The study, published this week in the American Journal of Public Health, concludes that sugar-sweetened soda consumption prematurely ages white blood cells.
The University of California, San Francisco researchers say sugary sodas may impact the health of these white blood cells on a scale that is comparable to smoking -- that people who drink soda on a regular basis put themselves at a higher risk for diabetes, heart disease and stroke.
Researchers studied white blood cells in healthy adults, specifically looking at the ends of the study participants' chromosomes, called telomeres.
These telomeres are essential to cell division and naturally get shorter with the passage of time. When a telomere gets too short, its cell dies. Thus, scientists believe longer telomeres mean you're healthier and younger, while shorter telomeres mean you're less healthy and aging faster.
Researchers looked at data from the 1999-2002 National Health and Nutrition Examination Survey, which included information on participants' sugar-sweetened beverage consumption, as well as diet soda and fruit juice consumption.
Controlling for obesity, they found that sugar-sweetened soda consumption was associated with shorter telomeres, but there was no link between telomere length and diet soda. Meanwhile, consumption of 100% fruit juice was associated with slightly longer telomeres.
About one in five adults in the study admitted to drinking a 20-ounce soda each day. This daily consumption could equal 4.6 years of extra aging, according to the study.
The American Heart Association says the best way to both maintain a healthy weight and to decrease the risk of heart disease is to limit added sugar to no more than 150 calories a day for men and 100 calories a day for women. One 12-ounce can of regular soda has 140 to 170 calories and about 40 grams of sugar..