Drinking Soda May Increase Esophageal Cancer Risk

How Carbonated Beverages Can Cause Heartburn and, Possibly, Cancer

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Drinking soda isn't just associated with weight gain, but also the increase of esophageal cancer in the U.S.  A strong correlation between the rise in carbonated soft drinks consumption in the past 20 years and the increasing rates of cancer in the United States was found by researchers at Tata Memorial Hospital in India.

Consumption of carbonated soft drinks rose by more than 450 percent, from 10.8 gallons per year in 1946 to 49.2 gallons per year in 2000.

At the same time, during the last 25 years, rates of esophageal cancer have increased more than 570-percent among American white males.

How Soda Causes Heartburn, and Possibly Cancer

There is a biological link between soft drink consumption and increased gastric pressure, which can result in increased reflux. And recurring acid reflux is the most important risk factor for adenocarcinoma — a type of cancer that forms in mucus-secreting glands — in the esophagus.

Carbonated soft drinks are related to gastric distension, which can trigger reflux. "If you drink a quarter of a liter of water, your stomach distends by a quarter of a liter, but if it's a carbonated drink, your stomach may distend to maybe half a liter," says study co-author Mohandas Mallath, MBBS, MD, head of the digestive diseases department at Tata Memorial Hospital. "This causes reflux — the acid of the stomach is thrown back into the food pipe." 

However, it may not just be the carbonation of the soda that causes the reflux. Most sodas contain simple sugars and our bodies use microorganisms to consume the sugars and change them into a form that our bodies can absorb. This process can cause, you guessed it, a gas that can push the stomach contents up into the esophagus.

Studies show the consumption of one can of soda a day corresponds to 53.5 minutes of elevated acid levels in the stomach. When this is figured on an annual basis, that's about 53 gallons of soda per year, with 32,100 more minutes of elevated acid reflux per year, and the esophagus' exposure to it. 

To Drink Soda or Not

This increase in esophageal exposure to acid as the consumption of carbonated soft drinks increases could explain the rising incidences of cancer. "It is a very significant correlation, which demonstrates the impact of diet patterns on health trends," Dr. Mallath said.

But a correlation or an association does not mean that drinking carbonated beverages causes cancer. 

For this GERD sufferer, this is definitely food for thought. Though a recent upper endoscopy exam showed no damage to my esophagus, I feel it's wise to take precautions. As I have with the rest of my diet, I try to avoid foods and beverages that can increase my risk of acid reflux. Carbonated beverages are only a small part of my daily fluid intake. While further study will be needed to show whether there is a definite cause-and-effect relationship between soda drinking and esophageal cancer, it may be better err on side of caution until further information is available.