In a recent study published in Nutrients, researchers evaluated the potential cognitive and metabolic health benefits of replacing sugar-sweetened beverage (SSB) consumption with non-nutritive sweetened beverages among young adults.
SSB intake, including the consumption of carbonated energy drinks, soft drinks, iced teas and coffees, and flavored milk and juices, forms the main dietary source of elevated sugar consumption, increasing cardiometabolic disease risks.
In addition, animal and human studies have reported that SSB intake can lead to cognitive impairments, especially concerning hippocampal functions and spatial memory; however, eliminating SSBs from diets could ameliorate the effects.
About the study
In the present unblinded, three-group parallel design study, researchers investigated whether SSB intake-reducing interventions such as consuming low-calorie or unsweetened beverages could enhance hippocampus-associated cognitive function in humans over 12 weeks (4.50 liters).
Young, healthy adults aged 18 to 35.0 years with BMI values between 17.5 and 30.0 who consumed more than two liters of SSBs weekly were recruited for the study between April 2016 and September 2018.
The team assessed the effects of a 12.0-week intervention wherein individuals [mean values for age (years) and body mass index (BMI) were 23 and 23.20, respectively] who regularly drank SSBs were instructed to switch to either artificially-sweetened or non-nutritive ‘diet’ beverages (Diet group, 28 individuals) or water (Water group, 25 individuals) or continue to consume SSBs such as carbonated soft drinks (Sugar group, 27 individuals).
The primary study outcomes were short-term changes in verbal memory and the waist circumference to height ratio (WC:H), assessed at study initiation, week 6.0 and week 12.0 of the intervention period, and during 12.0 weeks of follow-up post-intervention. Cognitive changes were evaluated using the logical memory (LM) test.
Secondary outcomes included obesity, BMI, serological lipid, uric acid, and glucose levels, blood pressure, and affective measures. In addition, the team investigated whether switching to unsweetened or low-calorie beverages altered the preference for sugary beverages by assessing changes in liking for five concentrations (1.50%, 3.0%, 6.0%, 12.0%, and 24.0%) of sucrose solutions following the oral glucose tolerance test (OGTT) and study intervention. Sweeteners such as sucralose, aspartame, and acesulfame-K were added to the diet drinks.
Body fat was determined by bioelectrical impedance analysis (BIA), and verbal fluency was assessed using the Controlled Oral Word Association Test (COWAT) test. SSB consumption and high-fat sugary food intake were estimated using the Brief Beverage Intake Questionnaire (BEVQ) and the Dietary Fat and Free Sugar-Short Questionnaire (DFSQ), respectively, which were filled out by the participants. In addition, the participants completed the Revised Barratt Impulsivity Scale-Short Form (BIS-11) and the Depression, Anxiety, and Stress Scale (DASS-21).
Results and discussion
Of the 118 individuals allocated to the study groups, 97 completed the 12.0-week intervention, among whom 39 were female, and 87 returned for follow-up evaluations 12.0 weeks post-intervention. Among the study participants, the mean documented SSB intake at baseline was 6.70 liters weekly.
The team observed no statistically significant group differences between the study groups in the primary study outcomes of metabolic well-being (WC:H) and memory (hippocampal-dependent LM recalling), as well as the secondary study outcomes, including impulsivity, verbal fluency, obesity, glucose tolerance, or affect.
However, the liking for strong sucrose solutions (12% and 24%) was significantly reduced among individuals who switched to water. Regular evaluation of SSB consumption using the BEVQ questionnaires and compliance assessments at weekly drink sessions indicated that the 12.0-week study intervention was tolerable and was adhered to by the majority of participants.
Consistently elevated percentages for delayed-type recall were observed, with individuals reciting 90.0% of the data recalled by them during the acute recall test, in accordance with prior studies, but raising the probability of ceiling effects and lowering the ability to determine the influence of the study intervention. Further research must be conducted, incorporating more challenging types of test batteries.
The team administered the COWAT and the LM (immediate and delayed) tests 30.0 to 60.0 minutes after consuming glucose for the OGTT. Previous studies have reported that acute intake of glucose can improve acute recall of verbal memory, raising the probability of acute test performance facilitation and obscuring group-based differences due to prior intake of glucose.
BEVQ data indicated that the average SSB consumption was 3.0 liters weekly in the follow-up period, indicating that the water recipients and diet drink recipients resumed consuming SSBs post-intervention, whereas the SSB recipients decreased their SSB consumption in relation to the interventional intake (4.50 liters weekly).
Nevertheless, among all three groups, the data represented a significant SSB reduction in relation to pre-intervention estimates of 6.0 liters weekly. In addition, DFSQ data indicated a statistically significant decrease in self-documented frequencies of sugar and fat intake at week 6.0 and week 12 of the intervention, with greater declines in the water recipients and diet drink recipients, indicating that the individuals also decreased their intake of sugar-coated solid food items.
Overall, the study findings showed no significant short-term impact of replacing SSBs with artificially-sweetened beverages or water on the metabolic and/or cognitive health of the youth. The increased consumption of Western diets likely obscured the potential health benefits of reducing SSB consumption over 12 weeks.