The purpose of this study is to evaluate the effect of daily intake of orange pomace on gastrointestinal function as measured by stool frequency. Additional outcomes will include aspects of digestive health, diet quality, and fasting blood glucose and lipid concentrations. Possible explanations for the mechanism of the pomace will be explored in microbial ecology analyses.
In this randomized, double-blind, controlled trial, healthy adults will be asked to consume daily servings of orange juice containing either 0 g (n=120; control) or 180 g (i.e. 10 g fiber; n=120) of orange pomace for 3 weeks to assess the effect of the pomace on stool frequency. Blood samples will be obtained to assess the effect of the pomace on metabolic markers. Stool samples will be collected for analyses of the effect of the pomace on fecal bacteria known to be associated with health benefits (e.g., bifidobacteria). For exploratory analyses, additional groups will be asked to consume orange juice containing 90 g of pomace (i.e. 5 g fiber; n=40) or orange-flavored, calorie-matched water (n=40); outcomes from the water group will be compared to those of the 0 g pomace juice group to assess any effects of the juice alone, and outcomes from the 90 g pomace group will be compared to those of the 180 g and 0 g groups in microbiota analyses.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
330
16 oz of juice containing 0 g of citrus pomace will be consumed each day for 3 weeks by participants in the group receiving this assignment (group is unknown, double-blinded)
16 oz of juice containing 90 g of citrus pomace will be consumed each day for 3 weeks by participants in the group receiving this assignment (group is unknown, double-blinded).
16 oz of juice containing 180 g of citrus pomace will be consumed each day for 3 weeks by participants in the group receiving this assignment (group is unknown, double-blinded).
University of Florida
Gainesville, Florida, United States
Change in Stool Frequency
The average number of stools per week compared between intervention groups.
Time frame: Weeks -1,0,1,2,3
Change in Stool frequency as a function of stool consistency
The average number of stools per week compared between intervention groups, including Bristol Stool Score category (stool types 1-7 with 1 = hard and 7 = liquid ) as a covariate in the statistical model.
Time frame: Change from Weeks -1,0,1,2,3
Change in Diarrhea symptom score
Measured By Gastrointestinal Symptom Response Scale (GSRS). Questionnaire asks participants about the previous seven days. Scores range from 1 (no discomfort) to 7 (very severe discomfort); lower scores are more desirable.
Time frame: Change from Weeks -1,0,1,2,3
Change in Constipation symptom score
Measured By Gastrointestinal Symptom Response Scale (GSRS). Questionnaire asks participants about the previous seven days. Scores range from 1 (no discomfort) to 7 (very severe discomfort); lower scores are more desirable.
Time frame: Change from Weeks -1,0,1,2,3
Change in Indigestion symptom score
Measured By Gastrointestinal Symptom Response Scale (GSRS). Questionnaire asks participants about the previous seven days. Scores range from 1 (no discomfort) to 7 (very severe discomfort); lower scores are more desirable.
Time frame: Change from Weeks -1,0,1,2,3
Change in Reflux symptom score
Measured By Gastrointestinal Symptom Response Scale (GSRS). Questionnaire asks participants about the previous seven days. Scores range from 1 (no discomfort) to 7 (very severe discomfort); lower scores are more desirable.
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16 oz of a flavored, calorie-matched water beverage will be consumed each day for 3 weeks by participants in the group receiving this assignment (group is unknown, double-blinded).
Time frame: Change from Weeks -1,0,1,2,3
Change in Abdominal pain symptom score
Measured By Gastrointestinal Symptom Response Scale (GSRS). Questionnaire asks participants about the previous seven days. Scores range from 1 (no discomfort) to 7 (very severe discomfort); lower scores are more desirable.
Time frame: Change from Weeks -1,0,1,2,3
Change in Number of bifidobacteria in fecal samples
Bifidobacteria in fecal samples will be quantified via quantitative polymerase chain reaction (qPCR) and compared between groups.
Time frame: Change from Weeks 0 and 3
Change in Fasting blood glucose
Fasting blood glucose determined by Cholestech assay
Time frame: Change from Weeks 0 and 3