Inexperienced, black, white and oolong teas all come from the identical plant, Camellia sinensis. Variations in flavour, color and look are largely decided by how the leaves are aged and processed
Natural tea. Photograph: Collected
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Natural tea. Photograph: Collected
Tea, the world’s second-most consumed beverage after water, has been linked to a spread of potential well being advantages, with many years of analysis pointing to the consequences of antioxidants, polyphenols and different plant compounds present in tea.
Researchers have described tea as “Nature’s reward for selling human well being”, though research have typically discovered associations moderately than establishing that tea straight causes higher well being outcomes, says The Washington Publish.
Inexperienced, black, white and oolong teas all come from the identical plant, Camellia sinensis. Variations in flavour, color and look are largely decided by how the leaves are aged and processed. Natural teas corresponding to chamomile, mint, hibiscus and ginger are comprised of herbs, flowers or spices moderately than tea leaves and usually include no caffeine.
Tea consumption and longevity
A 2023 examine utilizing information from the UK Biobank adopted about half one million individuals aged 40 to 69 in Britain for greater than a decade, analyzing their diets, beverage consumption, existence and well being circumstances.
About 90% of tea drinkers within the examine consumed black tea, whereas round 7% drank inexperienced tea. Researchers discovered that tea drinkers had decrease mortality charges than individuals who not often or by no means drank tea.
The strongest affiliation was amongst individuals who drank two to 3 cups a day, who had a 13% decrease threat of loss of life in the course of the examine interval than those that not often or by no means drank tea. The affiliation remained after accounting for espresso consumption.
A separate meta-analysis protecting about 2 million adults in North America, Europe, Asia and Australia additionally discovered an affiliation between tea consumption and decrease mortality.
Researchers warning, nonetheless, that such research can not set up a direct cause-and-effect relationship. Though elements together with alcohol consumption, bodily exercise, smoking and physique mass index had been thought of, different way of life and genetic elements may additionally affect the outcomes.
Potential cardiovascular advantages
Analysis has additionally linked common tea consumption with enhancements in cardiovascular well being.
A medical trial printed in Circulation adopted 66 adults with coronary artery illness who drank about three cups of black tea every day for 4 weeks and, throughout one other section, drank solely sizzling water.
The examine discovered that black tea consumption considerably improved vascular perform, a change related to elevated ranges of polyphenols within the bloodstream.
Different medical trials have discovered that ingesting both inexperienced or black tea recurrently for a number of weeks or months can produce a modest discount in blood strain.
Metabolic and immune results
Tea is just not thought of a method to stop Sort 2 diabetes, however medical trials counsel it could affect some facets of metabolic and immune perform.
Small trials have discovered that black tea can cut back blood sugar spikes after meals. In one other trial involving individuals with Sort 2 diabetes, members drank both three cups of black tea or three cups of sizzling water every day for 3 months.
These ingesting black tea confirmed a rise in regulatory T cells, immune cells that assist management irritation. Many members within the black tea group additionally recorded decrease ranges of C-reactive protein, a marker related to an infection, damage and systemic irritation.
Results on the intestine microbiome
Polyphenols in inexperienced and black tea may have an effect on the intestine microbiome by encouraging the expansion of useful micro organism.
Research have discovered that black tea consumption can improve micro organism that produce short-chain fatty acids. These compounds assist keep the colon lining, cut back native irritation and stimulate the discharge of GLP-1, a hormone concerned in urge for food regulation.
Cognition, alertness and stress
Tea additionally comprises caffeine, which may enhance consideration and cognitive efficiency, however analysis suggests it could intervene with sleep lower than espresso.
In a examine of 30 wholesome adults, members consumed both 4 cups of espresso or 4 cups of black tea every day. Each teams confirmed related enhancements in cognitive efficiency and application, whereas these ingesting tea skilled considerably fewer disruptions to their sleep at evening.
A 2017 assessment of analysis on inexperienced tea concluded that it may assist cut back nervousness and help reminiscence and a focus.
Black, inexperienced and white teas additionally naturally include L-theanine, an amino acid that analysis has related to lowered stress and improved temper.
