In a new study led by the University of Southern California’s (USC) Keck School of Medicine and published in JAMA Network Open, scientists studied the effects of an artificial sweetener – or a nonnutritive sweetener (NNS) – both on brain activity and appetite responses in different groups of the population.
Seventy-four adult participants, including 43 women, completed the study from March 2020 to March 2021, including an equal number of males and females who identified as healthy weight, overweight or obese.
During the course of three separate morning visits to USC’s Dornsife Cognitive Neuroimaging Center, the participants consumed 300 milliliters of a drink sweetened with sucrose (nutritive sugar), a drink sweetened with the NNS sucralose or water as a control.
Researchers then spent two hours measuring the activation of regions of the brain responsible for appetite and food cravings in response to pictures of high-calorie foods using an imaging technique called functional magnetic resonance imaging (fMRI) in addition to glucose levels, insulin levels and other metabolic hormones in the blood and the amount of food eaten at a snack buffet at the end of each session, according to an accompanying release.
“Blood was sampled at baseline and 10, 35, and 120 minutes after participants received a drink containing sucrose, sucralose, or water to measure plasma glucose, insulin, glucagon-like peptide (7-36), acyl-ghrelin, total peptide YY, and leptin. Participants were then presented with an ad libitum meal. Participants were right-handed, nonsmokers, weight-stable for at least three months before the study visits, nondieters, not taking medication, and with no history of eating disorders, illicit drug use, or medical diagnoses,” the group said in the study’s abstract.
The imaging studies revealed increased activity in regions of the brain responsible for food cravings and appetite after women and obese people consumed sucralose-containing drinks, compared to drinks containing real sugar.
There was also a decreased level in hormones leading the participant to feel full after they drank the sucralose-containing drink compared to the sucrose-containing drink.
Lastly, female participants who drank the sucralose-containing drink ate more at the snack buffet than after they drank the sucrose-containing drink.
Food intake did not differ for male participants, and more than 40% of U.S. adults currently use NNSs as a calorie-free option to help in weight loss and still get a sweet treat.
“Our study starts to provide context for the mixed results from previous studies when it comes to the neural and behavioral effects of artificial sweeteners,” Dr. Kathleen Page, the study’s corresponding author and an associate professor of medicine at the Keck School of Medicine, said in a statement. “By studying different groups we were able to show that females and people with obesity may be more sensitive to artificial sweeteners. For these groups, drinking artificially sweetened drinks may trick the brain into feeling hungry, which may in turn result in more calories being consumed.”
Page recommended interpreting findings with caution because all participants fasted for 12 hours overnight ahead of the study.
In addition, she noted that the health consequences of artificial sweeteners remain highly debated.
“There is controversy surrounding the use of artificial sweeteners because a lot of people are using them for weight loss,” Page said. “While some studies suggest they may be helpful, others show they may be contributing to weight gain, type 2 diabetes and other metabolic disorders. Our study looked at different population groups to tease out some of the reasons behind those conflicting results.”
The U.S. Food and Drug Administration (FDA) currently lists six high-intensity sweeteners as FDA-approved as food additives, including saccharin, aspartame, acesulfame potassium (Ace-K), sucralose, neotame and advantame.
The U.S. Centers for Disease Control and Prevention warns that those who often drink sugar-sweetened beverages are more likely to face health problems, including weight gain, obesity, Type 2 diabetes, heart disease, kidney diseases, nonalcoholic liver disease, cavities and gout.