People who drink lots of soda or other sugary drinks may have a higher risk of developing rare biliary tract cancers, particularly gallbladder cancer, according to a new study.
The causes of biliary tract and gallbladder tumors are mostly unknown, but surfacing evidence suggests obesity as well as elevated blood sugar levels, a sign of diabetes, may increase the risk of the tumors.
Because sodas and sugary drinks are known to be linked to high blood sugar levels and weight gain, researchers wanted to find out whether these beverages play a role in these types of cancer, lead study author Susanna Larsson of the Karolinska Institute in Sweden said.
Researchers analysed survey data on the eating and drinking habits of more than 70,000 adults and followed them for more than 13 years on average to see whether cancers got diagnosed.
Only about 150 people developed biliary tract or gallbladder cancers during the study period.
There is more than a plausible link, the incidence of biliary and gall bladder cancer was higher among individuals who consumed more sodas and juices.- Dr Margo Denke
Compared with people who avoided sugar-sweetened drinks altogether, individuals who consumed two or more juice drinks or sodas, including artificially sweetened sodas, a day had more than twice the risk of developing gallbladder tumors and 79 percent higher odds of biliary tract cancer, the study found.
"Soda consumption has been inconsistently associated with risk of biliary tract cancer (only one prior study) and other cancers in previous similar studies," Larsson told Reuters.
The current study "is the first study to show a strong link between consumption of sweetened beverages, such as soda, and risk of biliary tract cancer," she added.
The people who drank two or more sodas or sugary beverages a day were more likely to be overweight and eat a higher-calorie diet with more sugar and carbohydrates and less protein and fat.
The increased risk of gallbladder and biliary tract tumors persisted, however, even after researchers adjusted for whether participants were overweight.
Because the study is observational, it does not prove that these beverages cause cancer but merely suggests a link between them.
Even so, "this study suggests that there is more than a plausible link; the incidence of biliary and gallbladder cancer was higher among individuals who consumed more sodas and juices," said Dr. Margo Denke, a former researcher at the University of Texas Southwestern Medical School in Dallas who wasn't involved in the study.
Even though it is not sure to say drinking sodas is a cause of cancer, the easiest way to stay healthy is to quench the thirst with water.