Carbonated drinks may raise the risk of esophageal cancer, a usually fatal disease, researchers reported on Monday.
Several studies presented at a meeting of cancer and gastrointestinal experts in New Orleans showed that what people eat and drink could affect a range of cancers.
“This research supports the widespread medical recommendations for healthy eating,” said Dr. Lee Kaplan of Massachusetts General Hospital and Harvard Medical School in Boston.
Rise in esophageal cancer
A team at Tata Memorial Hospital in India found a strong correlation between the rise in per capita consumption of carbonated soft drinks in the past 50 years and a documented increase in rates of esophageal cancer in the United States.
Team members studied U.S. Department of Agriculture data to find that per capita consumption of carbonated drinks rose by more than 450 percent, from 10.8 gallons (49 litres) on average in 1946 to 49.2 gallons (224 litres) in 2000.
And over the past 25 years, the incidence rates of esophageal cancer have risen by more than 570 percent in white American men. Esophageal cancer affected 13,900 U.S. men and women in 2003 -- more than 10,000 men -- and killed almost all of them, according to the American Cancer Society.
The number of esophageal cancer cases clearly followed the rise in intake of carbonated soft drinks, the researchers found.
That could be coincidence, but they also found research that showed a possible biological basis for the effect. Carbonated soft drinks cause the stomach to distend, which in turn causes the gastric reflux associated with esophageal cancer.
The researchers found similar trends worldwide. Countries with per capita annual consumption of more than 20 gallons of fizzy soft drinks also had rising rates of esophageal cancer.
“The surprisingly strong correlation demonstrates the impact of diet patterns on health trends,” Dr. Mohandas Mallath, who led the study, said in a statement.
Caffeine benefits
But another study showed a potential benefit from drinking coffee and other caffeinated beverages.
A team at the National Institute of Diabetes and Digestive and Kidney Disease studied people with a high risk of liver problems and found those who drank more caffeine had fewer liver abnormalities.
They surveyed 5,944 adults at high risk for liver damage because of heavy drinking, hepatitis infection, iron overload or obesity.
The more coffee they drank, the more likely they were to have normal liver function, the researchers found.
“These results warrant further study,” said Dr. James Everhart, who helped lead the study.