A Study of Strawberries and Disease Risk (STRB)
|Nutritional and Metabolic Diseases Inflammation Physiological Responses||Dietary Supplement: Placebo Dietary Supplement: 10G Dietary Supplement: 20G Dietary Supplement: 40G Dietary Supplement: Placebonofiber|
|Study Design:||Allocation: Randomized
Intervention Model: Crossover Assignment
Primary Purpose: Basic Science
|Official Title:||Effect of Strawberry on Oxidative Stress- and Inflammatory-mediated Insulin Resistance (IR) in Humans: Combating a Major Risk Factor for Diabetes and Cardiovascular Disease Through Diet|
- The ability of strawberries to modulate postprandial oxidative stress and inflammation in insulin-resistant men and women in an acute postprandial paradigm [ Time Frame: 6 hour postprandial study over 4-6 week period ]
- The ability of strawberries plus fiber to understand insulin signaling in insulin resistant individuals. [ Time Frame: 6 hours postprandial study over 2-week period ]
|Study Start Date:||September 2010|
|Estimated Study Completion Date:||October 2017|
|Estimated Primary Completion Date:||October 2017 (Final data collection date for primary outcome measure)|
Placebo Comparator: Placebo
Dietary Supplement: Placebo
whole milk shake without strawberry powder served with the high fat/carbohydrate test meal
Other Name: Pbo
Experimental: 10G STRB powder
Dietary Supplement: 10G
whole milk shake with 10g strawberry powder served with the high fat/carbohydrate test meal
Other Name: Dose 1
Experimental: 20G STRB powder
Dietary Supplement: 20G
whole milk shake with 20 strawberry powder served with the high fat/carbohydrate test meal
Other Name: Dose 2
Experimental: 40G STRB powder
Dietary Supplement: 40G
whole milk shake with 40g strawberry powder served with the high fat/carbohydrate test meal
Other Name: Dose 3
Placebo Comparator: PlacebonoFiber
Placebo without fiber
Dietary Supplement: Placebonofiber
Placebo without Fiber
Hide Detailed Description
The main study is a single-center, randomized, cross-over, 4-arm, dose-response, single- blinded, 6-hour postprandial study to evaluate the ability of strawberry powder to block meal-induced oxidative stress and inflammation and concomitantly improve postprandial insulin sensitivity and glucose handling.
A planned sample size of 45 will be recruited into the study. Thirty subjects for the main study and 15 subjects for the complement study. Subjects can participate in both studies and if subjects participate in both studies, there will be a time gap between the main study and the complement study due to the volume of blood permitted to collect within 56 days.
The complement study will be a 2-arm placebo controlled study following the exact same protocol as the main study, but using only one strawberry dose (Dose 3 as in the main study) and comparing the effects relative to a placebo that does not control for fiber.
The main study will take 5- 6 weeks per subject to complete and the complement study will take 1-2 weeks per subject to complete, depending on subject's schedule.
The procedures conducted at the screening visit include blood sampling by finger prick for a fasting blood sugar test and anthropometric measurements (height, weight, and waist circumference), vital sign measurements (blood pressure and heart rate) and completion of a series of questionnaires relating to volunteers' general health and eating habits. Volunteers may be asked to complete an oral glucose/sugar tolerance test (OGTT) at screening. Volunteers will be exempt from the OGTT procedure if other qualifying conditions are present. Briefly, subjects undergoing OGTT will be asked to drink a glucose drink (similar in taste to kool-aid) in the morning after a 10 hour fast. Blood glucose finger pricks will then be done at 1 hour and 2 hours for determination of glucose tolerance. If the OGTT is necessary, additional compensation will be provided.
If qualified, subjects will undergo a 7-day pre-study period during which they will be asked to record their usual diet intake for 3 days, including 2 weekdays and 1 weekend day, EITHER followed by randomization into 1 of 4 treatment beverage sequences for the main study: Placebo (Pbo), Strawberry Dose 1, Strawberry Dose 2 and Strawberry Dose 3, OR followed by randomization into 1 of 2 treatment (Placebo without fiber and Strawberry Dose 3) beverage sequences for the complement study.
We expect it to be very difficult to eliminate or severely restrict polyphenolic diet during the entire study period, therefore subjects will be asked to limit only berry product intake during the study period. However, subjects will be asked to limit all polyphenolic foods in their diet for 3 days prior to each study visit.
All subjects will consume the standard high fat/ carbohydrate meal (known to induce oxidative- and inflammatory- stress) accompanied by 1 of 4 test beverages (whole milk shake with or without strawberry powder) on four separate occasions for the main study OR 1 of 2 test beverages on two separate occasions for the complement study, so that each subject will serve as their own control.
Subjects 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 circumference, blood pressure, blood glucose finger prick) and while fasting, a registered nurse (RN) will place a catheter (flexible tubing) in subjects' arm for the purpose of drawing blood. This catheter will remain only throughout the study day. Approximately 1 tablespoon of blood will be taken at this time. The test meal and strawberry shake will be served and thereafter subjects will have blood draws (1 T each time) at designated time points for the next 6 hours. Each visit will last approximately 7 hours and subjects will be required to remain at the Clinical Nutrition Research Center on the IIT Campus for the duration of the visit. Blood samples will be collected at designated time points during the postprandial period for analysis of metabolic (insulin and glucose homeostasis), oxidative and inflammatory endpoint markers.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01199848
|United States, Illinois|
|Clinical Nutrition Research Center|
|Chicago, Illinois, United States, 60616|
|Principal Investigator:||Indika Edirisinghe, PhD||Institute for Food Safety and Health|
|Principal Investigator:||Britt Burton-Freeman, PhD, MS||Institute for Food Safety and Health|