Tea gets short shrift as coffee’s milder little sister. But these leaves may have a lot more to offer drinkers than just their subtle taste.
Large, observational studies have found lifelong tea drinkers are less likely to face early cognitive decline and get certain types of cancer, stroke, coronary heart disease, and type 2 diabetes.
We should also note that by “tea,” we mean the leaves from the Camellia sinensis plant that are plucked and processed in different ways to make black, green, white, oolong and pu’er teas -- not herbal infusions like peppermint, hibiscus and chamomile teas.
Researchers suspect that active ingredients in tea, like flavonoids, caffeine, fluoride and theanine, may have positive effects on our body’s functioning. However, observational studies can show an association between tea and a certain health benefit, but they don’t actually prove that drinking tea actually causes this outcome.
For the strongest evidence of tea’s benefits, scientists would need to do a randomized, controlled trial in which people would be assigned to either drink or avoid tea for 20 to 30 years, explains tea researcher Lenore Arab, a professor of medicine at the University of California, Los Angeles David Geffen School of Medicine. Or scientists would have to ask tea lovers to give up tea, or vice versa -- long-term, infeasible proposals.
The only randomized, controlled trials testing tea’s active ingredients on health outcomes are either animal studies or very short-term experiments in human beings. For instance, Arab has reviewed several animal experiments that found tea or tea’s active ingredients helped mitigate brain damage from stroke in rodents. And short-term RCTs in humans have found tea can help lower blood pressure and improve endothelial function (which is your blood vessels’ ability to respond to changes in blood flow) -- two things that help lower risk of cardiovascular disease.
So based on the evidence, should you drink tea for your health?
For people who already love tea, the answer is obvious: Yes, because tea is delicious and might also help us lead a longer, healthier life.
But for people who don’t like tea or aren’t used to it, the answers are a bit more complicated. Based on the current evidence, Arab can't recommend starting up a tea habit except to drink tea in place of soda, artificially sweetened drinks or juice. However, she did feel comfortable saying that both tea and water are healthy ways to hydrate yourself, and that tea might have a few more benefits than plain old water.
“If you drink tea, it has the advantage over water of providing fluoride and other active ingredients that we know affect blood supply,” said Arab. "And the cost is pretty low if you make your own tea and you don’t buy tea in a bottled water container. You don’t even know how much tea is in there.” Interestingly, Arab also pointed out that the UK’s preferred way of taking their tea -- with milk -- may negate some of the tea’s healthful properties.
“I’m a strong proponent of drinking tea and water as the primary beverage for people of all ages,” Arab concluded. “The only people in which it would not be recommended is very high doses in women who are pregnant, because of the caffeine."
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