Tweet
By Greg Arnold, DC, CSCS, October 10, 2006, abstracted from “The effects of tea on psychophysiological stress responsivity and post-stress recovery: a randomised double-blind trial” printed online September 30, 2006 in the Journal of Psychopharmacology
Although green tea is regarded as the tea with the most health benefits, research has started to focus significantly on black tea, due to its properties that help enhance mood,1 maintain alertness over the day,2 and even promote heart health.3 In fact, recent reviews have found that black tea’s health benefits are comparable to green tea.4
Now a new study5 has found more benefits of black tea on mood, which may help people better deal with stress.
Building upon previous research showing teas effects on the nervous system6 including brain function,7 75 healthy non-smoking men were withdrawn from drinking tea, coffee and caffeinated beverages for four weeks. Following this “washout” phase, they were given either a treatment of tea or placebo for six weeks. The daily tea treatment consisted of a total 1,050 mg of black tea and was the equivalent of drinking four cups of black tea per day. They then underwent tests for stress that included measurements of cortisol, blood clotting and completion of behavioral tasks.
At the end of six weeks, while they found that increases in blood pressure and heart rate did not differ between the two groups after the tasks. Blood clotting and cortisol levels were significantly lower and feelings of relaxation were significantly higher after the tasks in the tea group compared to the placebo group.
For the researchers, “tea consumption leads to lower post-stress cortisol and greater subjective relaxation, together with reduced platelet activation. Black tea may have health benefits in part by aiding stress recovery.” These results are the latest in a number of studies on the health benefits of tea and the catechin EGCG. Studies on green tea and Alzheimer Disease were reported in 20058 and 2006.9
Greg Arnold is a Chiropractic Physician practicing in Danville, CA. You can contact Dr. Arnold directly by emailing him at mailto:ChiroDocPSUalum@msn.com or visiting his web site www.CompleteChiropracticHealthcare.com
Reference:
1 O’Brien DC (2000) The acute physiological and mood effects of tea and coffee: the role of caffeine level. Pharmacol Biochem Behav 66:19–28
2 Lane J (2000) A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality. Psychopharmacology (Berl) 149:203–216
3 Gardner EJ. Black tea – helpful or harmful? A review of the evidence. Eur J Clin Nutr advance online publication, July 19, 2006; doi:10.1038/sj.ejcn.1602489
4 G. B. Maru (2005). "Inhibitory effect(s) of polymeric black tea polyphenols on the formation of B(a)P-derived DNA adducts in mouse skin." J Environ Pathol Toxicol Oncol 24(2): 79-90
5 Steptoe A. The effects of tea on psychophysiological stress responsivity and post-stress recovery: a randomised double-blind trial. Psychopharmacology (Berl). 2006 Sep 30; [Epub ahead of print]
6 Tamargo J (2002) Endothelium-independent vasodilator effects of the flavonoid quercetin and its methylated metabolites in rat conductance and resistance arteries. J Pharmacol Exp Ther 302:66–72
7 Juneja LR, Chu DC, Okubo T, Nagato Y, Yokogoshi H (1999) l-theanine: a unique amino acid of green tea and its relaxation effect in humans. Trends Food Sci Technol 10:199–204
8 Tan J. Green Tea Epigallocatechin-3-Gallate (EGCG) Modulates Amyloid Precursor Protein Cleavage and Reduces Cerebral Amyloidosis in Alzheimer Transgenic Mice J. Neurosci. 2005 25: 8807-8814
9 Cooper R. Medicinal benefits of green tea: Part I. Review of noncancer health benefits. J Altern Complement Med. 2005 Jun;11(3):521-8
Although green tea is regarded as the tea with the most health benefits, research has started to focus significantly on black tea, due to its properties that help enhance mood,1 maintain alertness over the day,2 and even promote heart health.3 In fact, recent reviews have found that black tea’s health benefits are comparable to green tea.4
Now a new study5 has found more benefits of black tea on mood, which may help people better deal with stress.
Building upon previous research showing teas effects on the nervous system6 including brain function,7 75 healthy non-smoking men were withdrawn from drinking tea, coffee and caffeinated beverages for four weeks. Following this “washout” phase, they were given either a treatment of tea or placebo for six weeks. The daily tea treatment consisted of a total 1,050 mg of black tea and was the equivalent of drinking four cups of black tea per day. They then underwent tests for stress that included measurements of cortisol, blood clotting and completion of behavioral tasks.
At the end of six weeks, while they found that increases in blood pressure and heart rate did not differ between the two groups after the tasks. Blood clotting and cortisol levels were significantly lower and feelings of relaxation were significantly higher after the tasks in the tea group compared to the placebo group.
For the researchers, “tea consumption leads to lower post-stress cortisol and greater subjective relaxation, together with reduced platelet activation. Black tea may have health benefits in part by aiding stress recovery.” These results are the latest in a number of studies on the health benefits of tea and the catechin EGCG. Studies on green tea and Alzheimer Disease were reported in 20058 and 2006.9
Greg Arnold is a Chiropractic Physician practicing in Danville, CA. You can contact Dr. Arnold directly by emailing him at mailto:ChiroDocPSUalum@msn.com or visiting his web site www.CompleteChiropracticHealthcare.com
Reference:
1 O’Brien DC (2000) The acute physiological and mood effects of tea and coffee: the role of caffeine level. Pharmacol Biochem Behav 66:19–28
2 Lane J (2000) A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality. Psychopharmacology (Berl) 149:203–216
3 Gardner EJ. Black tea – helpful or harmful? A review of the evidence. Eur J Clin Nutr advance online publication, July 19, 2006; doi:10.1038/sj.ejcn.1602489
4 G. B. Maru (2005). "Inhibitory effect(s) of polymeric black tea polyphenols on the formation of B(a)P-derived DNA adducts in mouse skin." J Environ Pathol Toxicol Oncol 24(2): 79-90
5 Steptoe A. The effects of tea on psychophysiological stress responsivity and post-stress recovery: a randomised double-blind trial. Psychopharmacology (Berl). 2006 Sep 30; [Epub ahead of print]
6 Tamargo J (2002) Endothelium-independent vasodilator effects of the flavonoid quercetin and its methylated metabolites in rat conductance and resistance arteries. J Pharmacol Exp Ther 302:66–72
7 Juneja LR, Chu DC, Okubo T, Nagato Y, Yokogoshi H (1999) l-theanine: a unique amino acid of green tea and its relaxation effect in humans. Trends Food Sci Technol 10:199–204
8 Tan J. Green Tea Epigallocatechin-3-Gallate (EGCG) Modulates Amyloid Precursor Protein Cleavage and Reduces Cerebral Amyloidosis in Alzheimer Transgenic Mice J. Neurosci. 2005 25: 8807-8814
9 Cooper R. Medicinal benefits of green tea: Part I. Review of noncancer health benefits. J Altern Complement Med. 2005 Jun;11(3):521-8
Comment