Plant Species: Camellia sinensis
• Camellia sinensis is a small evergreen shrub with white flowers, native to the mountainous regions of China, Japan and India.
• Whether black, green or white tea, they all come from the same plant. The way the plant is dried is what differentiates them.
• To make black tea, the leaves are withered, rolled and slightly heated. They are then fermented before the final heating/drying process.
• Much to the surprise of adamant green tea drinkers, black tea too is teeming with nutrients. By consuming it with additives like milk or sugar, some of the health benefits are depleted, but not entirely lost.
History and Cultural Significance:
• Tea is believed to have originated with the Buddha. The story goes that while meditating, Buddha fell asleep and upon awakening, he cut his eyelids off in disgust. Tea plants grew from where his eyelashes landed, so that he could give the gift of awareness to his disciples.
• Tea is used extensively in the traditional medicine systems of China, Hong Kong, Japan & Korea.
• In China, drinking tea dates back to 2700 BCE.
• Practitioners of Traditional Chinese Medicine (TCM) began using tea for the prevention of disease between 1100 BCE and 200 BCE and continues today.
• It was not until the T’ang dynasty (618-907 BCE) that tea became popular and the Chinese tea trade flourished.
• Traditionally, tea was rarely used as a medicine, except as a stimulant, astringent (drying agent) & to relieve headaches.
Tea Sales Facts
• After water, tea (i.e., beverages from the tea plant, Camellia sinensis, is the second-most consumed beverage worldwide.1
• On any given day, more than an estimated 50% of Americans drink tea (including iced). On a regional basis, the South and Northeast have the greatest concentration of tea drinkers.1
• Approximately 85% of tea consumed in America is iced. From 2002 to 2012, the ready-to-drink tea sector grew more than 15-fold.
• Instant tea is declining and loose tea is gaining in popularity, especially in specialty tea and coffee outlets.
• In 2012, Americans consumed well over 79 billion servings of tea — more than 3.6 billion gallons. About 84% of all tea consumed was black tea, 15% was green tea, with the remainder comprising oolong and white tea.2
Tea Facts: Did You Know?
• Whether black, green, white or oolong tea, they all come from the same plant, Camellia sinensis. The difference lies in the processing of the leaves, generally two leaves plus one bud.
• Tea processing is the most important quantifier when determining or producing a tea type: Green tea, yellow tea, white tea, oolong tea, black tea and post-fermented teas all begin as fresh camellia sinensis leaves and go through different processing steps. While there are an infinite number of variations that result in an infinite number of tea styles, the same underlying processing methodologies largely define the tea’s type.
• Black tea is most widely consumed in North America, Europe and Western Asia and accounts for 78% of the worldwide tea production (WTP). Green tea is mostly consumed in Japan and parts of China, and accounts for 20% of the WTP. Oolong tea is popular in Taiwan and southeastern China and accounts for only 2% of the WTP.
• The name "white tea" derives from the fine silvery-white hairs on the unopened buds of the tea plant, which gives the plant a whitish appearance. The beverage itself is not white or colourless but pale yellow.
• Although there are many different kinds of antioxidants, they all do something in common: they protect the DNA in our healthy cells from damage caused by free radicals, which come from harmful chemicals that we absorb from things like cigarette smoke, pollution, fried foods, and other environmental sources. Too many free radicals running around the body can cause mutations in DNA that can lead to cancer.
• Without researching the issue, one might assume that green tea has much more of an antioxidant punch than black tea, since it is less “processed” than black tea. Surprisingly, it is not true.
• The fermentation and other processes involved in creating black tea certainly alter the main antioxidant type found in the relatively unprocessed green tea, called “catechins”. There are at least 4 types of catechins in green tea. As they are oxidized and dimerized (two molecules joined together to form a molecule where one half is exactly identical to the other half) they change form and become theaflavin, another antioxidant.
• Like the catechins, the theaflavins of black tea, in all their various forms, have been shown to “possess the same antioxidant potency as catechins present in green tea”. 4
• Importantly, the conversion of catechins to theaflavins during fermentation in the production of black tea “does not alter significantly their free radical scavenging activity.”4 Being potent is one thing, but being prone to scavenge for free radicals to eliminate is of the utmost importance in preventing or battling disease.
• Black tea’s polysaccharides also showed the highest scavenging effect on free radicals, compared to the other teas.12
A Better Heart
• Theaflavins are produced during the fermentation process in the making of black tea. There is epidemiological evidence and clinical trials which support the use of theaflavins in reducing cardiovascular disease risk factors and mortality. They appear to accomplish this by elevating total and low-density lipoprotein (LDL)-cholesterol and oxidation of cholesterol. Both are involved in the development of atherosclerosis (a disease of the arteries characterized by the deposition of plaques of fatty material on their inner walls).3
• Two long-term Dutch studies concluded that men and women who consumed as little as 3 cups per day of black tea (~ 13 oz.) reduced myocardial infarction (heart attack) risk by 68% compared to non-tea drinkers.3
• Drinking more than 4.7 cups per day (~20oz) of black tea cut the risk of stroke in men by 31% compared to men who drank less than 2.6 cups per day (~11oz)3
• A 2014 review and meta-analysis of randomized controlled trials concluded that regular consumption of black tea can reduce blood pressure. Although the effect is small, it is none-the-less significant and “could be important for cardiovascular health at population level”.7
• Tea has attracted considerable attention for its cardio-protective effects. The polyphenols in tea have been shown to have a beneficial effect by reducing arterial stiffness (AS). Why is AS significant? AS (arterial wall thickening & loss of elasticity) is a predictor of total mortality and future cardiovascular disease, such as heart attack, stroke and heart failure.9
Cancer & Black Tea
• In a 1998 study, exposing human stomach cancer (KATO III cells) to black tea theaflavin extract, led to the inhibition of cancer growth and to cancer cell apoptosis (A form of cell death in which a programmed sequence of events leads to the elimination of cells without releasing harmful substances).5
• Black tea is a significant source of dietary flavonols (type of antioxidant), accounting for about 30% of the dry weight of tea leaves. A meta-analysis covering 12 studies and involving 9,513 cases and another 181,906 women as controls, concluded that an intake of flavonols is associated with a significantly reduced risk of breast cancer in post-menopausal women, but not in pre-menopausal women.
• In animal tumour studies there is abundant experimental and epidemiological evidence accumulated in the past decade from several centers worldwide that polyphenols (antioxidants) from black and green tea can afford protection against chemically-induced cancers that involve the lung, stomach, esophagus, duodenum, pancreas, liver, breast, colon and skin. The first large human studies are underway at the MD Anderson Cancer Centre with green tea and patients with tumours.
• In a 2006 study, black tea extracts were found to be an effective treatment for patients suffering from damaged skin following radiation treatment for cancer. The polyphenols with their anti-inflammatory properties were thought to be the reason. If so, then we would expect green tea to be even more effective, as green tea has more potent anti-inflammatory effects than black tea.10
• Polyphenols – antioxidant compounds abundantly present in black tea and red grapes appear to improve the ecosystem (intestinal flora) of the human gastrointestinal tract. Using an in vitro (taking place in a test tube, culture dish, or elsewhere outside a living organism) model of the gut ecosystem, researchers from the Netherlands showed that black tea polyphenols stimulated the growth of Klebsiella, Enterococcus and Akkermansia microbes, all healthy intestinal flora, while red grapes stimulated 3 additional healthy microbes.17
• Epidemiological evidence points to a supportive role of tannins found in black tea in preventing osteoporosis (a condition in which the bones become brittle and fragile from loss of tissue, typically as a result of hormonal changes, or deficiency of calcium or vitamin D).
• A study of 1256 women, ages 65-76 in the U.K. concluded that “tea drinkers had significantly greater bone mineral density measurements than non-tea drinkers.3
Helps Oral Health
• Published in the US National Library of Medicine Institutes of Health, a 2009 abstract states that polyphenols from cocoa, coffee and tea have cariogenic [(a substance or action that interferes with the development of dental caries (tooth decay)]. Phew. What a relief!! They accomplish this by killing off the bacteria that form dental plaque.8
Lowers Risk of Diabetes
• Elderly residents of a Mediterranean island had a 70% lower chance of having or developing type 2 Diabetes. An ensuing research study linked the phenomenon to their 1-2 cups a day tea habits.1
• According to a 2009 study, the polysaccharides in black tea were more effective at retarding the absorption of glucose than green & oolong teas. This led scientists to believe black tea constituents may have the ability to manage Diabetes.12
Primes Immune System
• Numerous studies, mainly animal so far, have shown the biological activities of black tea and its polyphenols to include anti-oxidant, anti-tumor, anti-inflammation and metabolic regulation.
• Tea polyphenols such as theaflavins and catechins are considered to be multifunctional compounds that could be effective in the prevention or treatment of various cancers, cardiovascular disease, chronic inflammation, obesity, metabolic syndrome, and neurodegenerative diseases.
• Perhaps the most fascinating study so far also helped to explain the role of an unusual, often called ‘enigmatic,’ subset of immune cells, specifically “T” cells (lymphocytes of a type produced or processed by the thymus gland and actively participating in the immune response) called Gamma delta T cells (γδ T cells). T cells of all types circulate around the body and either alert or attack antigens (a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies) according to their respective roles. γδ T cells, representing on average 5% of T cells, have been a mystery for some time.
• To appreciate the unusual relationship between black tea and Gamma delta T cells, a brief review of the 2 important parts of the immune system would be helpful:
The innate Immune System: The innate immune system is an evolutionarily older defense strategy, and is the dominant immune system found in all classes of plant & animal life.
Also known as the nonspecific immune system and the first line of defense, the innate immune system provides immediate defense against infection, acting as a physical and chemical barrier to infectious agents.
Unlike the adaptive immune system (which is found only in vertebrates), it does not confer long-lasting or protective immunity to the host.
Another important role is to activate the adaptive immune system.
• The adaptive immune system creates immunological memory after an initial response to a specific pathogen and leads to an enhanced response to subsequent encounters with that pathogen. This process of acquired immunity is the basis of vaccination.
The unique and relevant feature of the Gamma delta T cells (γδ T cells ) is that they function as a combination of the above two types of immunity, forming a basis for an exciting revised perspective on immune system biology. They combine adaptive immune system features with rapid, innate-like responses which places them in the initiation phase of immune reaction – a huge advantage in battling infections.13
• L-Theanine in black tea is a precursor (a biological substance from which another, usually more active or mature substance is formed) of ethylamine, a type of alkylamine. (Alkylamines are molecules found almost everywhere, including the blood, urine, breast milk, vaginal secretions and amniotic fluid of healthy individuals. They are excreted by bacteria and appear in high concentrations in tea and at lower concentrations in other foods like mushrooms, apples and wine. These alkylamines are identical to alkylamines found on tumour cells, bacteria, parasites and fungi, making them memorized targets for the immune system once spotted. Alkylamine antigens are thought to help keep the γδ T cells in a ready state, quickly able to respond to pathogens, especially those pathogens with alkylamine molecules, as the T cells can recognize them immediately as a potential health threat, since they have already been exposed to them in the tea. Whether from tea or bacteria, the γδ T cells will then ignore them or go on the offensive, accordingly.
• At the first sign of a pathogen, these now “primed” γδ T cells will excrete large volumes of antimicrobial cytokines (i.e. interferon, interleukin 2, and growth factors that impact other cells) within hours and expand 50-fold or more between 6 & 10 days after infection. They act within 24 hours to do away with bacterial infections and the expanded γδ T cells may have either an anti-inflammatory or antibacterial role, depending on what is required of them.14 Here’s the fascinating part:
• Since the tea alkylamines are identical to many pathogens’ alkylamines, the pathogen looks to be identical to the tea alkylamines. How do the γδ T cells determine who’s friendly and who’s not? Some scientists believe that the Gamma delta T cells have an empathetic response15 to determine friend or foe and act; they either pass it by or excrete interferon gamma, which was shown to destroy E. coli and Mycobacterium morganii in a pilot study of 11 people.14 However the distinction is made, it is accurately made and effectively executed.
In this study, the participants drank only 5-6 cups of black tea daily, to achieve this amount of immune response.
For diseases such as cancer, having higher levels of circulating Gamma delta T cells available produced the favorable observed outcomes needed.15
Black tea’s tannins have been found to reduce methicillin-resistant (antibiotic resistant) Staphylococcus aureus nasal colonization efforts.16
Stress Relief & Alert Relaxation
• Tea has been used in the Orient for years for its “calming and curative properties”. L-theanine, an amino acid in both green and black tea has been studied for its anxiolytic (used to reduce anxiety) effects. In clinical trials L-theanine increased alpha brain wave activity. Alpha waves are associated with a relaxed and alert mental state. Another type of brain wave, theta, is associated with drowsiness; Beta waves are associated with stress and anxiety.3
• Between 1% and 2% pf dry weight of tea leaves is L-theanine (gamma-ethyl-amino-L-glutamic acid).
High-grade Matcha tea, a specialty of SamsTeasandSpices, has the greatest percentage of L-Theanine.
• 2 human studies showed that within 30-40 minutes of consuming L-theanine, there was an increase in alpha wave activity, at which time the subjects perceived a change to a state of alert relaxation.
• The main difference between L-theanine and popular anti-stress herbs like Valerian, kava kava and St. John’s wort, is that L-Theanine does not promote drowsiness or promote sleep. So the next time you find yourself in a stressful situation, try a cup of our Vanilla Chai or Matcha tea and relax, without becoming sedated in the process!!
Safety & Interactions You Should Know About
• As widely consumed as it is today, black tea has no known safety issues.
• Side effects would be the same as any caffeine product – potential heartburn, gastritis & insomnia.
• Drug interactions can come into play, due to the caffeine. As a stimulant, consult a physician if using other stimulants, like Ritalin (for ADHD), MAO inhibitors (old class of anti-depressants).
• Folic acid (folate) is a B vitamin that's key for cell growth, metabolism, and for pregnant women. Black tea may decrease the absorption of this vitamin into the blood stream.
• L-Theanine in tea is safe for consumption and is not affected by consumption of food, so it can be taken at any time. If a person is already relaxed, taking tea will not produce further relaxation.
1. ’11 Benefits of Black Tea That You Didn’t Know About, LifeHack.org
2. Sales of Tea, American Botanical Council, Herbal EGram, Volume 11, Issue 11, November 2014
3. Constituents of Tea and Their Health Benefits, American Botanical Council, HerbClip, March 15, 2006
4. Theaflavins in black Tea and Catechins in Green Tea Are Equally Effective Antioxidants, Journal of Nutrition, Sept 1, 2001
5. Black tea theaflavins induce programmed cell death in cultured human stomach cancer cells, International Journal of Molecular Medicine, April 1, 1998
6. Flavonoids, Flavonoid Subclasses and Breast Cancer Risk: A Meta-Analysis of Epidemiological Studies, Plos One Journal, Jan. 18, 2013, journals. plosone.org
7. The Effect of Black Tea n Blood Pressure: A Systematic Review with Meta-Analysis of Randomized Controlled Trials, Plos One Journal, July 31, 2014, plosone.org
8. Anti-cariogenic effects of polyphenols from plant stimulant beverages (cocoa, coffee, tea), Fitotherapia Journal for the Study of Medicinal Plants, July 2009, journals.elsevier.com/fitoterapia
9. Increased Tea Consumption is Associated with Decreased Arterial Stiffness in a Chinese Population, Plos One Journal, Jan. 22, 2014, journals.plos.org/plosone
10. Tea Extracts Help Treat Damaged Skin in Cancer Patients, Biomed Central, Dec. 1, 2006, Sciencedaily.com/releases/2006
11. Theanine in Tea Causes Alert Reaction, American Botanical Council, HerbClip, August 6, 2001
12. Black Tea May Fight Diabetes, Science Daily, August 14, 2009, ScienceDaily.com
13. Six-of-the-best: unique contributions of γδ T cells to immunology, Nature Reviews Immunology Journal, Feb.2013, pgs. 88-100
14. Antigens in tea-beverage prime human Vγ2Vδ T cells in vitro and in vivo for memory and non-memory antibacterial cytokine responses, Arati B. Kamath et. al, PNAS, May 13, 2003, pnas.org
15. Defining the nature of human γδ T cells: a biographical sketch of the highly empathetic, Cellular & Molecular Immunology Journal, Jan. 2013, nature.com/cmi/focus/gamma_delta
16. Tannic Acid inhibits Staphylococcus aureus surface colonization in an IsaA-dependent manner, US National Library of Medicine, National Institutes of Health, .ncbi.nlm.nih.gov/PubMed
17. Impact of polyphenols from black tea and red wine/grape juice on a gut model microbiome, October 2013, sciencedirect.com