A daily drink of juice containing wild blueberry powder may boost select bifidobacteria strains in the gut with the potential to influence immune health, says a new study with human volunteers.
Six weeks of consuming a glass of the blueberry drink were associated with significant increases in Bifidobacterium longum subsp. Infantis, which could be considered a health benefit because of the strain’s immunomodulatory abilities, report researchers from the Università degli Studi di Milano (Italy) and the University of Maine (USA).
“In this context, we suggest blueberries as a source of prebiotic (bifidogenic) molecules (possibly, fibers and glycosylated anthocyanins) that can selectively increase certain populations of bifidobacteria (viz., B. longum subsp. infantis) with demonstrated health-promoting properties,” they wrote in the Journal of Agricultural and Food Chemistry .
The study builds on earlier work from the same group , published in the same journal in 2011. The wild blueberries were provided by the Wild Blueberry Association of North America and the wild blueberry powder was processed by FutureCeuticals (Monmence, IL).
The beneficial effects of the blueberries are thought to be linked to their flavonoid content - in particular anthocyanins and flavanols.
Consumer interest in blueberries and the compounds they contain has increased in recent years, following results from studies reporting a wide range of health benefits, most notably for brain health and reducing the risk of Alzheimer’s.
“Compelling” data published recently in the American Journal of Clinical Nutrition indicated that blueberry flavonoids could boost endothelial function and enhance heart health.
The new study indicates that the benefits of the berries may also extend to gut health. The researchers recruited 20 healthy men with an average age of 46 and an average BMI of 25 kg/m2, and randomly assigned them to one of two groups. One group consumed a daily 250 ml drink of juice containing 25 grams of wild blueberry powder, while the second group consumed a placebo drink daily.
After six weeks, both groups underwent another six of ‘washout’ before being crossed over to the other group.
Results showed that there was a high variability between all of the participants, but a significant increase in cell numbers of B. longum subsp. infantis was observed in the feces after the wild blueberry drink intervention.
“Specifically, B. longum subsp. infantis changed in the feces of volunteers from 5.9 to 6.3 log(10) cells/g after the WB drink treatment and from 6.00 to 5.9 log(10) cells/g after the placebo drink treatment,” wrote the researchers.
“It should be also mentioned that about half (i.e., 5 of 11) of the subjects had a high increase (i.e., greater than 0.6 log(10)) of B. longum subsp. infantis following the blueberry drink cunsumption, and this was not dependent on initial concentrations of these bacteria.”
Since this bifidobacterial strain has been reported to modulate the immune system, and beneficial influence some gastrointestinal disorders the researchers said that the increase in numbers of this strain could be “quite univocally considered a potential health benefit”.
Source: Journal of Agricultural and Food Chemistry
Volume 61, Number 34, Pages 8134-8140, doi: 10.1021/jf402495k
“Differential Modulation of Human Intestinal Bifidobacterium Populations after Consumption of a Wild Blueberry (Vaccinium angustifolium) Drink”
Authors: Guglielmetti S, Fracassetti D, Taverniti V, Del Bo' C, Vendrame S, Klimis-Zacas D, Arioli S, Riso P, Porrini M.