An interventional study of Wild Blueberry and Placebo in Prediabetes (Insulin Resistance, Impaired Glucose Tolerance), Female and Adult, sponsored by Georgia State University. Recruiting at 1 site in United States. Open to female participants aged 20 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-09-02.
Sponsored by Georgia State University · Not applicable, Interventional, and Basic science
The goal of this clinical trial is to determine the effectiveness of using a freeze-dried wild blueberry powder on cardiometabolic health, cognitive function, and gut microbiota composition in adult women with prediabetes.
In the U.S., 35.3 million adults have type 2 diabetes mellitus (T2DM) and 96 million have prediabetes. Eight out of 10 people with T2DM die from cardiovascular disease. People with T2DM also have a 50% higher risk of developing dementia compared to healthy counterparts. Further, studies show that gut microbes play a major role in the development of T2DM. Prevention and treatment of T2DM focus on lifestyle changes including dietary modifications such as increased consumption of deep-colored fruits like berries. Blueberries are rich in fiber and phytochemicals and have several health benefits. We and others have shown that blueberry intake improves heart health in healthy men, hypertensive postmenopausal women, and men and women with metabolic syndrome. Yet, a comprehensive study in women with prediabetes that measures changes in cognitive performance and the underlying heart and gut health has not been conducted to date. Thus, the overall objective of this study is to investigate and bring forth evidence that wild blueberries improve gut, cardiometabolic, and cognitive function in women with prediabetes.
Therefore, this pilot six-week randomized, placebo-controlled parallel-arm clinical trial aims to investigate whether daily consumption of 22 g of freeze-dried wild blueberry powder improves gut, cardiometabolic, and cognitive function in women with prediabetes. Investigators hypothesize that daily consumption of wild blueberries will improve cardiometabolic parameters, gut dysbiosis, and cognitive impairments in our study population. To test these hypotheses, the following specific aims are proposed. To investigate whether daily consumption of 22 g of freeze-dried wild blueberry powder:
Additionally, whether changes in the gut microbiota are associated with changes in cardiometabolic and cognitive function outcomes and whether changes in cardiometabolic outcomes are associated with changes in cognitive function parameters will be explored.
918 studies on the registry are indexed under Prediabetic State; 232 are open to participants now.
This study's planned enrollment of 30 is below the median of 62 across 762 interventional studies indexed under Prediabetic State.
Browse Prediabetic State studies →Georgia State University is the lead sponsor of 56 studies on the registry; 14 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
22 g of freeze-dried wild blueberry freeze-dried powder per day
Dietary Supplement: Wild Blueberry
22 g of freeze-dried macronutrient-matched placebo powder per day
Dietary Supplement: Placebo
Daily consumption of 22 g of freeze-dried wild blueberry freeze-dried powder for 6 weeks
Daily consumption of 22 g of freeze-dried macronutrient-matched placebo powder for 6 weeks
Blood Glucose
Measurement of fasting blood glucose
Time frame: Baseline and 6 weeks
Ambulatory Blood Pressure
Assessment of whole-day ambulatory blood pressure during daytime and nighttime periods.
Time frame: Baseline and 6 weeks
Fasting Insulin
Time frame: Baseline and 6 weeks
Homeostasis model assessment-insulin resistance (HOMA-R)
Calculated as fasting insulin (mU/mL) x fasting glucose (mg/dL)/405
Time frame: Baseline and 6 weeks
Blood Lipid Profile
Measurement of blood lipid profile
Time frame: Baseline and 6 weeks
Gut Microbiota Composition
Analysis of stool sample for determination of absolute levels of bacteria and relative species composition
Time frame: Baseline and 6 weeks
Global Cognitive Ability
Measured using NIH Toolbox Picture Vocabulary test and Oral Reading Recognition
Time frame: Screening
Performance Validity
Assessed using Rey 15
Time frame: Baseline and 6 weeks
Verbal Memory & Recognition
Measured using Rey Auditory Verbal Learning Test with appropriate alternate forms
Time frame: Baseline and 6 weeks
Cognitive Inhibition
Measured using Delis-Kaplan Executive Function System Color Word Interference, and NIH Toolbox Flanker Inhibitory Control and Attention
Time frame: Baseline and 6 weeks
Cognitive Flexibility
Assessed using Delis-Kaplan Executive Function System Trails and Verbal Fluency Switching
Time frame: Baseline and 6 weeks
Working Memory
Measured using Digit Span and NIH Toolbox List Sorting
Time frame: Baseline and 6 weeks
Processing Speed
Measured using NIH Toolbox Pattern Comparison and Oral Symbol Digit tests
Time frame: Baseline and 6 weeks
Associative Memory
Measured using NIH Toolbox Face Name Associative Memory Exam and Face Name Associative Memory Exam Delay tests
Time frame: Baseline and 6 months
Attention
Assessed using Wechsler Adult Intelligence Scale - IV and Rey Auditory Verbal Learning Test Trial 1.
Time frame: Baseline and 6 weeks
Problem-Solving
Assessed using NIH Toolbox Visual Reasoning Test
Time frame: Baseline and 6 weeks
Reactive Hyperemia Index
Assessment of endothelial function in response to increased shear stress using EndoPAT2000
Time frame: Baseline and 6 weeks
Pulse Wave Velocity
Arterial Stiffness will be assessed by pulse wave velocity using SphygmCor
Time frame: Baseline and 6 weeks
Percent Maximal Microvascular Blood Flow
Micro-vessel blood flow in response to local heating stimulus will be assessed using a Laser Doppler
Time frame: Baseline and 6 weeks
Circulating Markers of Inflammation and Oxidative Stress
Measurement of concentrations of circulating markers of inflammation such as CRP and oxidative stress such as TBARS in blood plasma and serum samples.
Time frame: Baseline and 6 weeks
Urinary Polyphenolic Metabolites
24-hour urine collection samples will be assessed for polyphenol metabolites
Time frame: Baseline and 6 weeks
Body Fat
DEXA will be used to assess body fat.
Time frame: Baseline and 6 weeks
Plan to share: No
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