Cranberries and Bladder Infections

The following is some information on Cranberries and their chemical makeup and usefulness. I thought it might be interesting info for sometime in the future. It is interesting and helpful to those that suffer from chronic bladder infections. Here is some info with references that I hope will help.

"The action of cranberry juice is due to acidifying the urine and the  antibacterial  effects of a cranberry component, hippuric acid. In addition, recent studies  have shown components in cranberry juice to reduce the ability of bacteria to adhere to the lining of the bladder and urethra." ----American Council on  Collaborative Medicine  "The earliest investigations into the mode of action of cranberry juice focused on the effects on the acidity of the urine, and increased concentration of hippuric  acid in the urine. However, it was found that the increase in acidity was small and transient and so would not impact upon the activity of the  uropathogens.

In addition, although  Hippuric acid is known to possess bacteriostatic properties, the levels  detected in the urine were insufficient to achieve such bacteriostasis. More  recent studies have shown that cranberry juice and cranberry juice enriched  with fructose can inhibit the adherence of urinary tract isolates of E.coli to human uroepithilial cells.

The next step has been to try to identify the  constituents of cranberry juice which contribute to the anti adherence  activity. It has been found that the juice contains at least two adherence  inhibitors: one low molecular weight. The low MW compound specifically  inhibited the activity of the type 1 fimbriae. The low MW compound has been  identified and constitutes the fructose component of the juice where it is  believed to interfere with the mannose specific lectin on the E.coli wall  binding to the reception site on the epithelial cell surface. Fructose had  no inhibitory action on E.coli which had Type P fimbrial. However, the high  MW compound found in cranberry juice was found to profoundly inhibit Type P  fimbriae Fructose enriched cranberry juice therefore has the potential to inhibit the attachment of both types of E.coli fimbriae which are most  commonly associated with UTI." 
---BioMed Newsletter 1991, Vol 2, Issue 6 

"A germ called E. Coli is a normal inhabitant of the colon. In some people,  it can climb from the surrounding skin up into the bladder by sticking to the  cells that line the urinary tract. Cranberry and blueberry juices contain a  chemical that prevents E. Coli from sticking to urinary tract cells so they can't climb up into the bladder." 
---JAMA (Report #6149 3/15/94)

"The study shows cranberry juice reduces pre-existing bacteria and the  occurrence of new bacteria in the urinary tract. It didn't test whether  drinking cranberry juice prevents infections. Contrary to a popular belief,  cranberry juice doesn't reduce bacteria by making urine more acidic.  Researchers believe cranberry juice inhibits bacteria from "sticking" to the  bladder wall where they can multiply and cause infection."
---Mayo Clinic Health Letter, June 1994 

"For years, doctors have routinely advised patients to drink cranberry juice  to prevent  urinary infections. In fact, it is cited as an effective remedy for this  problem in the U.S. Pharmacopeia, the official listing of drugs in the United  States. At one time, scientists believed that cranberry acidified the urine,  and in the process, killed invading bacteria that could cause infection.  Recently, however, Dr. Anthony Sabota, a scientist at Youngstown State  University in Ohio, offered another possible explanation. His studies  suggest that cranberry prevents bacteria from sticking to the wall of the  bladder, thus flushing the potential troublemakers out of the body before  they can do their damage."
--- Earl Mindell, "Herb Bible"

The information I've seen indicate that cranberries contain a yet-unknown factor that prevents bacterial adhesion to urinary tract walls. No toxins that I know of.  I believe cranberries contain benzoic acid. I have trouble with  the probably synthetic benzoic acid used as a preservative (probably created by mold fermentation), I have no such problem with cranberries.