Thanks to Daniel Bowman Simon for pointing me to this one.
The study: Effect of Standardized Grape Powder Consumption on the Gut Microbiome of Healthy Subjects: A Pilot Study. Jieping Yang, et al. Nutrients. 2021 Nov; 13(11): 3965. doi: 10.3390/nu13113965
Methods: Study subjects had to eat 46 grams a day of grape powder (the equivalent of two daily grape servings) for 4 weeks. Their microbiomes and serum cholesterol levels were compared to those observed during a baseline 4-week period.
Conclusions: “In conclusion, grape powder consumption significantly modified the gut microbiome and cholesterol/bile acid metabolism.”
Funding: This research was funded by California Table Grape Commission.
Conflicts of Interest: No potential conflict of interest was reported by the authors.
Comment: The authors see no conflicts of interest but they accepted funding from the Grape Commission for the study. California grape producers issue requests for research proposals to demonstrate the health benefits of grapes using grape powder, so I’m guessing the authors applied for this funding. As I explain in my book, Unsavory Truth, industry influence on research outcome is well documented, but often unrecognized by recipients. Funders typically get what they pay for. Does grape powder duplicate the nutritional benefits of grapes? Hard to say. Are any of these results clinically important? Ditto.