Tea Advisory Panel

Alertness / Fatigue

Ingredient compounds such as L-theanine and caffeine found in black tea may improve our attention span, according to various studies including those by Einöther SJL, Martens VEF, Rycroft JA, DeBruin EA.1

Tea is the main dietary source of L-theanine and is therefore almost universally consumed with caffeine. Studies have found that a combination of 97mg of L-theanine and 40mg caffeine for instance are associated with improvements in mental attention.

Findings from various studies have found that the L-theanine/caffeine combination drinks may improve attention span. This improvement was not only in visual attention span but also in hearing attention span. Such research is supported by other data including a published review,2 which investigated the health aspects of caffeine further.  The review concluded that optimal intakes of some caffeinated drinks such as tea, deliver key benefits in terms of mental function. In fact, the link between caffeine and health has been the subject of a large number of studies.

Black tea, in particular, contains polyphenols, which are a family of natural plant antioxidants. These have beneficial effects on many biochemical processes in the body because they help protect our cells against harmful free radicals and are anti-inflammatory. There is emerging data, which suggest that flavonoids can support brain and mental function. Take a look at the facts, stats and research below.



Einöther SJL, Martens VEF, Rycroft JA, DeBruin EA,. L-theanine and caffeine improve task switching but not intersensory attention of subjective alertness. Appetite 2010, doi:10.1016/j.appet.2010.01.003.
Nursing Standard, 4th November edition 2009

Articles and research (7)

Title Date Category Description  
How Tea Wakes You Up - infographic 20th Nov '17 Alertness / Fatigue Infographic - how tea wakes you up, by the Tea Advisory Panel
Brain up with tea 19th Nov '16 Alertness / Fatigue Both black and green tea are linked with improved cognitive function according to a new study, just published.
Brain up with tea: new study shows how tea improves brain function 29th May '15 Alertness / Fatigue Both black and green tea are linked with improved cognitive function according to a new study, just published.
Tea drinking linked with reduced cognitive decline 18th Jul '13 Alertness / Fatigue Tea drinking is linked with lower cognitive decline according to a new US meta-analysis just published by the American Society of Nutrition.
The benefits of black tea continually confirmed 7th Jun '11 Alertness / Fatigue Two studies just published provide further evidence of black tea's health benefits. One study revealed that black tea ingredients improve cognitive function, while the other found that black tea polyphenols could prevent obesity.
Clinical proof of the invigorating benefits of tea 13th Feb '09 Alertness / Fatigue A new research study has shown that tea really can be a pick-me-up - with the caffeine consumed by typical British tea-drinkers benefiting both mind and body without causing health concerns.
Drinking tea could be associated with better mental ability in older people 28th Jan '09 Alertness / Fatigue Regular consumption of tea could be associated with better cognitive performance according to a new Norwegian study involving over 2000 participants. Dr Catherine Hood, TAP member, comments on the study and what it means.

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