While green tea and coffee both have caffeine, coffee has a significantly greater amount per cup. But both have other nutrients in them that have been linked with significant health benefits. However, with any caffeinated beverage, there is a risk of addiction, and certain populations should reduce or avoid caffeine, such as women who are pregnant or nursing.
Effects of Caffeine
Caffeine, the world’s most frequently consumed psychoactive drug, occurs naturally in some foods and beverages like coffee, tea and chocolate. However, caffeine can also be isolated and used in pharmaceuticals, like headache medications. The three effects most commonly associated with caffeine use are increased mental alertness, increased urination and headache reduction. According to PubChem, caffeine promotes these effects in you by relaxing smooth muscle, stimulating cardiac muscle and promoting diuresis.
If you drink a cup of green tea every day, you are receiving a relatively small dose of caffeine. Eight ounces of green tea contain about 35 mg of caffeine, which is about half the amount of caffeine found in regular, black tea. However, this is still more significant than decaf tea, which has between 2 to 10 mg of caffeine per cup. Even iced green tea has caffeine, about 15 mg in a 16 oz. container. But many popular iced teas also have added sugar and calories.
The average cup of coffee has about 100 to 200 mg of caffeine. You would need to drink at least three cups of green tea to get the same amount of caffeine as one cup of coffee. In comparison, a popular anti-sleep aid has about 200 mg of caffeine per tablet. Drinking a cup of decaf coffee provides you with about 2 to 12 mg of caffeine. Interestingly, a 1 oz. shot of espresso has only about 60 to 75mg of caffeine, so a 16 oz. latte has about the same amount of caffeine as 8 oz. of coffee. But a 16 oz. latte can have well over 200 calories from added milk and sugar while coffee with one sugar packet, and some skim milk has about 50 calories.
Comparing Coffee and Tea to Other Caffeine Sources
In general, coffee has more caffeine per 8 oz. than soda and energy drinks, which have about 45 mg and 75 mg of caffeine, respectively. Conversely, green tea has less caffeine than all of these drinks. But coffee and tea can provide you with additional naturally occurring nutrients while most sodas and energy drinks only have added sugars and artificially added vitamins. According to the "British Journal of Nutrition," coffee can provide significant levels of essential nutrients like niacin, magnesium and potassium. In addition, moderate coffee consumption has shown to have a positive impact on antioxidant levels, neurological disorders, metabolic disorders and liver function. According to the "Journal of the American College of Nutrition," the polyphenols, flavonoids and antioxidants naturally found in green tea have been associated with improved body weight control and reduced risk of cardiovascular disease and some forms of cancer.
Potential Caffeine Side Effects
While having a couple of cups of coffee each day is generally considered safe, consuming large amounts of caffeine, more than 500 to 600 mg per day, in either food or pharmaceutical form can lead to overdose symptoms including restlessness, irritation, disturbed sleep cycles and abnormal heart rhythms. In addition, if you are sensitive to caffeine, pregnant or nursing you may want to consider limiting your caffeine intake. In addition, caffeine has been shown to interact with some medications, so speak to your physician about any significant changes in caffeine intake.