Tea has been enjoyed across the world for centuries, starting in Asia and moving it’s way west. Coffee is newer to the scene. Originally an Arab drink, it became popular in Europe sometime around the 17th century. Everyone has their favorite, and many are quick to defend their choice, but which beverage really holds the upper hand from a health perspective?
In order to gain some insight, let’s break down a few key components of each drink.
Coffee has more caffeine than tea hands down. At around 100 to 150 mg per 8 oz. cup, coffee can provide that well needed energy boost in the morning. Caffeine is one of the main reasons people drink coffee, because of it’s ability to lift mood and increase focus. It acts as a stimulant on the central nervous system, improving reaction times and increasing mental clarity. About 15 minutes after consumption, the caffeine in a drink makes its way into your blood. Caffeine is able to easily cross the blood brain barrier because its chemical structure closely resembles the neurotransmitter adenosine. This resemblance also has the consequence of allowing caffeine to bind to adenosine. Since one of the jobs of adenosine is to control human sleep-wake cycles, this binding prevents activation of adenosine receptors. With more of these unbound receptors sitting around, dopamine uptake increases. As you probably know, dopamine is a neurotransmitter in the brain that affects mood, motivation, and cognition. This is what causes the feel good sensation during a caffeine rush.
For tea, caffeine content varies wildly by tea type, brand and brewing method. Brewed black tea generally contains about 45 mg caffeine, followed by oolong tea (~40 mg), green tea (~30 mg), and white tea (~25 mg). You’ll still get an energy boost from tea, but it will be much more subtle. This can be perfect for people more sensitive to caffeine.
The caffeine in tea has a slightly different effect on the body than coffee because tea contains an amino acid compound called L-theanine. In animal models, L-theanine works by increasing seratonin, dopamine, and GABA levels in the brain. GABA is actually an inhibitory neurotransmitter that reduces activity of the excitatory neurotransmitter glutamate, the primary agent responsible for anxiety. This is why a large class of anti-anxiety drugs called benzodiazepines, which include drugs like Xanax, Adivan, and Valium, work by enhancing the effect of GABA. It’s pretty cool that tea does this as well, and may be the reason why sipping a cup of tea is associated with relaxation. There is still research to be done on the subject, but several studies have come out indicating that L-theanine can help mitigate many of the negative side effects associated with caffeine and create a combined effect that improves focus even further.