Adult, Arterial Stiffness, Body Composition, Cognition, Endothelial Function (Reactive Hyperemia), Female, Gut Microbiota, Inflammation, Microvascular Function, Overweight, Oxidative Stress, Prediabetes (Insulin Resistance, Impaired Glucose Tolerance)
Conditions
Keywords
Blueberries, Prediabetes, Insulin Resistance, Functional foods, Dietary intervention, Endothelial function, Vascular function, Cardiovascular health, Metabolic health, Gut microbiota, Cognitive function, Type II diabetes, Microvascular Function, Wild Blueberries
Brief summary
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.
Detailed description
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: * Reduces levels of fasting blood glucose (FBG), insulin, and HOMA-IR (homeostatic model assessment of insulin resistance) and improves lipid profile in women with prediabetes. * Reduces blood pressure and improves endothelial function in women with prediabetes. * Improves cognitive function (verbal memory and executive functions \[inhibition, working memory, cognitive flexibility\]) in women with prediabetes. * Favorably modulates gut microbiota composition in women with prediabetes. * Improves serum markers of oxidative stress and inflammation in women with prediabetes. 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.
Interventions
DIETARY_SUPPLEMENTWild Blueberry
Daily consumption of 22 g of freeze-dried wild blueberry freeze-dried powder for 6 weeks
DIETARY_SUPPLEMENTPlacebo
Daily consumption of 22 g of freeze-dried macronutrient-matched placebo powder for 6 weeks
Sponsors
Georgia State University
Wild Blueberry Association of North America
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
FEMALE
Age
20 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Women aged 20-65 years old * Prediabetes (fasting blood glucose 100-125 mg/dL and/or HbA1c percentage between 5.7-6.4) * Body Mass Index between 25-30 kg/m\^2
Exclusion criteria
* Allergies to berries * Use of insulin, antidiabetic, antibiotics, and anti-inflammatory drugs * Active cancer, gastrointestinal, renal, thyroid, stage 1 \& 2 hypertension and other cardiovascular diseases, neurological diseases, or severe head injury * Smoking * Consumes greater than 2 alcoholic beverages per day * Consumes antioxidant, probiotic, and prebiotic supplements * Pregnant or Lactating * Actively participating in a weight loss program * Currently taking berry supplements or recently participated in another study taking berry supplements
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Ambulatory Blood Pressure | Baseline and 6 weeks | Assessment of whole-day ambulatory blood pressure during daytime and nighttime periods. |
| Blood Glucose | Baseline and 6 weeks | Measurement of fasting blood glucose |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Associative Memory | Baseline and 6 months | Measured using NIH Toolbox Face Name Associative Memory Exam and Face Name Associative Memory Exam Delay tests |
| Attention | Baseline and 6 weeks | Assessed using Wechsler Adult Intelligence Scale - IV and Rey Auditory Verbal Learning Test Trial 1. |
| Problem-Solving | Baseline and 6 weeks | Assessed using NIH Toolbox Visual Reasoning Test |
| Fasting Insulin | Baseline and 6 weeks | — |
| Homeostasis model assessment-insulin resistance (HOMA-R) | Baseline and 6 weeks | Calculated as fasting insulin (mU/mL) x fasting glucose (mg/dL)/405 |
| Blood Lipid Profile | Baseline and 6 weeks | Measurement of blood lipid profile |
| Gut Microbiota Composition | Baseline and 6 weeks | Analysis of stool sample for determination of absolute levels of bacteria and relative species composition |
| Global Cognitive Ability | Screening | Measured using NIH Toolbox Picture Vocabulary test and Oral Reading Recognition |
| Performance Validity | Baseline and 6 weeks | Assessed using Rey 15 |
| Verbal Memory & Recognition | Baseline and 6 weeks | Measured using Rey Auditory Verbal Learning Test with appropriate alternate forms |
| Cognitive Inhibition | Baseline and 6 weeks | Measured using Delis-Kaplan Executive Function System Color Word Interference, and NIH Toolbox Flanker Inhibitory Control and Attention |
| Working Memory | Baseline and 6 weeks | Measured using Digit Span and NIH Toolbox List Sorting |
| Cognitive Flexibility | Baseline and 6 weeks | Assessed using Delis-Kaplan Executive Function System Trails and Verbal Fluency Switching |
| Processing Speed | Baseline and 6 weeks | Measured using NIH Toolbox Pattern Comparison and Oral Symbol Digit tests |
Countries
United States
Contacts
CONTACTRafaela G Feresin, PhD
PRINCIPAL_INVESTIGATORRafaela G Feresin, PhD
Georgia State University
Outcome results
None listed