Blueberry Enhances Activity and Cognition Through Increased Vascular Efficiency

Effects of Blueberry Consumption on Vascular Function, Physical Activity, and Cognition in Sedentary Older Adults

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.

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.