Researchers explore influence of grape consumption on gut microbiome

A new human study explored the potential of grapes to modulate the human microbiome. The research, published in Scientific Reports, was carried out by several East coast scientists and funded in part by the California Table Grape Commission.

“Words such as 'prebiotic', 'probiotic', 'synbiotic', 'eubiosis' and 'dysbiosis' are now commonly incorporated in the ordinary lexicon of the lay public and scientific community,” the authors noted.

“Based on human clinical trials, or studies conducted with animal models, results have suggested an array of responses mediated by the grape on atherosclerosis, inflammation, cancer, gastrointestinal health, CNS effects, osteoarthritis, urinary bladder function, and vision."

With this in mind, the researchers conducted an eight-week human study analyzing the impact of grape (Vitis vinifera​ L.) consumption on the microbiome composition as well as urinary and plasma metabolites. 

“In the present study, the human subjects varied by gender and age, but all were deemed to be in good health. It was thereby expected these individuals began the study in a eubiotic state, i.e., with a balance between beneficial and harmful bacteria. Thus, our goal was not geared toward inducing any particular alteration. Our goal was simply to determine if consumption of a common dietary fruit, i.e., the grape, functioned as a prebiotic, probiotic, or antibiotic, or, in fact, led to no major change at all.”

Study details

Over the course of eight weeks, 29 healthy, free-living male and female subjects in their 20s to 50s were studied.

Following a two week period on a controlled dietary regimen, the diet was supplemented for a two-week period in which a well-defined grape surrogate equivalent to three normal servings (2 1/4 cups) were consumed on a daily basis. Lastly, a one month washout period was included where the controlled dietary regimen was continued but grape supplementation was discontinued.

The subjects’ microbiome composition as well as urinary and plasma metabolites were analyzed following two weeks of a restricted diet (day 15), two weeks of a restricted diet with grape consumption (day 30) and four weeks of restricted diet without grape consumption (day 60).

Findings

Changes were seen in the amounts of bacteria detected and in enzyme levels and biological pathways. The analysis of a subgroup of subjects showed unique patterns of microbe distribution.

“Our study showed that grapes actively impact the gut microbiome causing shifts in the intricate interactive networks and thus subtly changing the gut microbiome and the resulting chemicals it produces,” said John Pezzuto, lead author and professor and dean at Western New England University College of Pharmacy and Health Sciences.

“Over the years, we have learned that consumption of grapes has the potential to mediate an amazing cadre of health benefits. Data suggest health improvements in heart, colon, brain, skin, and more. We now know that grapes can change the chemicals in the microbiome. As these chemicals have access to all of our body organs it is logical to conclude that this leads to some of the health benefits that have now been established.”

Source: Scientific Reports​
2023 doi.org/10.1038/s41598-023-34813-5​
“Influence of grape consumption on the human microbiome”
Authors: A. Dave, et al.

Blog Post

Seeing is believing: Supporting the skin microbiome

Delve into the power of the skin microbiome and the rise of probiotic and postbiotic cosmetics for healthier skin.

Read Now