Study supports cranberry dose levels for urinary health
1. Study supports cranberry dose levels for urinary
health
By Stephen Daniells, 01-Jun-2010
Related topics: Antioxidants/carotenoids, Polyphenols, Women's health, Suppliers, Research
The abilityof cranberryproanthocyanidins (PACs)isdependentonthe dose,withhigherdoses
significantlymore effective atmaintainingurinaryhealth,saysanew study.
The study supports levels outlined bya French health claim,issued in 2004,for the North American cranberry
(Vaccinium macrocarpon) with atleast36 milligrams ofproanthocyanidins (PAC) to “help reduce the adhesion of
certain E. coli bacteria to the urinary tract walls”, and subsequentlyfighturinary tract infections (UTIs).
Indeed, a lower dose of 18 mg of cranberry PACs was less effective, according to the results of a
randomized, double-blind versus placebo study based in Japan, Hungary, Spain and France.
On the other hand,a higher dose of 72 mg was even more efficientat protecting againstbacterial adhesion in the
urinary tract, according to findings published in the open-access journal BMC Infectious Diseases.
PACs are also notexclusive to cranberries,butcan be found in a range of foods,including green tea,grapes,apples,
and chocolate.However, the main type of PACs in cranberry – called A-type PACs - are differentfrom those in these
other source – called B-type PACs. Only cranberry PACs may prevent bacterial adhesion.
Led by Amy Howell from the Marucci Center for Blueberry and Cranberry Research and Extension at
Rutgers University, the researchers note that, while the urinary tract benefits of cranberry are well
documented, it was not known how cranberry PACs may affect the persistence in urine samples over a
longer time period. They also sought to determine the "most effective dose per day and to determine if the
urinary anti-adhesion effect following cranberry is detected within volunteers of different origins".
Howell and her co-workers recruited 32 volunteers from the four countries and randomlyassigned them to receive 0,
36 or 72 milligrams ofPACs per day in Japan and Hungary, and 0, 18 and 36 milligrams per day in France and
Spain.Participants crossed over to all of the interventions with one week washoutbetween stages.
The researchers used the commercially available Urell product supplied by France’s Pharmatoka, and the
PACs content was determined using the new DMAC method, state the researchers.
Results showed that a dose-dependent effect. After six hours the 18 mg dose displayed an anti-adhesion
activity of 50 per cent, compared with an average of 90 per cent for the 36 mg dose and 100 per cent for
the 72 mg dose, said the researchers.
After 24 hours, no anti-adhesion activity was displayed for the lower dose, while the 36 and 72 mg doses
had anti-adhesion activities of 12.5 and 50 per cent, respectively.
“These results highlighted for the first time that to achieve a bacterial anti-adhesion effect in
urine, 36 mg of cranberry PAC equivalents per day is effective, but 72 mg may offer a [day and
night] protection,” wrote Howell and her co-workers.