Wild Blueberries for Gut, Brain, and Heart Health in Adults With High Blood Pressure

Hypertension (HTN), or high blood pressure (BP) is a major modifiable risk factor for heart disease, the leading cause of death worldwide. In the U.S., 121.5 million adults have high BP and only 25% have their BP under control. The 2022 Heart Disease and Stroke Statistics indicated that the incidence of high BP was higher among non-Hispanic Black (NHB) compared to non-Hispanic White (NHW) adults. Berries are rich in fiber and phytochemicals and have several health benefits. A 14-year follow-up of the Nurses' Health Study I and II and the Health Professional Follow-Up Study revealed a significant reduction in the risk of HTN (8%) among individuals in the highest quintile of anthocyanin intake compared to the lowest quintile. Blueberries are rich in fiber and phytochemicals that may be responsible for their health benefits. Studies have shown that daily blueberry consumption improves heart, cognitive, and intestinal health in different populations. Yet, a comprehensive study exploring and comparing the effectiveness of wild blueberries for cardiovascular, intestinal, and cognitive function parameters and their association in NHB and NHW adults with high BP has not been conducted to date.

Thus, the overall objective of this timely study is to determine and compare the effectiveness of a freeze-dried wild blueberry intervention on cardiovascular and gut health in NHB and NHW adults with high BP and assess whether these health benefits are associated with improvements in memory and other important thinking abilities for productivity and quality of life.

Therefore, this 6 - month randomized, placebo-controlled crossover clinical trial aims to assess whether daily consumption of 22 g of freeze-dried wild blueberry powder improves gut, cardiovascular, and cognitive function in NHB and NHW adults with elevated blood pressure and stage 1 hypertension. Investigators hypothesize that daily consumption of wild blueberries will improve cardiovascular parameters, gut dysbiosis, and cognitive function. 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 BP, improves endothelial function, arterial stiffness, and microcirculation.
• Favorably modulates gut microbiota composition.
• Improves cognitive function (verbal memory and executive functions [inhibition, working memory, cognitive flexibility]).
• Improves serum markers of oxidative stress and inflammation.

Additionally, investigators will also explore 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 globally and within each race.

Inclusion criteria

• Individuals 45-65 years of age
• Diagnosis of elevated blood pressure or stage 1 hypertension (systolic blood pressure = 120-139 mmHg and/or diastolic blood pressure = 80-89 mmHg) for at least 6 months
• BMI 25-35 kg/m2 via anthropometric measurements.
• Ability to give consent

Exclusion criteria

• Allergies to berries
• Use of one hypertensive drug for less than three months
• Use of more than one anti-hypertensive or statin drug, insulin, antibiotics, and anti-inflammatory drugs, active cancer, gastrointestinal, renal, cardiovascular, thyroid, and neurological disorders or severe head injury
• Smoking
• Alcohol consumption (>2 drinks/day)
• Consuming antioxidant, probiotic, and prebiotic supplements
• Pregnant or lactating
• Participating in a weight loss program