Blueberry Enhances Activity and Cognition Through Increased Vascular Efficiency

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.

Inclusion criteria

• 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

Exclusion criteria

• 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.