Effects of Freeze Dried Strawberry Powder Supplementation on Cardiovascular Risk Factors and Gut Microbiome

Dietary interventions designed to promote health by increasing the consumption of particular
health-promoting foods (e.g., strawberries) generally target blood pressure and LDL-C;
however, CVD risk reduction may also be achieved via changes in emerging endpoints such as
the gut microbiome. Previous research suggests that strawberries have the potential to reduce
LDL-C, but it remains unclear whether there is a dose-response relationship. Moreover, few
studies have evaluated effects on vascular health or characterized changes in the gut
microbiome following daily strawberry consumption. Additionally, previous studies have
largely been conducted among Caucasian populations. Given the demographics of the US, it is
important to evaluate effects in study populations that include ethnicities that may have
higher risk of type 2 diabetes and/or other CVD risk factors, such as Hispanics. This study
aims to examine the effects of 4 weeks of supplementation with two doses of freeze dried
strawberry powder (low dose: 13 g/d and high dose: 40 g/d) on: 1) LDL-C and blood pressure;
2) gut microbiome profile; and 3) other CVD and type 2 diabetes risk factors, including
glucose, insulin, and inflammatory markers. Overweight (BMI 25-36 kg/m2) but otherwise
healthy adults with moderately elevated LDL-C (>3.0 mmol/L) and/or prehypertension
(120-159/80-99 mm Hg) will be enrolled. This will optimize the potential for observing
significant benefits on these outcomes. 50 eligible participants will be recruited with the
expectation that at least 40 will complete the study. The placebo-controlled, crossover study
design will allow for a direct comparison of dose-response within the same participant. The
investigators anticipate that the bioactive components of strawberries will reduce LDL-C and
blood pressure, and modify the gut microbiome, with greater changes on the high dose. There
is preliminary evidence that polyphenol-rich foods can modify gut microbiota profiles, but
this would be the first study to characterize the effects of daily strawberry consumption.
The investigators are uniquely placed at the University of Arizona to enroll a larger
percentage of Hispanic participants, who are often under-represented in clinical nutritional
research. Results from the proposed study will improve understanding of how strawberries
might promote health, and could provide further support for the incorporation of whole freeze
dried fruit in dietary guidelines.