Sugar-sweetened soda consumption might promote disease independently from its role in obesity, according to UC San Francisco researchers who found in a new study that drinking sugary drinks was associated with cell aging. 
 
 The study revealed that telomeres – the protective units of DNA that cap the ends of chromosomes in cells – were shorter in the white blood cells of survey participants who reported drinking more soda. The findings were reported online Oct. 16 in the American Journal of Public Health. 
 
 The length of telomeres within white blood cells – where it can most easily be measured – has previously been associated with human lifespan. Short telomeres also have been associated with the development of chronic diseases of aging, including heart disease, diabetes and some types of cancer. 
 
 “Regular consumption of sugar-sweetened sodas might influence disease development, not only by straining the body’s metabolic control of sugars, but also through accelerated cellular aging of tissues,” said Elissa Epel, PhD, professor of psychiatry at UCSF and senior author of the study. 
 
 “This is the first demonstration that soda is associated with telomere shortness,” Epel said. “This finding held regardless of age, race, income and education level. Telomere shortening starts long before disease onset. Further, although we only studied adults here, it is possible that soda consumption is associated with telomere shortening in children, as well.” 
 
 The authors cautioned that they only compared telomere length and sugar-sweetened soda consumption for each participant at a single time point, and that an association does not demonstrate causation. Epel is co-leading a new study in which participants will be tracked for weeks in real time to look for effects of sugar-sweetened soda consumption on aspects of cellular aging. Telomere shortening has previously been associated with oxidative damage to tissue, to inflammation, and to insulin resistance. 
 
 Based on the way telomere length shortens on average with chronological age, the UCSF researchers calculated that daily consumption of a 20-ounce soda was equivalent to an average of 4.6 years of telomere shortening. This effect on telomere length is comparable to the effect of smoking, or to the effect of regular exercise in the opposite, anti-aging direction, according to UCSF postdoctoral fellow Cindy Leung, ScD, from the UCSF Center for Health and Community and the lead author of the newly published study. 
 
 Elissa Epel, PhD 
 
 Cindy Leung, ScD 
 
 The average sugar-sweetened soda consumption for all survey participants was 12 ounces. About 21 percent in this nationally representative sample reported drinking at least 20 ounces of sugar-sweetened soda a day. 
 
 “It is critical to understand both dietary factors that may shorten telomeres, as well as dietary factors that may lengthen telomeres,” Leung said. “Here it appeared that the only beverage consumption that had a measurable negative association with telomere length was consumption of sugared soda.” 
 
 The finding adds a new consideration to the list of links that has tied sugary beverages to obesity, metabolic syndrome, type 2 diabetes, and cardiovascular disease, and that has driven legislators and activists in several U.S. jurisdictions to champion ballot initiatives that would tax sugar-sweetened beverage purchases with the goal of discouraging consumption and improving public health. 
 
 The UCSF researchers measured telomeres after obtaining stored DNA from 5,309 participants, ages 20 to 65, with no history of diabetes or cardiovascular disease, who had participated in the nation’s largest ongoing health survey, called the National Health and Nutrition Examination Survey, during the years 1999 through 2002. They found that the amount of sugar-sweetened soda a person consumed was associated with telomere length, as measured in the laboratory of Elizabeth Blackburn, PhD, professor of biochemistry at UCSF and a winner of the 2009 Nobel Prize in Physiology or Medicine for her telomere-related discoveries. 
 
 Additional study authors include, from UCSF, Nancy E. Adler, PhD, professor of psychiatry and director of the Center for Health and Community, and Jue Lin, PhD, an associate researcher with Blackburn’s lab; from UC Berkeley, Barbara A. Laraia, PhD, director of public health nutrition; from the University of Michigan, Belinda Needham, PhD, assistant professor of epidemiology; and from Stanford University, David H. Rehkopf, ScD, assistant professor of medicine. 
 
 Major funding for the study was provided by the National Institutes of Health. Lin is a shareholder of Telomere Diagnostics, Inc. 
 
 UCSF is the nation's leading university exclusively focused on health. Now celebrating the 150th anniversary of its founding as a medical college, UCSF is dedicated to transforming health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy; a graduate division with world-renowned programs in the biological sciences, a preeminent biomedical research enterprise and top-tier hospitals, UCSF Medical Center and UCSF Benioff Children's Hospitals. 

 Nobody would mistake sugary soda for a health food, but a new study published in the American Journal of Public Health just found that a daily soda habit can age your immune cells almost two years. 
 
 Senior study author Elissa Epel, PhD, professor of psychiatry at University of California San Francisco, wanted to look at the mechanisms behind soda’s storied link to conditions like diabetes, heart attack, obesity, and even higher rates of death. She studied telomeres, the caps at the end of chromosomes in every cell in our body, from white blood cells. Shorter telomeres have been linked to health detriments like shorter lifespans and more stress, cardiovascular disease, diabetes and cancer, the study notes. 
 
 Epel and her team analyzed data from 5,309 adults in the National Health and Nutrition Examination Survey (NHANES) from about 14 years ago. They found that people who drank more sugary soda tended to have shorter telomeres. Drinking an 8-ounce daily serving of soda corresponded to 1.9 years of additional aging, and drinking a daily 20-ounce serving was linked to 4.6 more years of aging. The latter, the authors point out, is exactly the same association found between telomere length and smoking. 
 
 Only the sugary, bubbly stuff showed this effect. Epel didn’t see any association between telomere length and diet soda intake. “The extremely high dose of sugar that we can put into our body within seconds by drinking sugared beverages is uniquely toxic to metabolism,” she says. 
 
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 She also didn’t see a significant link between non-carbonated sugary beverages, like fruit juice, which Epel says surprised her. But she thinks the results might be different if the data were more modern. “We think that the jury’s still out on sugared beverages—theoretically they’re just as bad,” she says. “But 14 years ago people were drinking a lot less sugared beverages…they were mostly drinking soda.” At the time of the study, 21% of adults in the study reported consuming 20 ounces or more of sugar-sweetened soda each day, but soda consumption has been on the decline for years. 
 
 Telomere length dwindles naturally as we age, but it may not be an irreversible process. Previous research shows that it’s possible to increase telomere length by as much as 10% over 5 years by stressing less and eating a healthy diet—no soda included. 
 
 Read next: Here’s How to Stop Teens From Drinking Soda 
 
 Write to Mandy Oaklander at mandy.oaklander@time.com.
– Drink a 20-ounce soda daily, and you may be causing your cells to age as much as they would if you smoked, a study suggests. Researchers investigated DNA from 5,309 adults, focusing on telomeres, the caps on the ends of our cells' chromosomes, Time reports. They found that drinking sugary soda was associated with shorter telomeres—and it's known that telomere length may be linked to life span, according to a University of California-San Francisco report. Shorter telomeres also appear to be linked to heart disease, cancer, and diabetes. In the study, a daily 20-ounce soda was associated with an extra 4.6 years of aging—the same figure seen in smokers. About 21% of subjects said they drank that much soda daily, while the average intake was 12 ounces. Researchers also looked at the effects of diet soda and fruit juice on telomeres; while "100% fruit juice was marginally associated with longer telomeres," they write in the American Journal of Public Health, diet sodas and non-carbonated "sugar-sweetened beverages" weren't associated with telomere length. Still, the study points to the dangers of soda beyond its role in obesity. "The extremely high dose of sugar that we can put into our body within seconds by drinking sugared beverages is uniquely toxic to metabolism," says a study author. (If you can't give up soda, here's why you should consider taking 12,000 steps a day.)