Boba tea (also called pearl tea, or bubble tea) is a sweet drink that combines milk, flavored tea and tapioca pearls that are sucked up through an extra large straw and chewed. The pearls have a soft, chewy consistency similar to that of gummy candy. The tea was introduced in Taiwan in the 1980s, quickly spread through Southeast Asia and more recently has become very popular among young people in the U.S. and in Europe. The tapioca pearls usually are black and are made from cassava starch, sweet potato and brown sugar. Sometimes, white tapioca pearls are used - these are made from cassava starch, caramel and chamomile root and have a different flavor.
The total calorie counts for the teas depend on how much you’re served, but in general, these are high-calorie, high-fat drinks. I’ve seen counts as high as 440 calories for a 16-ounce tea, with more than 200 of those calories from fat.
The latest news about boba tea comes from Germany, where researchers at University Hospital, Aachen found that the tapioca pearls in the Boba tea beverages they tested contain traces of polychlorinated biphenyls (PCBs) such as styrene, acetophenone and brominated compounds. These chemicals are known to have adverse health effects in humans and animals and are regarded as potential carcinogens. They were banned in the United States in 1979, but were widely used earlier as plasticizers in paints, plastics, rubber products and many other industrial applications. The compounds don't readily break down, so those used in the past are still being released into the environment.
In addition to the health risks associated with PCBs, in August, 2012, the German Federal Institute for Risk Assessment warned that the tapioca pearls can pose a risk of choking in children under age four when sucked up through a straw.
We don’t know the exact origin of the tapioca pearls tested by the German researchers, who have said only that they came from Taiwan. To avoid the PCBs you could look for a recipe on line and try making your own pearls. Until we know more about the extent of contamination of tapioca pearls, it’s probably a good idea to cut back on consumption of these teas or to avoid them entirely.
Andrew Weil, M.D.