Why drink tea? Most of us just drink it to warm and fill us up with as little effort and calories as possible. Yet there are many medicinal reasons to drink tea, too. I’ll begin my tea articles with a look at the health benefits of the standard black and green teas. In an article week, I’ll look at specific illnesses and the various other herbal teas that target them.
Black And Green Tea For Your Health
Tea is an important beverage. Herbal teas are even healthier than coffee, which I wrote about in a previous article. Whether for weight loss, an energy boost, improved mood and sleep or even to fight a winter cold virus, tea does the trick.
Teas are the most commonly consumed beverage in the world, second only to water.
Black And Green Tea
Black and green teas are both made from the shrub Camellia sinensis. The Chinese teas, oolong tea and white tea, also are made from this plant, but with preparation processes that significantly differ.
Black tea, the most oxidized type of tea, has a strong flavor that it maintains for many years. Because of the perceived value of black tea, it has even been compressed into bricks and used as a monetary currency in Mongolia, Tibet and Siberia.
Tea is renowned for its health benefits, and its effects on the body have been examined ever since Camellia sinensis was first used about 4,700 years ago in China. All the data on black and green tea show important health benefits.
Healthy Black Tea
In 2001,i researchers at Boston University found that among patients with cardiovascular disease, short- and long-term black tea consumption reversed vasomotor (blood vessel action) dysfunction. These scientists concluded that this effect on vessels was a major reason why drinking tea decreases heart attack rates.
A 2009 study reported in the Journal of Hypertensionii showed that black tea consumption improves blood flow and decreases arterial stiffness in healthy subjects. We also know that regular ingestion of black tea over six months results in lower systolic and diastolic blood pressure, according to a 2012 report in Food & Function.iii These are very important protective cardiovascular effects. Interestingly, a 2006 German study found that adding milk blocks the heart protective effects of tea.iv
Adding to the heart-healthy effects of black tea is its cholesterol benefits. Theaflavin-3-gallate is an advantageous compound found in black tea that is thought to improve cholesterol metabolism, according to a 2008 report in the Journal of Agricultural and Food Chemistry.v
Black and green teas contain L-theanine, known to promote nitric oxide (NO) production in the cells of the inner lining of arteries (endothelial cells). Nitric oxide is a well-known vasodilator that increases blood flow for improved skeletal muscle strength and also better cardiovascular health.vi L-theanine is used medicinally to reduce mental and physical stress and is one of the best remedies for adrenal fatigue. It is also known to improve mental clarity and boost mood in combination with caffeine.
Caffeine has a natural stimulant effect that can be beneficial for many health needs but can be overused and lead to a physical dependency. It is interesting to note that coffee has the highest caffeine content.
The approximate caffeine content per cup of various beverages include: drip coffee 100-150 mg, black tea 30-90 mg, Red Bull 80 mg, Mountain Dew 55 mg, Coca-Cola 45 mg, Pepsi-Cola 37 mg and Snapple Tea 32 mg.
Weight control may be another benefit of tea consumption. A 2010 report in the European Journal of Nutritionvii that looked at body weight and tea consumption among 6,472 study participants revealed a clear correlation: Drinking hot tea was inversely associated with obesity and directly associated with beneficial biomarkers of cardiovascular disease risk like increased HDL cholesterol and decreased C-reactive protein in men and women. In 2011, Japanese researchers reported nearly identical findings.viii They found that black tea consumption significantly reduced the risk of obesity and that it also could be used effectively to help prevent metabolic syndrome (prediabetes).
In the June 2009 Journal of Food Science, Chinese researchers found that green tea, oolong tea and black tea helped regulate blood sugar. They discovered that black tea was the most effective of these at slowing blood sugar absorption and fighting free radicals. ix
Green Tea For Health
Green tea shares the heart healthy and diabetes-reducing effects of black tea. Green tea is also known to have high concentrations of phytochemicals like polyphenolic compounds (most predominately epigallocatechin-3-gallate, or EGCG).
Similar to black tea, green tea consumption helps lower obesity and prevent metabolic syndrome. Remember, metabolic syndrome is the combination of obesity, high blood sugar (prediabetes), insulin resistance, hypertension and abnormal cholesterol levels.x It is thought that green tea ameliorates this condition with a modulation of dietary fat absorption and metabolism, increased glucose use, decreased new fat formation, enhanced blood vessel responsiveness (like black tea does) and antioxidant effects.
Moreover, researchers have found that green tea has cancer-reducing properties.
The association between high green tea consumption and low cancer rates in Asian countries is more than just coincidence. The chemicals in green tea have been shown to attach to and destroy cancer cells in animal studies. Studies show that these chemicals may stop cancer from forming in the skin, lung, mouth, esophagus, stomach, small intestine, colon, liver, pancreas and mammary glands.xi Other studies have shown that green tea’s actions prevent the spread of breastxii and prostatexiii cancers in humans.
My favorite teas to drink are green tea and fruit-flavored teas. These are low in calories because I sweeten them with stevia, not table sugar.
In my next article, I’ll talk about the many other health benefits from various herbal teas. I’m looking forward to exploring that topic.
To feeling good for life,
Michael Cutler, M.D.
Easy Health Options
i Stephen J. Duffy, MB, BS, PhD; John F. Keaney Jr, MD; Monika Holbrook, MA; Noyan Gokce, MD; Peter L. Swerdloff, BA; Balz Frei, PhD, "Short- and Long-Term Black Tea Consumption Reverses Endothelial Dysfunction in Patients With Coronary Artery Disease"; Joseph A. Vita, MD From Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Mass, and Linus Pauling Institute, Oregon State University, Corvallis.
ii Grassi D, Mulder TP, et al. Black tea consumption dose-dependently improves flow-mediated dilation in healthy males. Journal of Hypertension 2009 Apr;27(4):774-81.
iii Hodgson JM, Woodman RJ, Puddey IB, Mulder T, Fuchs D, Croft KD. Short-term effects of polyphenol-rich black tea on blood pressure in men and women. Food Funct. 2013 Jan 19;4(1):111-5. Epub 2012 Oct 5.
iv Mario Lorenz, Nicoline Jochmann, et al. “Addition of milk prevents vascular protective effects of tea”. Medizinische Klinik mit Schwerpunkt Kardiologie und Angiologie, Charité—Universitätsmedizin Berlin, CCM, Charitéplatz 1, D-10117 Berlin, Germany Institut für Biometrie und Klinische Epidemiologie, Charité—Universitätsmedizin Berlin, CCM, Charitéplatz 1, D-10117 Berlin, Germany.
v Theaflavins from Black Tea, Especially Theaflavin-3-gallate, Reduce the Incorporation of Cholesterol into Mixed Micelles. Mario A. Vermeer, Theo P. J. Mulder and Henri O. F. Molhuizen, J. Agric. Food Chem., 2008, 56 (24), pp 12031—12036.
vi Siamwala JH, Dias PM, et al. l-Theanine promotes nitric oxide production in endothelial cells through eNOS phosphorylation. J Nutr Biochem 2012 Jul 20. [Epub ahead of print] found online at: http://www.ncbi.nlm.nih.gov/pubmed/22819553
vii Vernarelli JA, Lambert JD. Tea consumption is inversely associated with weight status and other markers for metabolic syndrome in US adults. Eur J Nutr. 2012 Jul 10.
viii Kubota K, Sumi S, et al. Improvements of mean body mass index and body weight in preobese and overweight Japanese adults with black Chinese tea (Pu-Erh) water extract. Nutr Res. 2011 Jun;31(6):421-8.
ix Chen H, Qu Z, Fu L, Dong P, and Zhang X. Physicochemical Properties and Antioxidant Capacity of 3 Polysaccharides from Green Tea, Oolong Tea, and Black Tea. Journal of Food Science, June 30, 2009 Volume 74 Issue 6, Pages C469 - C474. Abstract online at http://www3.interscience.wiley.com/journal/122474198/abstract
x Sae-tan S, Grove KA, Lambert JD. Weight control and prevention of metabolic syndrome by green tea. Pharmacol Res. 2011 Aug;64(2):146-54.
xi Yang CS, Maliakal P, Meng X. Inhibition of carcinogenesis by tea. Annual Review of Pharmacology and Toxicology 2002; 42:25—54.
xii Shrubsole MJ, Lu W, et al. Drinking green tea modestly reduces breast cancer risk. J Nutr. 2009 Feb;139(2):310-6.
xiii Oct. 18, 2012—Men with prostate cancer who consumed green tea prior to undergoing prostatectomy had reductions in markers of inflammation, according to data presented at the 11th Annual AACR International Conference on Frontiers in Cancer Prevention Research, held in Anaheim, Calif., Oct. 16-19, 2012. Accessed online Jan 7, 2013 at: http://www.sciencedaily.com/releases/2012/10/121018121956.htm