New Research Shows Diet Drinks Might Not Be the Sweet Spot
By KECK SCHOOL OF MEDICINE OF USC
Just published in JAMA Network Open,
the study is one of the largest to-date to examine the effects of an artificial
sweetener, also called a nonnutritive sweetener (NNS), on brain activity and
appetite responses in different segments of the population.
Artificial sweeteners: A controversial topic
More than 40 percent of adults in the U.S. currently use NNSs as a calorie-free way to satisfy a sweet tooth, and, in some cases, accomplish weight loss goals.
Despite their prevalence, the health consequences of
artificial sweeteners are still highly debated, with no clear consensus on
their effects on appetite, glucose metabolism, and body weight.
“There is controversy surrounding the use of artificial sweeteners because a lot of people are using them for weight loss,” said Kathleen Page, MD, the study’s corresponding author and an associate professor of medicine at the Keck School of Medicine.
“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.”
To study the effects of NNSs, Page and her colleagues studied 74 participants who, during the course of three different visits, consumed 300 milliliters of a drink sweetened with sucrose (table sugar), a drink sweetened with the NNS sucralose or water as a control.
In the two hours that followed, the researchers measured three things: activation of regions of the brain responsible for appetite and food cravings in response to pictures of high calorie foods like a burger and donut using an imaging technique called functional magnetic resonance imaging (fMRI); levels of glucose (blood sugar), insulin, and other metabolic hormones in the blood; and the amount of food consumed at a snack buffet provided at the end of each session.
The study group comprised an
equal number of male and females who were identified as healthy weight,
overweight, or obese, allowing researchers to explore potential differences
between population groups.
Artificial sweeteners may make certain people feel more hungry
Imaging studies showed increased activity in regions of the
brain responsible for food cravings and appetite in both women and people who
were obese after they consumed sucralose-containing drinks when compared to
drinks containing real sugar.
The study also showed an across-the-board decrease in levels of
hormones that tell the body ‘I feel full’ after participants drank the
sucralose-containing drink compared to the sucrose-containing drink, suggesting
artificially sweetened beverages may not be effective in suppressing hunger.
Finally, after female participants drank the sucralose-containing
drink they ate more at the snack buffet than after they drank the
sucrose-containing drink, whereas snack food intake did not differ for male
participants. Page recommended interpreting these finding with caution, since
all participants fasted overnight before the study and were likely more hungry
than usual.
“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,” Page said. “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.”
Reference: “Obesity and Sex-Related Associations With Differential
Effects of Sucralose vs Sucrose on Appetite and Reward Processing: A Randomized
Crossover Trial” by Alexandra G. Yunker, BA; Jasmin M. Alves, PhD; Shan Luo,
PhD; Brendan Angelo, MS; Alexis DeFendis, BA; Trevor A. Pickering, PhD; John R.
Monterosso, PhD and Kathleen A. Page, MD, 28 September 2021, JAMA Network Open.
DOI:
10.1001/jamanetworkopen.2021.26313
Additional authors of the study include Alexandra Yunker, BA,
Jasmin Alves, PhD, Brendan Angelo, MS, Alexis DeFendis, BA, and Trevor
Pickering, PhD from the Keck School of Medicine of USC; and Shan Luo, PhD, and
John Monterosso, PhD from the Department of Psychology, USC Dornsife.
This work was funded in part by a grant from the National
Institutes of Health (NIH) National Institute of Diabetes and Digestive and
Kidney Diseases (R01DK102794) and the Southern California Clinical and
Translational Science Institute through the NIH grant UL1TR001855.