So clearly, we're quite invested in the hot stuff—as is the freshly tea-pushing Starbucks—but what does it invest in us? New research into the relationship between nutrition and the brain is helping us to understand why tea time is such an essential part of the day—for the components of tea help us be more alert, more relaxed, and healthier over the long term.
As you may have experienced first-hand, caffeine has strong effects on people, most famously acting as a stimulant and reducing drowsiness.
As University of Chicago behavioral pharmacologist Emma Childs explains to us, caffeine increases alertness because it it prevents the sedative adenosine from working as a receptor.
"Adenosine has sedative effects," she says, "so by blocking those effects of adenosine, you're actually increasing central stimulation. You're actually increasing the activity of the central nervous system."
In this way, caffeinated beverages like tea give us more energy, since we're blocking the signal to our brains that we're tired. But don't mistake caffeine for rest: caffeine makes you less tired like an afternoon nap or an extra hour of sleep might, but it won't give you the depth of restoration or consolidation of memory that sleep provides.
Beyond the caffeine, tea has another killer app, and this one is unique to the leaf: Theanine, which is an amino acid present in black and green tea, especially the matcha, gyokuro, and anji bai cha varieties. A review of the research suggests that theanine reduces anxiety and calms us because it increases the number of inhibitory neurotransmitters (which balance our moods out) and modulates serotonin and dopamine (which makes make us feel good).
Huffington Post writer and naturopathic doctor Natasha Turner captures the causation:
Theanine works by increasing the production of GABA in the brain. Similar to the effects of meditation, it also stimulates alpha brainwaves naturally associated with deep states of relaxation and enhanced mental clarity. l-theanine may increase learning, attention and sensations of pleasure as well. These effects are likely due to the natural dopamine boost brought on by l-theanine. If you are wondering how something with caffeine can actually relax you, the L-theanine balances the stimulatory effects of caffeine so you stay alert without feeling jittery.
Tea is full of antioxidants like thearubigins, epicatechins, and catechins, which beyond being really fun to say have mightily excellent outcomes: they protect our cells from free radicals, therefore protecting against blood clots, cancer, or the hardening of the arteries. Additionally, the research suggests that regular tea drinkers have a lower risk of heart disease and stroke, plus lower cholesterol.
In other words, you don't need to be a tasseographist to know that drinking tea predicts a healthy, productive future.
Hat tip: Lifehacker