You know that drinking too much soda can give you an unwanted gut, but not all of its effects may be so visible. New research from the University of California at San Francisco suggests that people who guzzle sugary sodas might experience faster aging in their cells.
In the study, people who consumed more soda had shorter telomeres, which are the caps at the end of the DNA-containing chromosomes that protect your genetic data. Telomeres shorten with age, and previous research has linked smaller ones to increased risk of heart problems, diabetes, and certain cancers.
In fact, by analyzing single samples of the participants’ telomeres, the researchers estimated that drinking a 20-ounce (oz.) soda every day would translate to an extra 4.6 years of aging. That’s similar to the effects caused by smoking.
How’d they get there? It might be because sugary sodas cause a rapid influx of liquid calories into your blood stream, which can raise your insulin levels. This spike can increase oxidative stress, insulin resistance, and inflammation—all things known to influence telomere shortening, says study author Cindy Leung, Sc.D.
But when the researchers lumped all sugar-sweetened drinks together—sodas and noncarbonated beverages like fruit drinks or energy drinks—they didn’t find any significant association with shortened telomeres. It’s only when they teased out the fizzy stuff that the link emerged.
That’s weird: Previous studies have shown no difference in how your body responds to sodas and non-bubbly beverages, says Leung. The researchers think that the sugar consumption might only affect your telomeres once it reaches a certain level. Back when the study data was collected 15 years ago, people only consumed an average of 4 oz. of noncarbonated sugary drinks a day, compared to 12 oz. for sugary soda.
“We think if we were to repeat the study again now, we would find a similar association with non-carbonated sugary beverages,” says Leung.
Before you start subtracting years off your life, though, take note: This was an observational study, meaning that it can’t prove cause and effect. Plus, telomere length was based on just one single sample, meaning only one specimen was taken from each participant at one time, so rates of shortening couldn’t be measured. And the beverage consumption data came from people’s 24-hour recall—what they remembered drinking over the last day. This doesn’t necessarily reflect long-term diet patterns.