The popularity of drinking green tea continues to rise as more people discover the health benefits this drink has to offer. Although most of the studies supporting the benefits of green tea have been animal studies, it appears likely that many of these health benefits will apply to humans as well. With all of the emphasis on green tea’s health benefits, less attention has been focused on the side effects of drinking green tea. Because green tea is a source of chemicals such as caffeine, polyphenols, and tannins, it’s not always well tolerated. Here are some of the possible side effects from drinking green tea.
Side Effects From Drinking Green Tea: The Caffeine
One possible side effect from drinking green tea arises from the caffeine content. Although green tea has less caffeine than a standard cup of coffee, it’s not caffeine-free. While an eight ounce cup of brewed coffee has around one-hundred milligrams of caffeine, green tea has thirty to sixty milligrams per cup. It’s often recommended that three to five cups be drank per day to maximize the health benefits of green tea. With this amount of tea consumption, caffeine levels can add up quickly, creating problems for those with caffeine sensitivity. Although decaffeinated green teas are available, decaf green tea is lower in catechins which mean the health benefits are reduced. It is possible to reduce the caffeine content significantly by home brewing and discarding the first steeping. The second steeping will have its caffeine content reduced by as much as eighty percent.
Fortunately, the caffeine in green tea may be better tolerated than that in brewed coffee. This is because green tea also contains a compound known as theanine which has a calming effect which offsets some of the nervousness and jitteriness associated with caffeine. In fact another side effect from drinking green tea in some people is excessive sleepiness. These people seem to be particularly susceptible to the sedating effects of theanine. Most average quality green teas sold in the U.S. are relatively low in theanine. Higher quality Japanese green teas are a better source.
Side Effects From Drinking Green Tea: The Tannins
Some people experience mild gastrointestinal upset from drinking green tea. This is most likely due to the tannins found in green tea, although caffeine can also cause nausea in some individuals. The tannins found in tea can reduce absorption of iron in the diet which could increase the risk of iron deficiency if tea is drunk on a frequent basis. For this reason, it’s best not to drink tea with meals. Tannins can reduce the absorption of iron supplements and can interact with certain drugs and prescription medications.
The Bottom Line?
Because of potential side effects from drinking green tea, people with certain medical conditions should avoid drinking it. These include pregnant women; those with uncontrolled hypertension or heart disease; those on blood thinners; and anyone with sleep problems or an anxiety disorder. Because one effect from drinking green tea is increased acid production, it should be avoided by those with a peptic ulcer. Enjoy green tea, but keep the potential side effects in mind.
