The results were featured as a poster at the Berry Health Benefits Symposium in Portland, OR, last week, where it won first place in a poster competition.
“We know that the blueberries, or that berries in general are very rich in polyphenols, and we know that they can prevent obesity and metabolic disorders,” Arianne Morissette, one of the co-authors of the study, told NutraIngredients-USA at the symposium.
“We also know that they have an effect on gut microbiota, which we know also has a very important role on the host metabolism.”
The main objective of this project, she added, was to look at which polyphenols in the blueberries that are responsible for the beneficial effects on metabolism, but also how they modulate.
‘We’ve never seen this in the literature before’
The researchers fed mice with a high fat, high sucrose diet to induce obesity. Some of the mice were supplemented with whole blueberry powder, “so it has the polyphenols, the fibers, everything of a complete blueberry,” Morissette explained.
Other groups of mice were supplemented with specific compounds isolated from blueberries—one group received anthocyanins, while the other received proanthocyanidin. This was done so the researchers can better pinpoint which polyphenols do what.
They compared changes in these supplemented mice with a group fed only with chow (control) and a group given the high fat and high sucrose diet without supplementation.
“What we saw was that one the proanthocyanidins groups, they [experienced] reduced body weight gain, and we also saw that these mice were more physically active, which was very interesting because we’ve never seen this in the literature before that polyphenols could increase physical activity,” Morissette said.
Geneviève Pilon, one of the co-authors and lead researchers of the study, suggested that these results may interest the sports nutrition industry. “The PAC (proanthocyanidins), which was linked to increased activity of the mice, it’s new, and for the sports field it is really interesting,” she said.
“We don’t know how it’s working, is it the brain? We don’t know but this is something that we want to explore and could be interesting for product development.”
READ MORE FROM THE SYMPOSIUM: 'Go for the athlete market with berries,' says keynote speaker
Modulating the gut microbiome
The main objective, however, was to observe effects on the gut microbiota of the mice and demonstrate a prebiotic-like action by using fecal microbiota transplantation.
“We transferred the feces of mice that were treated with the blueberry extracts to germ-free mice,” Morissette said.
The researchers observed that anthocyanin and proanthocyanidin mice had reduced insulin secretion, based on oral glucose tolerance test results. When they transferred the fecal microbiota of these two mice groups to sterile mice, they saw the same effects.
“This is really interesting, we were able to transfer insulin resistance via fecal transplantation,” she added.
More data crunching is underway to find associations between bacterial make-ups of the microbiota with different health markers.
“We’re going to try to make associations with the health outcomes that we have seen to look at how the diet will have an effect on the genes and on the function on the microbes, and how this can have an effect on the host metabolism,” Morissette said.
“What’s really interesting with this project is we see not only what is the effect on the host but also can we translate this effect just by transferring the gut microbes into a germ-free animal.”
Source: Berry Health Benefits Symposium 2019, Portland, OR
“Impact of Blueberry Polyphenols on Metabolic Disorders in Diet Induced Obese Mice”
Authors: Arianne Morisette, Camille, Kropp, Stéphanie Dudonnée, Thibault Varin, Vanessa P. Houde, Genevieve Pilon, Yves Desjardins, André Marette