The anti-UTI effects of cranberry are well-documented and are reported to due to PACs obstructing the adherence of E. coli to epithelial cells.
There are also reports that commercial probiotic Lactobacillus sp. May have inhibit the growth and displace E. coli, and so the researchers examined if there could be synergistic effects of combining cranberry PACs and select probiotic strains to further block the pathogenic effects of E. coli.
Results published in the Journal of Functional Foods indicated that the presence of probiotics did not inhibit the anti-E. coli invasion activity of the cranberry PACs at concentrations greater than 36 micrograms per mL.
“This observation is primarily attributed to the presence of adhesive organelles on the surface of [E. coli] but not on the surface of L. acidophilus,” wrote researchers from the University of Wisconsin–Madison, Complete Phytochemical Solutions, and UAS Laboratories. The PACs could agglutinate or bind the E. coli because of these adhesion organelles.
In addition, incubating E. coli with a blend of L. acidophilus, L. gasseri, L. plantarum, L. rhamnosus and B. animalis subsp. Lactis in the absence of PACs was found to prevent invasion by E. coli, “indicating that probiotics may contribute to providing an inhospitable environment of ExPEC in the gastrointestinal tract”, they said.
In 2004 France became the first country to approve a health claim for the North American cranberry (Vaccinium macrocarpon) with at least 36mg of proanthocyanidins (PAC) to “help reduce the adhesion of certain E. coli bacteria to the urinary tract walls”, and subsequently fight urinary tract infections (UTIs).
“[T]his pilot study provides insight on the potential mechanistic role of the combination of (a) probiotics selected from common vaginal inhabitants along with (b) c-PAC from high quality cranberry powder, on inhibiting the invasiveness of [E. coli],” wrote the researchers. “The study of these bioactive compound combinations is important to facilitate the development of future functional foods.
“Clearly, further studies are needed to confirm these in vitro findings in an in vivo system, but this study provides evidence that rationale product design by combining synergistic functional food ingredients may have a role in promoting health in targeted applications.”
“Supporting the efficacy of finished product formulas”
Dr Greg Leyer, Chief Scientific Officer, UAS Labs and co-author on the paper, told NutraIngredients-USA: “UAS Labs continues to invest in research to support efficacy of finished product formulas. The intent of the study was to better understand the potential mechanisms of probiotics when combined with specific cranberry bioactive compounds, and we observed interesting synergies.
“We’re pleased to offer our customers worldwide the confidence knowing these products are solidly backed by science.”
Source: Journal of Functional Foods
August 2016, Volume 25, Pages 123–134, doi: 10.1016/j.jff.2016.05.015
“Ability of cranberry proanthocyanidins in combination with a probiotic formulation to inhibit in vitro invasion of gut epithelial cells by extra-intestinal pathogenic E. coli”
Authors: M.A. Polewski, C.G. Krueger, J.D. Reed, G. Leyer