Blueberry Enhances Activity and Cognition Through Increased Vascular Efficiency
- Conditions
- Arterial StiffnessBlood PressureSedentary LifestyleOverweight and Obesity
- Interventions
- Dietary Supplement: Blueberry Plus Exercise (BB-EX)Dietary Supplement: Blueberry Placebo Plus Exercise (P-EX)
- Registration Number
- NCT04049162
- Lead Sponsor
- Duke University
- Brief Summary
Recent evidence suggests that increased berry intake results in a variety of health benefits, across multiple health domains. This 3-month randomized, double-blind, placebo-controlled trial assess the effects of combining daily blueberry intake with weekly exercise (BB-EX) on cardiovascular function, as well as physical activity and cognitive function, in sedentary older adults (\>60 years). We will compare these effects to the same outcomes with a control group consuming a blueberry placebo (P-EX) at 0, 4, 8 and 12 weeks.
- Detailed Description
A 12-week randomized, double-blind, placebo-controlled physical activity intervention will be administered in sedentary older (\>60 years) women and men randomized to either lyophilized blueberry powder, rehydrated and consumed as a beverage twice daily with meals (BB-EX; n = 25), or an indistinguishable placebo powder, taken in the same manner (placebo control; P-EX; n = 25).
Vascular function (primary outcome), 24-hr ambulatory blood pressure, cognitive performance, and related secondary measures will be assessed at 0 and 12 weeks; berry and nutrient intake and function are assessed every 4 weeks; and physical activity as step counts will be continuously monitored using a mobile device (Garmin). Blood, urine (24-hr), and stool samples will be collected at 0 and 12 weeks and archived for later analysis.
The 12-week study duration is based upon the timing of vascular responses seen in other trials, as well as the minimal time needed to expect a change in cognitive performance in an older adult population. The blueberry dose of 36 grams per day in a split dose consumed with meals is based on (1) a 33% increase in dose over that previously used in a longer (6-month) trial; (2) delivering the most effective dose of blueberry bioactives; and (3) reduced likelihood of any gastrointestinal symptoms.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 84
- Age 60 and older
- Overweight (BMI ≥25 to 35 kg/m2)
- Well-controlled blood pressure (< 150/90 mmHg)
- Able to speak and understand spoken and written English
- Cognitively normal (Mini-Cog score 3-5)
- Able to walk independently
- Social security number (required for compensation)
- Own a smartphone or other mobile device capable of downloading the Garmin Connect app
- Exercise > 150 minutes/week
- Unwillingness or inability to be randomized to any one of two intervention groups without knowing which (double-blind), submit to all study testing, or continuously participate in a randomly assigned diet and exercise intervention for six months.
- Unwilling to restrict consumption of anthocyanin-rich foods
- Unwillingness to abstain from mood altering drugs (including marijuana but excluding CBDs) for 7 days prior to baseline and endpoint testing.
- Self-reported vegetarian or vegan.
- Inability to complete written recording forms including journals of eating and exercise behaviors.
- Inability to complete written and computerized cognitive tasks (presented in English).
- Allergy or intolerance to blueberry or placebo powder ingredients Placebo ingredients include: maltodextrin, fructose, artificial blueberry flavor, natural blueberry flavor, artificial purple color (water, FD&C Red #40, FD&C Blue #1, malic acid, sodium benzoate) citric acid, and artificial red color (water, FD&C Red #40, malic acid, sodium benzoate, silica dioxide).
- Gastrointestinal disorders that influence digestion and absorption of food, e.g., IBD
- History of frequent urinary tract or Clostridium difficile infections
- Presence of unstable, acutely symptomatic, or life-limiting illness.
- Regular use of medication that interferes with the measurement of study outcomes as determined by the study physician.
- Unstable use of medications, other than statins, for conditions associated with metabolic syndrome (hypertension, diabetes, dyslipidemia) during the prior 6 months or during the study.
- Antibiotic use in the last 3 months.
- Cigarette smoking, chewing, or use of nicotine replacement products in the past 3 months or during the course of the study.
- Colonoscopy in last 2 months.
- History of stomach or bowel resection (other than appendectomy), gastric bypass or other bariatric weight loss procedure effecting absorption.
- History of significant weight instability (defined as > 10 pounds weight gain or loss over one month prior to study participation).
- History of cancer treatment (other than melanoma skin cancer) and not "cancer-free" for at least 1 year.
- History of anti-hormonal therapy (eg., for breast or prostate cancer) within the last 6 months.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Blueberry Plus Exercise (BB-EX) Blueberry Plus Exercise (BB-EX) BB-Ex participants will consume lyophilized blueberry powder, mixed with water (18 grams, equivalent to 3/4ths cup of blueberries) with 2 daily meals (36 g/d blueberry powder total; approx. 1.5 servings/d) Blueberry Placebo Plus Exercise (P-EX) Blueberry Placebo Plus Exercise (P-EX) Participants randomized to P-EX treatment will consume an indistinguishable placebo powder, matched for color, flavor, consistency, and caloric content, in the same manner.
- Primary Outcome Measures
Name Time Method Change from baseline in pulse wave velocity at 12 weeks 0 to 12 weeks Change in carotid-femoral pulse wave velocity will be assessed using applanation tonometry, (SphygmoCor Pulse Wave Velocity System)
- Secondary Outcome Measures
Name Time Method Change from baseline in ambulatory blood Pressure at 12 weeks 0 to 12 weeks Change in ambulatory blood pressure will be measured using an Ambulatory BP Monitor, with readings taken every 30 min. during the day and 60 min. at night, over a 24-hour period.
Change from baseline in macronutrient intake at 4, 8 and 12 weeks 0 to 12 weeks (0, 4, 8 and 12 weeks) Total calories will be measured using 3-day food records (participants record everything they eat and drink for three days)
Change from baseline in total calories at 4, 8 and 12 weeks 0 to 12 weeks (0, 4, 8 and 12 weeks) Total calories will be measured using 3-day food records (participants record everything they eat and drink for three days)
Change from baseline in micronutrient intake at 4, 8 and 12 weeks 0 to 12 weeks (0, 4, 8 and 12 weeks) Total calories will be measured using 3-day food records (participants record everything they eat and drink for three days)
Change from baseline in physical activity at 12 weeks 0 to 12 weeks Change in physical activity will be measured using a commercial activity monitor, which will be worn 24 hr/d to capture total daily steps as the measure of physical activity.
Change from baseline aerobic endurance at 4, 8, and 12 weeks 0 to 12 weeks (0, 4, 8 and 12 weeks) Change in aerobic endurance will be determined by a 6-minute walk where subjects walk as many laps as possible in 6 minutes between cones placed 100 feet apart.
Change from baseline in cognitive flexibility at 12 weeks 0 to 12 weeks Change in cognitive performance will be assessed using a computerized task-switching test in which participants predictably alternate between two discrimination tasks.
Change from baseline hand grip strength at 4, 8 and 12 weeks 0 to 12 weeks (0, 4, 8 and 12 weeks) Change in maximal upper body strength will be determined using hydraulic isometric hand dynamometer.
Trial Locations
- Locations (1)
Duke University Medical Center
🇺🇸Durham, North Carolina, United States