Maximizing the Anti-inflammatory Effects of Strawberry Bioavailability

Overview

Primary objective is to determine if the efficacy of strawberries delivering polyphenols to prevent metabolic inflammation will be influenced by timing of consumption relative to meal intake. Secondary objective is to characterize the relative bioavailability and absorption profile of strawberry polyphenols consumed with meal or at alternatives times around a meal (2 hours before the meal ad 2 hours after the meal). Third objective is to determine the bioavailability/absorption profile of strawberry polyphenols and its relationship with the anti-inflammatory mechanism of action of strawberry constituents.

This study is a randomized, single blinded, 3 -arm, within-subjects, placebo-controlled, design utilizing a multiple sampling, and repeated measures paradigm to evaluate timing influence of consumption of strawberry-anthocyanin-associated acute effect on inflammatory markers. A planned sample size of 18 will be recruited into the study. This study will require one initial screening visit, one pre-study visit, and 3 study visits. The study will take 4-5 weeks per subject to complete. The initial screening visit will provide subject informed consent document and determine subject eligibility through height and weight measurements, vital signs, blood glucose test (finger prick), and completion of a survey related to general eating, health, and exercise habits. If willing and eligible to participate, a 3-day food record (2 weekdays and 1 weekend day) will be instructed at initial screening visit and collected at a pre-study visit to assess subjects' baseline dietary intake pattern. After reviewing baseline food records, subjects will be instructed to avoid any berry products throughout the study and follow a strictly limited polyphenolic diet for 3 days prior to the study visit, while maintaining their usual diet pattern and physical activity. Prior each study visit, a dinner meal will be provided the day before the study visit to control the second meal effect from the food and beverage intake of the night before the study visit. Subject will arrive at the study visits fasted for at least 10 hours, well hydrated and rested. Each study visit will require blood draws throughout the visit. After pre-study procedures (height, weight, waist circumferences, vital sign, and blood glucose measurements) , a registered nurse will place a catheter in subject's arm for the purpose of multiple blood sample collections and take the initial blood draw at fasting. Thereafter, blood sample collection will occur every 1 hour for the next 10 hours. During each study visit, subject will drink one of 3 drinks at fasting (right after fasting blood draw), 2nd drink with the breakfast meal (2 hrs after fasting blood draw) and the 3rd drink at 2 hours after the breakfast meal (4 hrs after fasting blood draw), based on randomization (1 strawberry-containing beverage and 2 identical placebo beverages). The sequences of receiving the beverage treatments at each visit will be randomized to one of three: strawberry-placebo-placebo, placebo-strawberry-placebo, or placebo-placebo-strawberry. Premenopausal female subjects will be studied during the follicular phase of their menstrual cycle because food intake tends to be more stable during the follicular phase (days 1-13) than during the luteal phase (days 14-28) when the rise in progesterone levels decrease satiety often resulting in increased intake.