Regularly drinking high levels of sugar-sweetened soda could lead to the premature aging of immune cells, leaving the body vulnerable to chronic diseases in a similar manner to the effects of smoking, according to research.
In a new study, scientists from the University of California-San Francisco (UCSF) observed that survey participants who drank larger amounts of sugary soda tended to have shorter telomeres - protective DNA that caps the ends of cell chromosomes - in their white blood cells. Their findings are published in the American Journal of Public Health.
Previous research has associated the length of telomeres within white blood cells with the human lifespan. In addition, short telomeres have been linked with tissue damage, inflammation and insulin resistance, along with chronic diseases such as coronary heart disease and diabetes that are associated with aging.
"Regular consumption of sugar-sweetened sodas might influence disease development," says Prof. Elissa Epel, senior author of the study. "Not only by straining the body's metabolic control of sugars, but also through accelerated cellular aging of tissues."
Every day, according to the Harvard School of Public Health in Boston, MA, around 50% of Americans consume sugary drinks. About 1 in 4 consume at least 200 calories from sugary soda, and 5% consume at least 567 calories from them - equivalent to four cans of soda.
Sugary drinks have long been regarded as a major contributor to rising rates of obesity in the US. Many health experts, legislators and activists have been looking at ways to reduce public consumption of these beverages, and these findings could add further fuel to this fire.
Additional biological aging
The researchers assessed 5,309 participants of the National Health and Nutrition Examination Survey (NHANES) who took part from 1999 to 2002. Participants were aged 20 to 65 years old, with no prior history of cardiovascular disease or diabetes.
The average sugar-sweetened soda consumption for the participants was 12 ounces, with 21% of the participants reporting drinking at least 20 ounces of sugary soda every day.
Stored DNA was obtained for the participants, and their telomeres were measured in the laboratory of Prof. Elizabeth Blackburn - previously a winner of the Nobel Prize in Physiology or Medicine for her research into telomeres - at UCSF.
The researchers found that the amount of sugar-sweetened soda the participants consumed was associated with the length of their telomeres. They calculated that consuming 20 ounces of soda every day was associated with around 4.6 years of additional biological aging, based on how telomere length shortens with chronological aging.
According to lead author Cindy Leung, the effect that sugar-sweetened soda appeared to have on telomere length was comparable to the same effect that smoking has on them. Regular exercise has been observed to have an opposite anti-aging effect.
Soda consumption 'could have same effect on children'
Prof. Epel says that the study is the first demonstration that soda is associated with telomere shortness, and that the findings from their nationally representative sample are strong:
"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."
"It is critical to understand both dietary factors that may shorten telomeres, as well as dietary factors that may lengthen telomeres," adds Leung. "Here it appeared that the only beverage consumption that had a measurable negative association with telomere length was consumption of sugared soda."
The authors acknowledge that their findings were limited by only comparing telomere length and soda consumption at one particular point in time. In addition, the association observed does not confirm causation.
Future research will address these limitations; Prof. Epel will be co-leading a new study tracking participants for weeks in real-time, assessing what the effects of sugar-sweetened soda consumption are on the aging of cells.
Previously, Medical News Today reported on a study analyzing the potential impact that additional taxation or an advertising ban for sugar-sweetened drinks could have on obesity in adolescents. Researchers concluded that a soda tax would be "the best option" for reducing childhood obesity.