Green tea is one of those foods that can seemingly do no wrong. It has an astonishing amount of health benefits—from aiding in weight loss to reducing the risk of cardiovascular disease and even improving your skin. Green tea can make for an impressive addition to your daily routine: It contains approximately 29 mg of caffeine per 8-ounce cup, a substantial decrease when compared to coffee, which typically has around 96 mg. Green tea also contains polyphenols—a plant compound that not only protects against certain cancers and heart disease but also boosts both brain health and digestion—as well as other beneficial antioxidants.
But as with any good thing, too much of it and you might be in for a rude awakening. Some studies have shown that consuming too much green tea can lead to iron deficiency. So how much, exactly, is too much? And what do consumers need to know before brewing up their next cup? We spoke to the experts to find out.
What Happens When You Drink Too Much Green Tea?
Of course, as with anything containing caffeine, drinking too much green tea can also cause side effects such as insomnia, headaches, or stomach upset, especially in those sensitive to caffeine. But drinking excessive amounts of green tea, matcha, or any other drinks that are high in polyphenols (like white tea) can inhibit iron absorption, explains Jessica Strawn, MA, RDN.
"Any food or drink taken in large amounts will cause a nutritional imbalance in the body," she continues.
Cynthia Odogwu, MD, cautions against consuming more than three cups a day if you want to avoid any issues. However, Very Well Health notes that it's very rare for green tea-related anemia or iron deficiency issues to occur, but that certain groups may be more affected than others: "People most affected by this are pregnant people, vegans, and athletes on a restricted diet who tend to have lower iron stores in their bodies." Case studies show this risk is generally associated with very high, prolonged consumption—like more than a quart daily for years.
It's also important to note that green tea may interact with certain medications, such as blood thinners, statin cholesterol-lowering treatments, and beta-blockers. If you take prescription medications, it's smart to check with your healthcare provider before increasing your green tea intake.
What Can You Do To Minimize Risks?
Strawn recommends timing your green tea consumption to help combat its potentially negative side effects. "It is best to drink it between meals rather than with food or as a meal replacement," she tells Delish. "Proper timing helps prevent iron malabsorption, which can contribute to anemia and fatigue."
Nutrition expert Jess Baker, MS, also recommends saving tea for between meals. Additionally, she encourages fans of the drink to wait at least one hour after meals before drinking green tea, add vitamin C sources to iron-rich meals to enhance absorption, and overall, be mindful of your total daily consumption of any single food or drink.
"For those accustomed to drinking green tea throughout the day, substituting alternatives like oolong, rooibos, or black tea—each lower in polyphenols—may help reduce potential effects on iron absorption," suggests Strawn. "However, these teas contain more caffeine, which can present other health concerns if consumed excessively."
Bottom line: Green tea is absolutely safe to drink in moderation. Strawn recommends between one and two cups per day for optimal health. Pair that with consuming proteins high in folic acid and B vitamins, as well as vitamin C-rich fruits and veggies to help prevent anemia and fatigue, she says. Be aware of possible medication interactions—and anyone with conditions linked to anemia like diabetes, hypertension, or chronic kidney disease should make it a priority to have their kidney function assessed regularly.
With these precautions in mind, green tea can be a healthy, enjoyable part of your daily routine. We'll catch you at tea time!
