While green tea has a long-standing repute for well being advantages, analysis has been way more combined on black tea. One downside, says Maki Inoue-Choi, an epidemiologist on the Nationwide Most cancers Institute, is that giant observational research on tea and mortality have centered on nations like Japan or China—locations the place inexperienced tea is extra standard.
To fill this hole, Inoue-Choi and her colleagues analyzed knowledge within the United Kingdom, the place black tea ingesting is frequent. After surveying about 500,000 folks and following them for a median of 11 years, the outcomes, printed Aug. 29 within the journal Annals of Internal Medicine, gave black tea a lift. Among the many inhabitants of tea drinkers—89% of whom drank black tea, in comparison with 7% who drank inexperienced—ingesting tea was related to a modestly decrease mortality danger for many who had two or extra cups a day in comparison with non-drinkers. Individuals who added milk or sugar additionally skilled the profit, and the outcomes remained constant whatever the tea’s temperature. The findings additionally point out that tea drinkers had a decrease danger of dying from heart problems, ischemic coronary heart illness, and stroke than those that didn’t drink tea.
Whereas it’s tough to say why individuals who drink tea might reside longer, it’s not completely a shock. In response to Inoue-Choi, tea is “very wealthy in bioactive compounds” that cut back stress and irritation, together with polyphenols and flavonoids.
A 2020 study that used the identical British database as the brand new analysis discovered that there’s an affiliation between greater consumption of each black and inexperienced tea and biomarkers that predict cardiometabolic well being, together with decrease levels of cholesterol. Analysis has additionally steered that tea can assist decrease blood pressure.
Going ahead, researchers ought to take a more in-depth have a look at the connection between tea and heart problems, says Rob M. van Dam, professor of train and diet sciences at George Washington College’s Milken Institute Faculty of Public Well being, who didn’t take part within the examine. One putting factor concerning the new analysis, he notes, is that there isn’t an affiliation between growing the dose of tea—the quantity an individual consumes—and decreased mortality after the individual had consumed two or three cups. The exception, he mentioned, is if you happen to remove espresso drinkers, who might have made it tougher to identify an affiliation between growing the quantity of tea you drink and mortality as a result of they’d decrease mortality through the examine. With out the espresso drinkers, it grew to become clearer that ingesting tea was related to a decrease danger of dying of coronary heart illness. “The affiliation between tea consumption and cardiovascular mortality could also be driving the affiliation between tea consumption and all-cause mortality,” van Dam says.
None of that is to say, nonetheless, that you need to run to your kettle. The brand new analysis relies on an observational examine—which means that the proof wasn’t gathered from an experiment, and the outcomes have been inferred by the researchers. The findings shouldn’t be used to make well being choices, and should be replicated in randomized medical trials, specialists say. Plus, the magnitude of the affiliation between tea ingesting and mortality was modest, which implies it’s probably that one other attribute of people that drink tea might have led to this impact, says van Dam. For example, individuals who drink tea may hypothetically have been much less prone to eat soft drinks.
As Inoue-Choi put it, the brand new findings ought to be reassuring to individuals who drink tea often. However “folks shouldn’t change what number of cups of tea to drink every single day due to these outcomes,” she says.
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