Green tea has been touted for its fat-blocking abilities, its antioxidant properties, and its role in reducing the risk of stroke. But a new report published this week by ConsumerLab.com shows that not all green tea is the same.
Researchers tested 26 types of green tea beverages and supplements and found that some ready-to-drink teas were mostly sugar water. Some of the supplements (which claimed to speed weight loss or help combat cancer) had high levels of caffeine which weren't listed on the labels, and some bagged teas, especially those containing tea grown in China, were contaminated with lead.
"Lead can occur in many botanical products because it is taken up from the ground," Dr. Tod Cooperman, president of ConsumerLab.com, told the New York Times. "The green tea plant is known to absorb lead at a higher rate than other plants from the environment, and lead also can build up on the surface of the leaves."
The researchers found 1.25 micrograms to 2.5 micrograms of lead in tea bags from Lipton and Bigelow, both of which contain tea grown in China. (Luckily for consumers, the lead did not leach into the water when the tea was brewed.) Loose tea leaves from Teavana, which uses tea grown in Japan for their Gyokuro tea, did not contain measurable amounts of lead.
"The majority of the lead is staying with the leaf," Cooperman explained. "If you're brewing it with a tea bag, the tea bag is very effectively filtering out most of the lead by keeping those tea leaves inside the bag. So it’s fine as long as you’re not eating the leaves."
The secret ingredient that makes green tea so powerful is epigallocatechin gallate (EGCG), a potent antioxidant. Researchers measured the levels of EGCG in different types of green tea — leaf tea, ready-made bottled tea, and green tea supplements — and found that the amounts of the beneficial antioxidant varied wildly.
While supplements provided 22 milligrams to 300 milligrams of EGCG per serving (depending on the brand), bottled green-tea beverages contained as little as 4 milligrams of the compound per cup. Honest Tea's Green Tea with Honey promised 190 milligrams of EGCG per serving but only delivered about 114 milligrams, the researchers found, and had as much sugar as half a can of soda. Diet Snapple Green Tea contained almost no EGCG at all.