Campus Queries is a series in which Daily Bruin readers and staff present science-related questions for UCLA professors and experts to answer.
Q: Is diet soda bad for our health?
A: Despite increasing associations between artificial sweeteners and negative health implications, the long term consequences of consuming diet sodas remain unclear, experts said.
The difference between artificial sweeteners used in diet sodas and sugars used in regular sodas can be seen on a molecular and physiological level. While sugar follows a simple biological pathway to be broken down and stored for energy in the future, artificial sweeteners bypass this pathway and are expelled by the body in urine, said Dr. Eunice Zhang, a clinical instructor of internal medicine at UCLA Health.
This is why diet sodas don’t contribute anything in terms of calories, which is a unit of energy, she added.
However, this does not mean that diet sodas are healthy.
Artificial sweeteners could be a bigger concern than air pollution or other environmental changes when talking about impacts on a human being’s overall health, said Dr. Zhaoping Li, a professor of clinical medicine and center director and division chief of Clinical Nutrition at UCLA.
Despite this, the majority of consumers do not believe in the dangers of drinking diet sodas, Li added.
“This is because artificial sweeteners may cause different effects on different individuals,” Li said.
One study showed positive associations between people with metabolic syndromes consuming artificial sweeteners and developing diabetes in the future, Zhang said.
Other studies have revealed that artificial sweeteners cannot be properly degraded by the body, which has led to concerns that the buildup of these compounds can alter a body’s metabolism, Li said.
“These artificial sweeteners, in the long run, are actually related to genetic mutations,” Li said. “For example, you may have an increased risk for chronic diseases.”
Increased intake of artificial sweeteners may also cause cancer, Li added.
Researchers have also found that artificial sweeteners in diet soda affect the reward pathways in the brain that allow individuals to experience satisfaction when consuming diet soda, Zhang said.
Continuous diet soda consumption means individuals would require more artificial sweeteners to feel the same degree of gratification, Zhang added. As a result, regular diet soda drinkers often begin to drink multiple cans or even cases of soda per day, she said.
Since artificial sugars are several hundred times sweeter than sugar, there have been theories about changes happening in someone’s palate due to these sweeteners, said Alma Guerrero, an assistant professor in the Department of Pediatrics at UCLA Mattel Children’s Hospital.
These palate changes can result in individuals craving increasingly sweeter foods, she added. Furthermore, Guerrero said she thinks drinking diet soda to promote weight loss may be an ineffective strategy.
“Weight loss is a balance of many things,” she said. “It’s a balance of all foods in moderation and a healthy active lifestyle, so it doesn’t make sense that replacing a drink in your life is going to promote weight loss.”
Nevertheless, the long-term effects of artificial sweeteners still remain unclear. It would take the study of a generation of soda drinkers to finalize a result, Li said.
Therefore, the healthiest drink choice is still water, said Meghan Azad, an adjunct professor of human nutritional sciences at the University of Manitoba, in an emailed statement.
“An occasional soda or diet soda is not going to permanently harm your microbiome or your metabolism,” Azad said. “If you regularly drink soda, using diet soda as a way to wean off could be helpful, but the ultimate goal should be to minimize consumption of all sweetened beverages, regardless of the sweetener used.”