Introduction
Although drinking tea has been said to have health benefits for many centuries, only recently have its medicinal value been investigated empirically. There are four general categories of tea. These are green, black, white, and oolong tea. Black tea and green tea are the most common types. Black tea, which is obtained after fermentation and oxidation through fermentation, is the most commonly consumed kind. However, recent research indicates that some nutrients and elements are lost through oxidation. Green tea, which is the least unprocessed kind of tea, contains antioxidant polyphenols, especially the catechins believed to contribute to health benefits. Green tea is processed by passing steam over the freshly picked tea leaves to make them supple and soft, while preventing them from fermenting or discoloring. After steaming is done, the leaves are rolled, spread and “fired” to crispness. The greenish-yellow tea that results has a slightly astringent flavor which is likened to the taste of a fresh leaf. While green teas have health benefits, Black teas are largely associated with superior and distinct flavors. Research on the two kinds of teas has draw discourse and debate on which teas are medicinally better among the two. Despite the obvious superiority of green teas over black teas, due to the richness in antioxidants, consumption of black teas remains very high as compared to consumption of green teas. At the same time, the prevalence of the chronic diseases whose effects are reversed by consumption of green teas remains alarmingly high. This essay provides background on tea and presents arguments to support the claim that, green teas have better health properties as compared to black teas.
Background
Tea is a beverage obtained from the leaves of the tea plant (Camellia Sinensis). There are different ways of processing tea which lead to the different types of tea available. Green, black, white, oolong, and herbal tea are the five main types. Both black and green teas originate from the same plant. However, after harvesting, these teas are treated differently. Black tea undergoes oxidation (Sinija, & Mishra (233). This is done through the process of fermentation and chemical reactions which are caused by the exposure to oxygen. On the other hand, green tea is simply passed through steam and then “fired.” The process of oxidation causes chemical, flavor, and color changes. Oxidation, which is the process used in the production of black tea, leads to the loss of antioxidants which have been proven to have numerous health benefits. Catechins are naturally occurring chemicals with antioxidant properties. Antioxidants prevent the damage of free radicals in the body. The damage of these free radicals is believed to be the cause of many chronic diseases.
Relevance of research
There is a great need to educate people on the benefits of green tea, which contains considerably higher number of health-promoting antioxidants as compared to black tea. There are numerous researches pointing to the medicinal value of green tea. According to the Tea Association of America (1), over 154 million people drink tea every day. However, approximately 85% of these people drink iced tea. About 84% of the total amount of tea consumed in the United States is black tea (Tea Association of America, 1). Only 15% is green tea. All tea leaves have flavanoids after harvesting. The health benefits related to drinking tea are many. Predominant studies indicate a reduced risk of heart disease stroke, blood pressure and cholesterol. There is proof that consumption of green tea has a reversing effect on dementia and Alzheimer’s disease. Recent studies indicate a reduction in the proliferation of the cancer cells of rectal, skin and colon cancers. Despite these revelations, the number of people suffering from Dementia, rectal, skin and colon cancers, high blood pressure and obesity remains alarmingly high. These indicators point to a great need for increased sensitization of the public about the benefits of green tea. It also calls for further research in the area of naturally occurring antioxidants and their relationship to chronic diseases. The high number of people consuming tea illustrates how workable a campaign for an increase in the consumption of green tea is.
Green tea versus Black tea.
The benefits of green teas which are not provided by black teas are mostly health-related. However, these health benefits belong to different categories of human health, and they may be used to assert that green teas are better than black teas. First, green tea has anti-oxidants which delay the proliferation of cancer cells. Green tea contains antioxidants known as polyphenols. One of the most important and powerful polyphenols is known as (−)-epigallocatechin-3-gallate (EGCG). This polyphenol inhibits the proliferation of cancer cells while leaving healthy tissue unharmed. In addition, the results of an epidemiological study reveal that drinking green tea can reduce the risk of esophageal cancer in Chinese people by approximately 60%. These are not the only reports relating green tea polyphenols with the inhibition of cancer cells. Fujiki, Suganuma and Kurusu (120) indicate that tea catechins have an inhibitory effect on the release of the tumor necrosis factor-alpha, which has been associated with tumor progression in initiated cells and premalignant cells. EGCG has been shown to decrease the binding of the okadaic acid-type and the 12-Otetradecanoylphorbol-1-3-acetate (TPA) promoters of tumor growth to their receptors. This is known as “sealing” effect, which is achieved through its interface with the phospholipid layer of the cell membrane. The value of green tea in treating skin problems has been with the Chinese for many centuries. Today, research indicates that the tumorigenesis can be inhibited by green tea polyphenols (Bertolini, Fusetti, Rabascio, Cinieri, Martinelli, and Pruneri 1480). These researches indicate that green tea inhibits the growth of cancerous cells. On the other hand, black tea does not have any components with proven anti-carcinogenic effects.
Secondly, green tea has proven to have numerous antioxidant applications such as anti-inflammatory treatment and antibiotic functions. Polyphenolic constituents of green tea have anti-inflammatory functions, while, in black tea, these polyphenols are non-existent. Green-tea polyphenols also help the skin by modulating biochemical pathways which are involved in responses to inflammation, cell proliferation and tumor promotion. Experiments indicate that when the skin of a mouse is treated with EGCG, oxidative stress and UVB-induced immunosuppression are prevented. Green tea extracts are being used today for pharmaceutical and cosmetic purposes in supplementing the constituent compounds found in skin-care products. Dying human keratinocytes are reactivated upon exposure to EGCG. Skin cells usually migrate toward the surface of the skin as they near death. This process takes 28 days. Today, research shows that EGCG reactivates these epidermal cells (Lee, Maliakal, Chen 1028). Green tea extracts are also associated with anti-fungal activity. The anti-fungal properties of catechin have been documented severally in research. Continuing research is aimed at reducing the shortcomings of anti-myocotics. These properties and advantages are not prevalent in black tea. Oxidation (fermentation) kills the tea extracts which are proving very useful in green tea.
Thirdly, according to Sinija, & Mishra (235), compounds in green tea improve brain function and cognitive ability. Green tea does not only stimulate brain function but also improves brain activity. By raising the concentration of neurotransmitters such as norepinephrine and dopamine, as well as firing of neurons, green tea stimulates. In addition to this, it contains L-theanine which and catechins which have neuroprotective functions that have been proven to ameliorate neurodegenerative diseases such as Alzheimer’s disease (AD) as well as Parkinson disease (PD). EGCG invokes various cellular mechanisms which have neuroprotective, as well as neurorescue properties. This implies that green tea is a good start against dementia among the aging population. A study by Kuriyama, Hozawa, Ohmori, Shimazu, Matsui, Ebihara, Awata, Nagatomi, Arai, and Tsuji (357) showed that there are inverse-dose response relations between green tea consumption and prevalence of cognitive impairment. On the other hand, a weak relationship between black or oolong tea consumption and cognitive impairment was observed. The improved mental performance, coupled with evidence of improved memory after consumption of green tea points to its superiority over black tea in terms of medicinal value.
Misconceptions about green and black tea
There are various misconceptions on black tea and green tea. The firs misconception is that black tea has more caffeine than green tea. This is totally incorrect. Despite common beliefs, the color of the tea does not indicate the levels of caffeine. The only variation in caffeine levels in teas occurs as a result of differences in age. Younger leaves produce teas which have higher caffeine levels than old leaves. The color of tea comes from the method used in processing the tea. Another common misconception is that pregnant women should not drink green teas. Pregnant women can drink green tea but must maintain the 200mg caffeine limit per day. It is beneficial for pregnant women to drink only one cup of tea because it has very useful antioxidants which inhibit cell damage. However, consulting a physician is very important. The third common misconception is that green tea, oolong tea, and black tea are derived from different plants. This is not the case. All teas come from the same plant and the differences arise from the manner in which they are processed.
Conclusion
Over the years, consumption of tea has been linked to health benefits. However, only recently has empirical research been used to show these health benefits. Green tea has more health benefits than black tea despite it having poor consumption levels in the United States. At the same time, occurrence of various cancers, diabetes, obesity, Alzheimer’s disease and dementia remains alarmingly high. Among the health benefits that make green teas medicinally superior to black teas include proven inhibitory function over proliferation of cancer cells; anti-inflammatory functions; and the improvement of memory and cognition. This means that the American public should be sensitized on the health benefits of replacing their consumption of black tea with that of green teas. As proven by research, it is a good starting point to fight chronic diseases and reverse the degeneration of memory and cognitive functions in the elderly.
Work Cited
Bertolini F, Fusetti L, Rabascio C, Cinieri S, Martinelli G, Pruneri G. Inhibition of angiogenesis and induction of endothelial and tumor cell apoptosis by green tea in animal models of human high grade non-Hodgkin’s lymphoma. Leukemia 2000;14:1477–82.
Fujiki H, Suganuma M, Kurusu M. New TNF-alpha releasing inhibitors as cancer preventive agents from traditional herbal medicine and combination cancer prevention study with EGCG and sulindac or tamoxifen. Mutat Res 2003;523–4:119–25.
Kuriyama, Shinichi , Atsushi Hozawa, Kaori Ohmori, Taichi Shimazu, Toshifumi Matsui , Satoru Ebihara, Shuichi Awata , Ryoichi Nagatomi, Hiroyuki Arai, and Ichiro Tsuji. "Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project 123." American Society for Clinical Nutrition 83.2 (2006): 355-361. Print.
Lee MJ, Maliakal P, Chen L. Pharmacokinetics of tea catechins after ingestion of green tea and (-)-epigallocatechin-3-gallate by humans: formation of different metabolites and individual variability. Cancer Epidemiology Biomarkers Prevent 2002;11:1025–32.
Sinija, V. R., and H. N. Mishra. "Green Tea: Health Benefits." Journal of Nutritional & Environmental Medicine 17.4 (2008): 232-242. Print.
Tea Association of America. "Tea Fact Sheet." Tea USA News. Version 1. Tea Association of America, 3 Apr. 2013. Web. 14 Apr. 2014. <http://www.teausa.com/14655/tea-fact-sheet>.
