Bubble tea may pose potential risks related to heavy metals, intestinal obstruction, kidney stones, obesity, and even mental health. Doctors recommend consuming it in moderation.
Bubble tea shops are now ubiquitous in many cities, directly competing with coffee chains thanks to their colorful, photogenic drinks and countless flavor options.
This beverage originated in Taiwan in the 1980s, typically combining black tea, milk, sugar, and chewy tapioca pearls. The global spread of bubble tea has been remarkable. However, recent studies suggest that this type of drink may need to be viewed with more caution.
From trendy drinks to concerns about heavy metal contamination
An investigation by Consumer Reports in the U.S. found high levels of lead in some commercially available bubble tea products, raising pre-existing concerns about foods made from cassava. The tapioca pearls – the drink's signature 'bubble' – are made from cassava starch. As they grow in the soil, cassava roots are capable of absorbing lead and other heavy metals from their surroundings.
Besides the issue of metal contamination, tapioca pearls can pose other risks. Due to their high density and starch content, consuming large quantities can slow down gastric emptying – a condition called gastroparesis. In more severe cases, it can contribute to intestinal obstruction.
These conditions often lead to nausea, vomiting, and abdominal pain, which are particularly severe for those with already slow digestive systems. Even guar gum – a thickening agent commonly added to bubble tea and generally safe in small amounts – can cause constipation if used regularly.
Impact on the kidneys and risk of kidney stones.
The ingredients in bubble tea can also impact kidney health. In 2023, doctors in Taiwan removed over 300 kidney stones from a 20-year-old woman who habitually drank bubble tea instead of water. Certain components, such as oxalate and high phosphate content, may contribute to stone formation. However, this was considered an extreme case of consumption.
For young children, the risks can be earlier and more direct. Tapioca pearls are a well-known choking hazard, as documented by pediatricians. Adults are not entirely immune either. Singaporean media once reported the case of a 19-year-old woman who died after inhaling three tapioca pearls while forcefully sucking through a clogged straw. Another case was fortunately saved thanks to the timely intervention of bystanders.
The road problem and its long-term consequences.
The sugar content in bubble tea is the most concerning long-term issue. A typical cup of bubble tea can contain 20–50g of sugar, equivalent to or higher than a can of Coca-Cola (approximately 35g). Research in Taiwan shows that by age 9, children who frequently drink bubble tea have a 1.7 times higher risk of permanent tooth decay compared to those who consume it less often.
In California, bubble tea is considered one of the contributing factors to obesity among young people. Its high sugar and fat content increases the risk of type 2 diabetes, obesity, and metabolic disorders. Long-term consumption can also lead to fatty liver disease – a common consequence of products that cause spikes in blood sugar and promote fat accumulation in the liver.
More notably, some recent studies suggest a link between regular bubble tea consumption and mental health issues. Surveys of Chinese children showed that those who drank a lot of bubble tea had higher rates of anxiety and depression. In adults, research on nurses in China also noted a link between regular bubble tea consumption and anxiety, depression, fatigue, burnout at work, and decreased feelings of well-being. However, establishing a cause-and-effect relationship remains complex.
An interesting but perplexing phenomenon in medicine is the appearance of pearls on X-ray images of patients hospitalized for other reasons.
Doctors treating patients with traffic accidents or appendicitis have sometimes discovered dozens of pearl-like objects in the stomach and digestive tract. Due to their high density, they can be clearly visible on diagnostic imaging and are sometimes mistaken for kidney stones or gallstones.
This doesn't mean bubble tea should be banned. However, perhaps it should be considered an occasional "change of pace" rather than a daily habit. If you still want to enjoy it, drinking directly from the cup instead of using a straw can provide better control and reduce the risk of choking.