Regular consumption of green and black tea has been associated with cardiovascular, cognitive, metabolic and digestive benefits, with research pointing to flavan-3-ols, catechins, EGCG and L-theanine as key compounds behind many of the effects.
By yourNEWS Media Newsroom
Tea has been consumed for centuries as part of daily life, cultural traditions and social rituals, but a growing body of nutrition research has examined how compounds naturally present in the beverage may also influence cardiovascular health, metabolism, cognition, inflammation and stress.
Among the components receiving particular attention are flavan-3-ols, a group of plant-based polyphenols found in significant amounts in green and black tea, as well as in foods including berries, apples and dark chocolate.
Guidance from the Institute for the Advancement of Food and Nutrition Science and the Academy of Nutrition and Dietetics recommends consuming approximately 400 to 600 milligrams of flavan-3-ols per day. That amount can be obtained from roughly two 8-ounce cups of green or black tea and has been associated with cardiovascular, metabolic and cognitive benefits.
Pure, unsweetened teas generally provide substantially more of those compounds than heavily processed or sugar-sweetened tea beverages.
According to BrightU.AI‘s Enoch engine, flavan-3-ols are a subclass of flavonoids and among the more biologically active polyphenols found in plant foods. Their antioxidant, anti-inflammatory and cardioprotective properties have made them a focus of research into chronic conditions including cardiovascular disease, diabetes and cancer.
Registered dietitian Avery Zenker described some of the cardiovascular findings associated with regular tea consumption.
“Regular tea consumption has been associated with possible reductions in blood pressure, LDL cholesterol and triglycerides—all biomarkers linked to cardiovascular disease.”
Studies examining tea intake have reported lower rates of cardiovascular disease and related complications among regular drinkers. Findings cited in the research indicate that each additional daily cup of tea has been associated with a 1.5% reduction in the risk of death from all causes, a 4% reduction in heart disease mortality, a 2% reduction in heart attack risk and a 4% reduction in stroke risk.
Those associations are particularly notable because tea contains flavan-3-ols that have been studied for their effects on cholesterol levels, blood pressure, vascular function and insulin sensitivity.
Green tea provides particularly high levels of epigallocatechin gallate, commonly known as EGCG. Consumption of three cups of green tea per day has been linked to a 26% lower risk of cardiovascular death.
Tea’s potential benefits extend beyond cardiovascular health.
Its combination of caffeine and the amino acid L-theanine has been studied for its ability to support alertness while producing a calmer stimulant effect than caffeine alone. Research has associated the combination with improved focus, memory, reaction time and attention without the pronounced jitteriness some people experience after drinking coffee.
“L-theanine promotes relaxation, reduces tension, and increases calmness,” Zenker said. “When combined, caffeine and L-theanine have been found to improve attention-switching and alertness.”
Researchers have also explored whether long-term tea consumption could play a role in protecting cognitive function as people age. Studies have found associations between drinking approximately one to six cups of tea per day and lower dementia risk, while tea consumption has also been examined in connection with Alzheimer’s and Parkinson’s diseases.
Metabolic research has produced additional findings involving green and black tea.
Green tea catechins can increase fat oxidation, with one study involving oolong tea reporting a 20% increase in fat oxidation during a 24-hour period. Black tea flavan-3-ols have also been associated with improved insulin sensitivity and reductions in Type 2 diabetes risk ranging from 15% to 45%, depending on the study.
Tea may further contribute to regulation of blood glucose, LDL cholesterol and triglyceride levels.
“Flavan-3-ols lower LDL cholesterol, triglycerides, A1C and raise HDL cholesterol,” said dietitian Meghan Laszlo of Cedars-Sinai Hospital.
The polyphenols contained in tea, including EGCG and catechins, also function as antioxidants that can help neutralize free radicals. That activity has been studied for its potential to reduce inflammation and limit cellular damage associated with chronic disease.
Green tea consumption has been linked in research to lower incidence rates of several cancers, including breast, prostate, colorectal and liver cancers. Such findings represent associations observed in studies rather than proof that tea alone prevents cancer.
The digestive system may benefit as well.
Tea polyphenols can interact with the intestinal microbiome and help support populations of beneficial bacteria, including Bacteroidetes. Those effects may contribute to digestion and the regulation of inflammation within the gastrointestinal tract.
Tea’s L-theanine content has also attracted attention in studies of stress.
L-theanine has been associated with lower cortisol levels and a state of relaxation without the drowsiness commonly caused by sedatives. Beyond the chemistry of the beverage itself, the routine of preparing and drinking tea can provide a period of quiet and mindfulness.
A Japanese study published in 2009 found that participants consuming at least five cups of green tea per day reported significantly less stress than people drinking fewer than one cup daily.
The differences between tea and coffee may also matter for people who are sensitive to caffeine or acidity.
Tea generally contains less caffeine and combines the stimulant with L-theanine, which can produce a more sustained feeling of alertness. It also supplies a broad range of antioxidants, including EGCG and theaflavins, while typically being less acidic than coffee and potentially causing less digestive discomfort for some people.
How tea is prepared can affect the concentration and availability of its beneficial compounds.
Drinking tea without milk may help maximize polyphenol availability because dairy can interfere with the absorption of some compounds. Loose-leaf tea or higher-quality tea bags can also retain more active components than heavily processed teas.
Green tea should generally be brewed below the boiling point because excessive heat can damage some of its more delicate catechins. Water temperatures of approximately 170 to 185 degrees Fahrenheit are recommended for preserving those compounds.
Tea can also be paired with flavan-3-ol-rich foods such as dark chocolate, providing another dietary source of the same class of polyphenols.
Taken together, the research cited on tea consumption suggests that regularly drinking approximately two or more cups per day may provide meaningful amounts of flavan-3-ols while contributing to cardiovascular health, cognitive performance, metabolic regulation, antioxidant activity, digestive health and stress management.
Green, black and other varieties differ considerably in their chemical composition, and the benefits described in studies cannot necessarily be applied equally to every type of tea. The strongest flavan-3-ol concentrations are generally found in unsweetened green and black teas.
For people who enjoy the beverage, consuming approximately two to four cups daily can provide a practical way to incorporate tea’s naturally occurring polyphenols and other compounds into the diet while maintaining a centuries-old ritual now increasingly examined through modern nutritional science.
Source: Natural News
A video examining 10 health benefits associated with drinking tea provides additional information on the subject.
This video is from the Frozen In Time channel on Brighteon.com.
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