The Effect of Grape Consumption on Increasing the Good Bacteria in the Human Intestine
Condition: Healthy
Study type: Interventional

Summary: 
      This pilot study will assess the ability of daily consumption of one dose (2 servings) of
      freeze-dried whole table grape powder, made from conventionally grown grapes to alter the
      composition of the bacteria that live in the intestines in healthy subjects. The grape powder
      contains 46g of individually quick frozen (IQF) grapes, which is equivalent to 252g fresh
      fruit. 20 subjects will will consume the beige diet for 4 weeks followed by one dose (two
      servings) of standardized Freeze-Dried Whole Table Grape Powder (46g) daily for 4 weeks. The
      primary objective of this pilot study is to determine changes in the gut microbiome. Stool
      samples will be collected at 4 and 8 weeks for bacterial DNA to determine changes in the
      bacteria that live in the intestines. You will be asked to avoid foods rich in polyphenols
      including dark chocolate and cocoa products, dried herbs, berries, coffee, tea, flaxseeds,
      nuts (chestnut, hazelnut), olive and artichoke for the duration of the study.
    

Detailed description: 
      The bacterial composition of the intestinal microbiome has been linked to the development of
      chronic diseases including obesity, metabolic syndrome, type II diabetes and heart disease.
      Grapes provide a rich source of polyphenols and fiber. It has been demonstrated in animal
      studies that fruits with high polyphenol content and fiber exhibit prebiotic effects leading
      to changes in the gut microbiome, decrease in symptoms of metabolic syndrome, improvement in
      insulin resistance and decrease in intestinal and systemic inflammation. Several human
      intervention studies have also been performed that demonstrated beneficial effects of high
      polyphenol fruits on the intestinal microbiome. No information is available about the effect
      of grape consumption on the gut microbiome. This proposed pilot study will assess the ability
      of consumption of two servings of grapes daily to alter the gut microbiome composition,
      leading to increased bile secretion, increased fecal cholesterol degradation/excretion,
      decreased plasma cholesterol and improved intestinal wellbeing in a free-living population.
      20 subjects will consume the beige diet for 4 weeks followed by one dose (two servings) of
      standardized Freeze-Dried Whole Table Grape Powder (46g) daily for 4 weeks. The primary
      objective of this pilot study is to determine changes in the gut microbiome. Secondary
      outcome will be fecal bile and cholesterol and their metabolites, plasma cholesterol and
      intestinal wellbeing questionnaire at 4 and 8 weeks Stool samples will be collected at 4 and
      8 weeks for sequencing of bacterial DNA to determine changes in the microbiota. Changes in
      fecal bile, cholesterol, and cholesterol metabolites will be analyzed by gas chromatography.
      The objective of the proposed pilot study is to determine whether intake of 2 servings of
      grapes per day will alter the intestinal microflora leading to an increase in intestinal
      cholesterol degradation, decreased plasma cholesterol and increased intestinal wellbeing.
      This project will provide novel preliminary data for future research studies and to develop
      new consumer messages on the gut health benefits of grapes. New consumer information about
      the health benefit of grapes will enhance the The California Table Grape industry domestic
      and export marketing programs and increase consumption of grapes.
    

Intervention name(s): Table Grape Powder; Beige Diet
Intervention type(s): Other; Other
Intervention description(s): Freeze Dried Whole Table Grape Powder; Low Fiber, low polyphenol Diet
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: This will be a two phase intervention study.
Masking: None (Open Label)
Primary purpose: Prevention