Green tea and matcha are all the rage right now. People are touting the health benefits left and right, and even some die-hard coffee drinkers made the switch. But is it actually good for you? I've done some in-depth research and collected the facts below.
Here's what I found out about matcha and green tea:
1. What matcha is and how it's different from green tea
2. The active ingredients in green tea and their benefits
3. Ingredients in green tea that have adverse side effects
4. When and how much green tea you can and should drink
5. The best kind of green tea or matcha to buy
For the sake of simplicity, unless I'm describing a difference between the two, I will refer to matcha as "green tea" for the remainder of this article.
Please also note that you may have heard of other benefits or risks from drinking green tea or matcha. I only listed information in this article that comes from clinical trials with conclusive results involving human subjects. If a proposed effect was based on animal testing, folk medicine, or an inconclusive human study, then it is not listed here. I also tried to avoid publications where the results were not peer-reviewed, the research was sponsored by a company with a vested interest in the results, or one of the researchers was employed by a company that could present a conflict of interest.
How is matcha different from green tea?
If you buy something labeled "green tea," it's likely to come in a tea bag or maybe loose leaves. You steep it in hot water as you would with other types of tea, and then discard the leaves or bag and drink the infused water.
Matcha comes from the same plant as green tea, called Camellia Sinensis. However, matcha is the leaves ground into a fine powder. To prepare it as a tea, you also mix it with hot liquid, but the powder remains in the drink. Therefore you receive a more concentrated dose when you drink matcha.
Benefits of drinking green tea
Unlike black tea, where leaves go through fermentation, green tea is minimally processed. Gentle manufacturing preserves its level of catechins, specifically EGCG. In a systematic review of multiple studies,1 subjects who drank green tea saw numerous health benefits including reduced risk of hypertension, atherosclerosis (hardened arteries), diabetes, lower body fat percentages, osteoporosis,2 and more.3 EGCG may also inhibit cancer cell growth as well as prevent the recurrence of certain cancers.4
Green tea is also high in antioxidants called tea flavonoids, reducing damage to DNA and lipid peroxidation5 (cell damage associated with atherosclerosis, Parkinson's disease, kidney damage, etc.).
Teas (black, green and oolong) also naturally contain fluoride, which protects against cavities and oral bacteria.6
There is also an amino acid in tea called L-theanine. In a few small studies of physiological and psychological stress responses,7 participants were noted to have lower acute stress responses8 when taking L-theanine.
L-theanine is also shown to reduce anxiety by increasing dopamine and GABA levels in the brain.9 One study even suggested that when taken alongside medication for schizophrenia, L-theanine may improve symptoms.10
Ingredients in green tea that may be dangerous
Green tea is a naturally caffeinated tea. As with all sources of caffeine, people with anxiety, irregular blood pressure, insomnia, and heart failure should use caution when consuming caffeine. People sensitive to caffeine may also experience headaches, nausea, vomiting, diarrhea, or excessive urination from drinking green tea.11 Because caffeine is a diuretic, it may increase the effect of diuretic medications, such as Lasix. If you are taking any drugs or have any medical conditions, you should discuss caffeine and its side effects with your healthcare provider.
Minimize or avoid green tea consumption during pregnancy and breastfeeding. As a general rule, drinking green tea on an empty stomach will increase the possibility of gastrointestinal side effects.
There are still also questions as to whether green tea, and other caffeinated beverages, may increase the risk of certain cancers, or if they are instead protective against cancer. Until further research resolves this issue, people who have cancer, a history of cancer, or increased risk of cancer should avoid or reduce their green tea intake and reduce caffeine consumption in general.
Green tea may inhibit the absorption of iron,11 which puts you at risk for anemia. If you are anemic or have a condition that can cause anemia, such as cancer, avoid drinking green tea, or drink it at least one hour after eating a meal.
Specific medications that do not mix well with green tea11 are blood pressure medications, chemotherapy, and cholesterol drugs.
Speaking of drugs, cannabis users should be cautious when mixing their marijuana with caffeine.12 The "wake and bake" mantra is popular among both recreational and medicinal cannabis users, and manufacturers are now coming up with cannabis-infused teas and coffees, or edibles that include caffeine. However, there is preliminary evidence that combining the two may negatively affect memory. And depending on which strain of cannabis you take, you may feel wired and tired at the same time. Until more is learned, use these two psychotropic drugs (marijuana and caffeine) separately from each other.
It's also possible to have an allergic reaction to caffeine as well as to green tea. Symptoms include hives, swelling, trouble breathing, and rapid changes to mood. Seek medical attention immediately if you feel you have an allergic reaction.
The best time to drink matcha green tea
Because green tea contains caffeine, the best time to drink it is earlier in the day when you need better energy or focus, instead of later in the day when it may cause insomnia. To avoid its iron-depleting properties and also prevent stomach upset, I recommend having breakfast, waiting at least one hour, then having one cup of green tea. Start with just one cup if you don't have caffeine often, or aren't sure how you'll react.
I usually have trouble with enough energy to make it through the day. So if my energy starts to flag after lunch, I will make myself a matcha latte and drink it before 3 pm. That's early enough that it will not usually affect my sleep, and keeps me from taking a nap, which will probably keep me awake at bedtime.
How much green tea should I drink?
If you're looking for the health benefits from EGCG,13 one serving of brewed green tea contains approximately 20-40mg of this compound. Matcha powder contains 50-55 mg per serving. Studies show benefits from 100-200 mg of EGCG per day, which is the equivalent of 5-10 cups of brewed tea versus 2-4 cups of matcha.
For L-theanine, testing showed that brewed green tea contains approximately 6.5mg per gram.14 One estimate15 shows the average at about 5 mg, while matcha has 20 mg per gram. With recommendations of 100mg of L-theanine to reap its rewards, you would need to drink 20 cups of green tea or 5 cups of matcha.
But you have to take into account how much caffeine comes in those cups. Brewed green tea and matcha can contain 25-50mg of caffeine or more per serving. It's possible to decaffeinate green tea, but the processes can also remove some of the nutrients. I found a decaffeinated matcha powder, which steeps the leaves before drying them and grinding them into a powder, which they claim removes 98% of the caffeine. Keep in mind that even "decaffeinated" products still have some residual caffeine and any chemical decaffeination process can create other health risks.
To limit the effects of over-caffeination, drink less than 8 cups of green tea per day. Limit to one to two cups per day if you are sensitive to caffeine.
What's the best type of green tea to buy?
Depending on where it's manufactured, green tea has risks from contamination with pesticides and heavy metals, such as lead.16 Chinese green tea is particularly high in lead. The brewed green tea and matcha that is safest for consumption comes from Japan and is preferably organic.
Is green tea better than coffee?
If you're an avid coffee drinker, you may be wondering if you should switch to green tea for health benefits. At this time, the data is inconclusive. I think it's more important to focus on diet overall, rather than expecting a single beverage to make or break your health. However, I will say that drinking lots of caffeine is probably not good for anyone, and neither is adding large amounts of milk, cream, sugar or other sweeteners to your coffee or tea.
If you enjoy having green tea or matcha and don't have any health conditions worsened by drinking it, then I say go for it. However, there are plenty of other healthy things you can do instead if you don't want to consume green tea.