After water, tea is the world’s most popular beverage, consumed by nearly two-thirds of people across the globe.
Because of this, scientists have spent decades carrying out hundreds of studies on tea’s potential health benefits.
Scientists have found that the compounds in tea can protect your blood vessels, lower inflammation, aid relaxation and potentially boost your gut microbiome. In one analysis published in the journal Life Sciences, researchers described tea as “Nature’s gift for promoting human health.”
This is in large part because a typical cup of brewed tea contains many antioxidants, polyphenols and other beneficial plant compounds, much like coffee, cocoa, fruits and vegetables, said Jenifer Bowman, a cardiac dietitian at UCHealth in Fort Collins, Colorado.
Although green, black, white and oolong teas look very different, they all come from the same plant: Camellia sinensis. What determines their distinct flavors and appearance are how the tea leaves are aged and processed. Then there are herbal teas, such as chamomile, mint, hibiscus and ginger. These are made by brewing spices, herbs and flowers. Herbal teas have varying levels of polyphenols and typically do not contain caffeine.
Much of the research on the health benefits of tea has focused on black and green tea, which are the world’s most widely consumed tea varieties. But scientists have found that herbal teas can boost your health in various ways as well.
Here’s what else to know about the health benefits of drinking tea.
A boost for longevity
One of the most consistent scientific findings about tea consumption is that tea drinkers tend to live slightly longer than people who do not drink tea.
In one large study published in the Annals of Internal Medicine in 2023, researchers compared tea drinkers to non-tea drinkers in the United Kingdom. The scientists tracked roughly a half million adults between the ages of 40 and 69 for more than a decade, looking at their diets, beverage consumption, lifestyle habits, and overall health and medical conditions.
About 90 percent of the tea drinkers in the study drank primarily black tea, while about 7 percent said they drank green tea. The researchers found that the tea drinkers were less likely to die during the study period compared with the non-tea drinkers. People who drank two to three cups daily seemed to benefit the most: They had a 13 percent reduction in mortality compared with people who rarely or never drank tea. The findings were essentially the same regardless of whether people also drank coffee or not.
Similar results have been seen across many large studies, including a rigorous meta-analysis involving roughly 2 million adults in North America, Europe, Asia and Australia.
The research showed only a correlation, not cause and effect. Although the scientists took factors like alcohol consumption, physical activity levels, smoking and body mass index into account, it’s possible that other factors played a role.
Cardiovascular benefits
Many studies have found that drinking tea protects and relaxes your blood vessels, which can boost your cardiovascular health.
In one study in the journal Circulation, scientists wanted to see how black tea would affect vascular health, so they recruited 66 adults with coronary artery disease and assigned them to drink roughly three cups of black tea every day for four weeks. In a separate phase of the trial, the participants were assigned to drink only water each day instead of tea.
The researchers found that drinking black tea improved vascular function, and that the improvements appeared to be driven by increased levels of polyphenols in the participants’ blood.
Multiple clinical trials have also found that both black tea and green tea can slightly lower blood pressure when consumed on a daily basis for weeks or months at a time.
Improvements in metabolic health
Drinking tea isn’t going to prevent Type 2 diabetes. But it may improve several aspects of your metabolic health. Small clinical trials have found that drinking black tea can help reduce blood sugar spikes after a meal.
Scientists have discovered that tea consumption also has beneficial effects on inflammation and the immune system.
In one clinical trial, scientists recruited people with Type 2 diabetes and assigned them to drink either three cups of black tea every day for three months or three cups of plain hot water. When people drank black tea, they had increases in a special type of immune cell that suppresses inflammation, known as regulatory T cells. Many of the participants also had reductions in their levels of C-reactive protein, a molecule that rises when your body has an infection, injury or is experiencing a lot of inflammation.
A boost for gut health
Black and green tea are rich sources of polyphenols. These plant compounds, which are found in many fruits and vegetables, act like fertilizer for your gut, stimulating the growth of beneficial bacteria, said Chris Damman, a microbiome expert and gastroenterologist at the digestive health center at the University of Washington Medical Center.
Studies have found, for example, that drinking black tea can increase the abundance of bacteria in your gut that produce short-chain fatty acids, which are special compounds that protect your colon, lower inflammation and stimulate the release of the appetite-suppressing hormone GLP-1.
Cognitive benefits
If you need to hunker down and get some work done, then a cup of tea or coffee will help you focus. That’s because they both contain caffeine, which boosts your alertness and attention span. But for many people, tea may be the better option because it’s less likely to wreck your sleep.
In one study, scientists recruited 30 healthy adults and looked at what happened when they instructed them to drink either four cups of coffee daily or four cups of black tea. The researchers found that both coffee and tea produced similar improvements in alertness and cognitive performance. But people experienced fewer sleep disruptions at night when they consumed tea on a daily basis compared with when they drank coffee.
Researchers have also found that drinking tea promotes relaxation. A scientific review published in 2017 looked at decades of research on the cognitive effects of drinking green tea and concluded that it reduces anxiety, and aids memory and attention.
Scientists think this is in part because black, white and green tea contain l-theanine, an amino acid that has been shown to help relieve stress and improve mood.
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