The proposed study will examine whether eating yogurt every day can improve brain and gut health in children. Prior research suggests that yogurt may support cognitive functions like self-control, but more studies are needed to confirm this. The study will follow 60 children from Central Pennsylvania, ages 7 to 9, who will be randomly assigned to drink either fruit juice (control group) or yogurt smoothies once or twice a day for four weeks. Researchers will compare how different amounts of yogurt affect children's thinking skills (like memory and focus), brain activity, and gut bacteria. These changes will be measured through brain scans, computer-based thinking tasks, surveys, and stool samples. The study will also collect information about children's overall diet. The goal is to find out if yogurt can support healthy brain and gut development and to determine the right amount to include in a child's daily diet. Results will help guide future research on how nutrition supports children's health.
This study is a randomized, between group, dose-response study. Children will be randomly assigned to either receive the control (fruit juice) or a dosage of the experimental yogurt smoothie (1x versus 2x daily) for 4 weeks. Blinding will be established so that researchers do not know which group children are assigned to and families do not know which smoothie is expected to change outcomes. Children will be advised to minimize additional consumption of fermented dairy during the intervention (besides the yogurt provided). Outcomes will be measured at 2 timepoints: immediately before and immediately following the exposure (2 laboratory visits). The visits will take place around 4 weeks apart. In each visit, child participants will undergo a series of tasks, including a Stop Signal Task (SST), a Flanker Task, the Wide Range Assessment of Memory and Learning (WRAML3), the Delis-Kaplan Executive Function System (D-KEFS), the Weschler Abbreviated Scale of Intelligence (WASI-II), and the N-back test. During the N-back test, participants will wear an fNIRS cap to measure and record localized brain activity. Skin carotenoid levels will also be measured using the Veggie Meter. Throughout each visit, the parent participant will complete a series of questionnaires that assess family demographics, home food security, child behavior and temperament, child executive function, family food behaviors, child pubertal development, and beverage consumption frequency. Between the two visits, along with the consumption of the juice or yogurt each day, child participants will complete a weekly food log survey. Parent participants will also complete weekly surveys that assess home food inventory, food and beverage consumption practices, and child behavior. Additionally, parent participants will be asked to collect a fecal sample from their child 1-2 nights before each visit with a provided fecal sample collection kit.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
60
Children consume one yogurt smoothie per day for 4 weeks (93 mL and \~70 kcal).
Children consume two yogurt smoothies per day for 4 weeks (186 mL and \~140 kcal).
Children consume one fruit juice per day for 4 weeks (\~140 kcal, isocaloric with 2 yogurt smoothie).
Metabolic Kitchen and Children's Eating Behavior Lab
State College, Pennsylvania, United States
Cognitive and Brain Responses to Yogurt Smoothie Intake
The investigators will use standardized cognitive tests and functional near-infrared spectroscopy (fNIRS) to assess the effects of nutritional beverages, on executive function and hippocampal-dependent memory in children.
Time frame: Baseline and up to average of 4 weeks
Prefrontal Cortex Activation During Working Memory After Yogurt Smoothie Intake
The investigators will use fNIRS to assess prefrontal cortex activation while children complete a working memory task, comparing the effects of nutritional beverages.
Time frame: Baseline and up to average of 4 weeks
Gut Microbiome and Executive Function Responses
Fecal samples will be collected at multiple time points to analyze changes in the gut microbiome composition and metabolome. These changes will be correlated with improvements in child executive function (EF) and prefrontal cortex (PFC) activation.
Time frame: Baseline and up to average of 4 weeks
Prefrontal Cortex Activation During Working Memory After Yogurt Smoothie Intake
Working memory will be measured using the WRAML3 (Wide Range Assessment of Memory and Learning, Third Edition).
Time frame: Baseline and up to average of 4 weeks
Child anthropometrics
Height and weight will be measured every week using a stadiometer scale. From these, BMI (Body Mass Index) will be calculated and converted to BMI z-score and BMI-for-age and sex percentile
Time frame: Baseline and up to average of 4 weeks
Amount of smoothies leftover
The remaining smoothies will be collected and weighed (gram amount not consumed), and parents will complete a questionnaire to log consumption.
Time frame: Baseline and up to average of 4 weeks
Change in Emotional Symptoms Score (SDQ)
Weekly parent-completed Strengths and Difficulties Questionnaire (SDQ) reporting emotional symptoms subscale, assessing 25 positive and negative behaviors
Time frame: Every week
Dietary intake and quality
Dietary intake will be assessed using two 24-hour dietary recalls per week (one weekday and one weekend day), completed with parental assistance through the ASA24 (Automated Self-Administered 24-hour Dietary Assessment Tool).
Time frame: Assessed weekly
Pubertal stage
Child Tanner stage will be reported by parents at baseline using the Tanner Staging Questionnaire (male or female).
Time frame: Pre-exposure
Measures of carotenoids
The investigators will use a Veggie Meter. It's a device that non-invasively measures the amount of carotenoids in a person's skin, which serves as an indicator of their fruit and vegetable consumption.
Time frame: Baseline and up to average of 4 weeks
Incidence of Gastrointestinal Adverse Events
Parents will complete a daily survey reporting the presence or absence of gastrointestinal symptoms (constipation, diarrhea, abdominal pain, bloating, nausea). Each symptom will be recorded as present/absent, and frequency will be assessed.
Time frame: Every day
Acceptability of the Intervention
Parents will complete a daily survey rating the acceptability of the intervention. Acceptability will be assessed using a Likert scale (e.g., 1 = not acceptable, 5 = highly acceptable)
Time frame: Every day
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