A recent article published in The Journal of Clinical Nutrition demonstrated the beneficial effect of constituents in green tea on attention span in adults. Specifically, participants in this study who consumed a combination of l-theanine and caffeine vs those who received placebo, scored higher in attention tasks. Furthermore, brain imaging results showed these substances had a tonic effect to visual modulation, suggesting greater visual accuracy.
L-theanine is an analog amino acid to glutamine. It has the ability to cross the blood-brain barrier and is generally believed to have a calming effect. According to drugs.com, " L-theanine may help relieve stress by inducing a relaxing effect without drowsiness. L-theanine as been shown to promote the generation of alpha-brain waves, an index of relaxation. It may also boost natural resistance to microbial infections and perhaps even tumors. Researchers suggest further isolating and refining L-theanine from tea to use it as a drug to boost the infection defense of the body. Although limited, there is clinical evidence to support these claims". Due to the fact that stress has been shown to negatively affect neuronal cells in the brain, this relaxing effect may explain the benefit of L-theanine in potentiating attention span.
What about caffeine? Caffeine is a xanthine alkaloid. It acts as a mild stimulant to the brain. According to Science Daily, caffeine may impede brain circulation while increasing alterness through stimulation of higher brain wave patterns.
In combination, l-theanine and caffeine may produce a synergistic effect. Caffeine's stimulating and brain modulating effects are combined with the calming effect of L-theanine to increase attention span.
L-theanine and caffeine are only two of many different constituents present in green tea. Studying only a few substances of an herbal remedy never gives the full, synergistic picture. Green tea has also been researchered for it's ability to modify inflammation via its polyphenol content and to inhibit inflammation through its potent antioxidant properties.
Just a note of caution relating to high caffeine intake is warranted before I close- as it may induce inflammation. According to a researcher from National Institute of Health, "it has been known for many years that caffeine interferes with the adenosine receptor. If, in fact, adenosine receptors are needed for effective inflammation control, anything that hinders their function might impair the body's ability to regulate inflammation."
References:
The modifying effects of green tea polyphenols on acute colitis and inflammation-associated colon carcinogenesis in male ICR mice. Kim M, Murakami A, Miyamoto S, Tanaka T, Ohigashi H. Biofactors. 2010 Jan 27.
Green Tea Polyphenols Prevent UV-Induced Immunosuppression by Rapid Repair of DNA Damage and Enhancement of Nucleotide Excision Repair Genes. Katiyar SK, Vaid M, van Steeg H, Meeran SM. Cancer Prev Res (Phila Pa). 2010 Jan 26. [Epub ahead of print]
PMID: 20103727
Antioxidant potential of tea reduces arsenite induced oxidative stress in Swiss albino mice.
Sinha D, Roy S, Roy M. Food Chem Toxicol. 2010 Jan 19.
Oplinger, A. Dampening the Flames: Inflammation Control Mechanism Determined. NIH News. 2001.
And what about coffee??
And what about coffee??
According to Dr. Mercola:
Most people are not aware that regular coffee consumption can be a significant source of pesticides. According to the CS Monitor, conventional farmers apply up to 250 pounds of chemical fertilizers per acre!
Pesticides contribute to a wide range of health problems, including prostate and other types of cancers, Parkinson's disease, and miscarriages in pregnant women.
So when you sip on your non-organic morning brew, you are also sipping on pesticide residues. Further, the U.S. has limited input and control over the type and quantity of pesticides used in the countries from which we import.
Since the vast majority of coffee, both organic and non-organic, consumed in the U.S. is grown outside this country, a return to non-organic farming of coffee beans in Latin America means a return to heavy use of pesticides.
Most people are not aware that regular coffee consumption can be a significant source of pesticides. According to the CS Monitor, conventional farmers apply up to 250 pounds of chemical fertilizers per acre!
Pesticides contribute to a wide range of health problems, including prostate and other types of cancers, Parkinson's disease, and miscarriages in pregnant women.
So when you sip on your non-organic morning brew, you are also sipping on pesticide residues. Further, the U.S. has limited input and control over the type and quantity of pesticides used in the countries from which we import.
Since the vast majority of coffee, both organic and non-organic, consumed in the U.S. is grown outside this country, a return to non-organic farming of coffee beans in Latin America means a return to heavy use of pesticides.
Other adverse affects of coffee include increasing blood pressure, raising cholesterol and insulin, damaging metabolism, increasing risk for osteoporosis, interfering with nutrient absorption, and affecting hormone levels.
My thoughts: Some studies do exhibit some potential benefits to coffee. Therefore, as with everything, listen to your body, use common sense, and be informed. If you are going to drink coffee, do yourself and your liver a favor- purchase fair trade organic.
Reisa Mehlman
Dr. Sarah Lobisco
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