Green Tea or Black Tea: Is One Healthier?
By Molly Knudsen, MS, RDN
Is there anything a cup of tea can’t do?
- Morning pick-me-up? Check
- Warming your body from the inside out after a cold day? Check
- Soothing a tender throat? Check
- Tasting delicious? Check
- Contributing to a healthful diet? Check
This beverage is just as popular as it is versatile. Besides water, tea is the most widely consumed drink on the planet.1 And it’s been a go-to brew for thousands (and thousands) of years. Tea cultivation originated in China and India and played integral roles in both traditional Chinese medicine and culture as well as in Ayurveda medicine.2 Tea then spread to Japan and later to Europe by Portuguese traders and missioners living in Asia.3
What is tea and how is it made?
Now, the term tea is specific to the beverage made from steeping the leaves of the Camellia sinensis in hot water. So technically herbal teas like chamomile, peppermint, and lavender do not fit this definition. Rather, herbal teas are infusions from the leaf, stems, bark, or fruit of various plants.
The three main tea varieties that stem from Camellia sinensis are green, black, and oolong. It’s the harvesting and processing methods of the leaves that are responsible for the teas’ distinct differences.4
To make green tea, freshly harvested leaves are withered to remove any moisture, steamed, and then dried.4 Steaming is an important step because it prevents fermentation of the leaf and allows the leaf to maintain its color before the rolling and drying process begins.4 And can you guess what that color is? Green. So green tea is NOT fermented, and preserving the color of the leaf means that green tea maintains a lot of polyphenols that are beneficial for health.5
Black tea is also known as fermented tea. During the production of black tea, tea leaves are exposed to the air for several hours to allow oxidation to occur and enzymatic reactions to carry out the fermentation process, unlike in green tea production. Exposure to the air causes the leaves to turn a dark brown color and intensifies the flavor.4 The leaves are then heated, topping off the black tea processing.
Oolong tea is made by partial fermentation of the leaves. The leaves aren’t exposed quite as long to air as in black tea processing, nor are they steamed immediately like in green tea processing. This tea falls somewhere in the middle of its two more extreme counterparts.
Tea enthusiasts may be noticing right about now a couple of teas that haven’t been covered yet. And you’re right. White tea and Pu-erh tea are also derived from the Camellia sinensis plant. White tea is processed similarly to green tea, but it is made from unopened buds or immature leaves from the plant.6 Pu-erh tea is more similar to a black tea, and processing involves both oxidation and a fungus-led fermentation of larger leaves from a specific variety of Camellia sinensis.6
Is one tea healthier? The health differences between the green and black tea
There are a couple of nuances to discuss before really digging into this question. First is that scientific studies are needed to draw conclusions on the healthfulness and the impact of tea consumption and health. And some studies don’t differentiate between type of tea consumed. They just look at overall tea consumption. Research shows that total consumption of tea, regardless of type, is associated with both heart health and cognitive health.7
Secondly, there has been a lot more research conducted on green tea consumption compared to any other tea.5 Since green tea has been studied the most in relation to health, it’s easier to draw more direct conclusions about its impact on health. Black tea is the second most researched tea, but studies specifically on oolong, white, and Pu-erh tea are few and far between.
Since green tea and black tea are the most starkly different of the tea types based on processing methods and have the most research investigating their impact on health, the question is really… Is green tea or black tea better for you?
Green tea: Green tea has the highest amount of polyphenols of all the teas and is especially rich in a class of polyphenols called catechins.1 These catechins have antioxidant properties, and the health benefits of green tea are often attributed to its antioxidant capabilities.1 Epigallocatechin 3-gallate or EGCG is the most abundant and the most potent catechin in green tea.1 Although smaller amounts of EGCG can be found in fruits and nuts, green tea is the best natural source of EGCG.1 EGCG can also be extracted from green tea and found in supplements.1
Several studies that followed large groups of people over time and several randomized controlled trials found green tea consumption to be positively associated with weight status, heart health, and maintaining healthy blood cholesterol and blood pressure levels.8,9 Benefits from these studies were typically seen in those consuming anywhere from one to five cups of green tea per day, or sometimes even upward of 6 cups (or about eight to 48 ounces give or take) a day.8
Green tea may also play a role in healthy aging. A study published in 2019 looked at the relationship between green, black, or no tea consumption on the successful aging index on adults over 50 years old living in the Mediterranean region.7 After accounting for age, sex, smoking status, and coffee consumption, green tea consumption was associated with healthier aging, while black tea was not.7
Black tea: Black tea has a similar total polyphenol count to green tea but with different constituents. The catechin content of black tea is much lower, as the oxidation and fermentation process of black tea converts catechins to theaflavins and thearubigins (different polyphenols).4,7 These polyphenols also act as antioxidants.10 Research shows that black tea may also play a role in heart health, support antioxidant status in the body, and support endothelial health (which influences blood pressure).10
So there are benefits to drinking both green tea and black tea, and neither beverage is considered harmful. And while the current research does show that green tea is associated with the most significant effects on human health compared to other teas, it is also considered a proxy for other healthy lifestyles.5,7 So yes, green tea is healthy. But people who drink green tea also tend to lead an overall healthier lifestyle.7
What are the similarities and shared benefits of drinking tea?
As mentioned in the previous section, total tea consumption is associated with measures of health, and the differences between types seem to lie within the types of polyphenols present in the tea. But there are also a lot of similarities since they’re derived from the exact same plant. Here are some common components that are found in ALL teas.
- Caffeine: There are slight variances in the overall caffeine content per cup of tea, with black tea having the most at 48 mg and green having the least with around 28.8 mg, but caffeine is a natural compound in all teas.11 And it’s a much lower source of caffeine than a regular cup of coffee that has around 96 mg per cup, which is associated with some perks.11 Research shows that low doses of caffeine similar to what would be found in a single cup of tea consumed throughout the day have been shown to improve speed of perception and may result in more consistent levels of what is considered “simple task performance.”12
- L-theanine: Tea is pretty much the exclusive, natural source of an amino acid called L-theanine. And this amino acid is suspected to have an interesting interaction with caffeine. It is well known, AKA scientifically documented and likely personally experienced, that too much caffeine or even small to moderate amounts of caffeine for some people can lead to jitters and restlessness and a quickened heart rate.13 It’s suspected that L-theanine may dampen those type of responses. And a study showed that the combination of L-theanine and caffeine at low doses support the ability to focus as well as play a role in speed and accuracy of certain tasks, suggesting a synergistic relationship between these two components.14
- Flouride: Tea is a natural source of fluoride. The amount found in green, black, and oolong tea are all relatively similar and are within the levels that have been shown to promote dental health.15
What’s the key takeaway?
Tea is a tasty and versatile beverage. The research to date suggests that green tea may be the most healthful variety due to its high amount of catechins and antioxidant capabilities. However, ALL types of tea have nutritional merit and can be beneficial to health. If you’re currently a tea drinker or want to add tea into your daily routine, pick the tea that you enjoy drinking the most. And remember, keep additives like sugar or cream to tea limited and be mindful of caffeine consumption later in the day.
- Forester SC et al. Mol Nutr Food Res. 2011;55(6):844-854.
- Chopade VV et al. Phcog Rev. 2008;2(3):157-162.
- The history of tea. Tea.co.uk. https://www.tea.co.uk/history-of-tea. Accessed October 5, 2020.
- Khan N et al. Curr Pharm Des. 2014;19(34):6141-6147.
- Chacko SM et al. Chin Med. 2010;5(13).
- Tea. Lpi.oregonstate.edu. https://lpi.oregonstate.edu/mic/food-beverages/tea. Accessed October 1, 2020.
- Naumovski N et al. Molecules. 2019;24(10):1862.
- Yang CS et al. Mol Nutr Food Res. 2016;60(1):160-174.
- Pang J et al. Int J Cardiol. 2016;202:967-974.
- Gardner EJ et al. Eur J Clin Nutr. 2007;61:3-18.
- FoodData Central. Fdc.nal.usda.gov, Accessed October 1, 2020.
- Bryan J et al. Nutr Rev. 2008;66(2):82-90.
- Spilling the beans: How much caffeine is too much?. Fda.gov. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much. Published December 12, 2018. Accessed October 6, 2020.
- Parnell H et al. Nutr Neurosci. 2008;11(4):193-198.
- Goenka P et al. Pharmacogn Rev. 2013;7(14):152-156.