is this factor which distinguishes true teas from their herbal and fruit counterparts, which technically are not teas at all but belong to a category known as “Tisanes.”.
The fact that black tea packs its own healthy punch is good news for those who prefer a more full bodied experience in contrast to the lighter more delicate taste of green tea.
What are the differences between Green and Black Tea?
The distinction between tea varieties is down to their divergent processing techniques, the first stage known as withering applies to all types of tea production, and consists of laying the freshly picked tea leaves out in direct sunlight in order to remove some of the moisture.
For green tea the second stage involves either gently steaming or pan frying) the withered leaves in a wok; while steaming is usually done by Japanese tea manufacturers, pan frying is more common in China.
Regardless of which method is used, both streaming and pan frying causes denaturing of the plant enzymes thus preventing oxidation of the polyphenols and hence preserving the tea’s ‘characteristic green color.. This minimal processing also results in green tea retaining most of its nutritional properties, however it also has the shortest shelf life of any kind of tea.
In contrast, black tea like other remaining tea types is not denatured, thus the enzymes are allowed to react with oxygen in the air causing the plant to oxidize. In addition, chlorophyll in the leaves are broken down by enzymes which has the effect of releasing or transforming the plant’s polyphenols and flavonoids
As we are focusing on black tea here, a detailed discussion regarding other types of fermented teas is out of the scope of this article. Suffice to say it is the differing lengths and degrees of the fermentation process that gives each fermented tea its own unique qualities and characteristics.
Health benefits of Black Tea
Black tea has a lot of caffeine (a known dehydrator), hence some dispute its value as a substitute hydra-tor for pure water. Despite these concerns be assured the body will always maintain a net amount of water from drinking black tea,
Due to its caffeine content drinking a moderate amount of tea e.g 3-4 cups per day can slightly raise blood pressure, however this effect does not last for long, neither is it associated with any long term high blood pressure issues.
As with other varieties of tea there are decaffeinated versions of black tea, however studies have suggested that while the process of decaffeinating tea is no cause for health concerns, it does reduce the amount of beneficial flavonoids present.
In Jennifer Warner's article for WebMD “Drinking Black Tea may soothe Stress” Andrew Steptoe a researcher at the University College of London is quoted as saying “Although it does not appear to reduce the actual levels of stress we experience, tea does seem to have a greater effect in bringing stress hormone levels back to normal," This was Steptoe’s conclusion to a research project he had participated in concerning the positive effects that drinking tea has on stress.
Black tea derives its power from the transformation of the antioxidant epigallocatechin gallate (EGCg) into other useful substances; during the fermentation process; the EGCg is converted into compounds known as theaflavins and thearubigins . In recent studies theaflavins have been found to lower bad (LDL) cholesterol, theaflavins are also the catalyst of the unique color and flavor of black and other fermented teas.
In their publication Thearubigins rich Black Tea Fraction reveals strong Antioxidant Activity, Sangeeta Kumari Sinina and Saroj S. Ghaskadbi conclude “TR rich fraction has good antioxidant properties, which correlate to the total phenolics and flavonoids content and provide significant protection against oxidative damage to biomolecules (lipids, proteins and DNA) in rat liver mitochondria”.
Clive Swift documents several key several key benefits related to black tea in his paper “Strange and awesome benefits of Black Tea” as follows:
- Fresh breath and improved Oral Health
The power of those black tea antioxidants are far reaching, not only do they zap free radicals in the body they also contain anti plaque properties. As well as creating bad breath, plaque is also responsible for gum disease which ultimately leads to tooth loss. Drinking tea daily will help reduce the plaque buildup on your teeth. and help you to keep a healthy mouth, and all your teeth.
- Reduced risk of Stroke and Heart Disease
As jobs become more demanding and stress rockets to unprecedented highs, heart and stroke victims are an increasing cause for concern. Research findings punished by J. Zhejiang “Green and Black Tea consumption and risk of stroke, a meta analysis” brought the following conclusion:
“Tea consumption is associated with reduced risk of stroke, particularly ischemic stroke. More well designed rigorously conducted studies are needed in order to make confident conclusions about the association between tea consumption and stroke sub-types”
- Reduced risk of Diabetes
With all the hidden sugar additives that manufacturers sneak into our food, its tough to discern what is healthy and what is not these days, especially with controversial labeling and marketing ploys that imply a product is healthy when it is not. The results of this are all too clear and present with the rising number of diabetic cases, (especially type 2) in the western hemisphere.
One piece of good news here though is that studies carried out by researchers like Yonsei, Med J,”Long term tea consumption is prevalent with reduced type 2 diabetes...” suggest that there is an apparent correlation between long term tea consumption and a reduced prevalence of type 2 diabetes.
Although much more research is needed on black tea and its benefits, early results are positive and encouraging. In part two of this series on black tea we look at ways of maximizing the nutritional integrity of our tea through the avoidance of certain post additives.