Drinking cranberry juice has been recommended to decrease the incidence of urinary tract infections, based on observational studies and a few small clinical trials. However, a new study published in the January 1 issue of Clinical Infectious Diseases, and now available online, suggests otherwise.
College-aged women who tested positive for having a urinary tract infection were assigned to drink eight ounces of cranberry juice or a placebo twice a day for either six months or until a recurrence of a urinary tract infection, whichever happened first. Of the participants who suffered a second urinary tract infection, the cranberry juice drinkers had a recurrence rate of almost 20 percent, while those who drank the placebo suffered only a 14 percent recurrence.
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via IDsociety
I suspected they used sweetened cranberry juice, so I looked at the methods section of this study:
... Participants were randomly assigned to drink either 8 oz of 27% low-calorie cranberry juice cocktail twice per day or 8 oz of placebo juice twice per day for the test period of 6 months. Study juices were packaged and distributed by Fisher BioServices. Cranberry juice was provided by Ocean Spray Cranberries and was formulated under contract with NCCAM to fulfill research requirements of RFA.AT-03-004 grantees. A Drug Master File for this research grade—low-calorie juice cocktail (LCJC)—is on file with the United States Food and Drug Administration. Research juice was formulated to be similar to the commercially available Ocean Spray LCJC and was sweetened with Splenda (sucralose), exactly as is the retail juice. Commercially grown cranberries from Vaccinum macrocarpon Aiton were used for the juice production. Batches of LCJC were standardized for proanthocyanidin content. Proanthocyanidin is the cranberry juice component that is thought to produce the antiadhering activity against E. coli [20]. Each dose consisted of one 8-oz bottle (240 mL) containing a mean proanthocyanidin concentration of 112 mg per dose (range, 83–136 mg; standard deviation, ±14.1 mg), as measured by Fisher Bioservices by the DMAC(N,N-dimethyacetamicle) method. The placebo juice was formulated by Ocean Spray to imitate the flavor (sugar and acidity) and color of the cranberry beverage, without any cranberry content. In addition to other food and pharmaceutical-grade substances, both juices contained ascorbic acid in their formulations. Fisher Bioservices used identical bottles for the cranberry juice and the placebo beverage. All study juice (cranberry and placebo) was stored under refrigerated conditions (2–8oC) until delivery to study participants.
Patients were instructed to refrain from cranberry- or blueberry-containing foods during the study period. Study juice was delivered to participant's home every 1–2 weeks starting on the day of enrollment in order to promote compliance. ...
via Cranberry Juice Fails to Prevent Recurrent Urinary Tract Infection: Results From a Randomized Placebo-Controlled Trial — Clin Infect Dis.
According to foodInsight, sucralose appears in over 4,000 products and bacteria can't eat it, so it doesn't produce tooth decay. However, another site says bacteria can feed on sucralose:
Splenda, aka sucralose, is a sucrose-like molecule. Basically, they have added Chlorine atoms to sucrose to make it indigestible by humans. However, since it is not digestible by us, it does not get absorbed and passes down the GI tract. It is digestible by bacteria. So in essence, if you consume sucralose, you are sending down an energy source to the bacteria you are trying to starve. So sucralose is not allowed.
That, if true, would by itself make this study inconclusive. But there's another negative to consider. Splenda is the trade name for sucralose, a synthetic compound, sugar modified by adding chlorine atoms, discovered in the 1970s by researchers looking to create a new pesticide. It concentrates in the gastrointestinal tract.
... The human body is very good at detoxifying itself of certain substances, but this is not the case with organochlorine compounds, which are organic compounds that have been chlorinated. Dioxin, one organochlorine compound that is a by-product of the paper bleaching process, is 300,000 times more carcinogenic than DDT, an insecticide that was banned because of its toxicity. These compounds have been linked to birth defects, cancer, and immune dysfunction. These chemicals stay in the body and accumulate over time. According to the Sucralose Toxicity Information Center, the absorbed sucralose and its metabolites (chemically altered substances) concentrate in the liver, kidney, and gastrointestinal tract. Splenda manufacturers claim there is minimal absorption of Splenda and its metabolites. The FDA says there is only 11 percent to 27 percent absorption, but the Japanese Food Sanitation Council says as much as 40 percent is absorbed by the body.
According to claims by the manufacturer, the chlorine part of the sucralose molecule is similar to the chorine part of common table salt (NaCl – Sodium Chloride). However, some would caution that using sucralose may be more like ingesting small amounts of chlorinated pesticides like DDT. ... Research in animals has shown:
- Up to 40 percent shrinkage of the thymus gland. (Critical for the response to disease – the ‘heart’ of our immune system)
- Enlarged liver and kidneys
- Atrophy of lymph follicles
- Reduced growth rate
- via DownToEarth
In my view this study is not examining the action of cranberry juice on UTI, it is examining OceanSpray's formula including Splenda. The researchers don't take into account the possible damaging effects of Splenda on the immune system. Repeat this study with unsweetened organic cranberry juice, and they might find what other placebo controlled studies have.
(1.) Jepson RG, Mihaljevic L, Craig J. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev 2001: CD001321.
Seven trials met the inclusion criteria (four cross-over, three parallel group). The effectiveness of cranberry juice (or cranberry-lingonberry juice) versus placebo juice or water was evaluated in six trials, and the effectiveness of cranberries tablets versus placebo was evaluated in two trials (one study evaluated both juice and tablets). In two good quality RCTs, cranberry products significantly reduced the incidence of UTIs at twelve months (RR 0.61 95% CI:0.40 to 0.91) compared with placebo/control in women. One trial gave 7.5 g cranberry concentrate daily (in 50 ml), the other gave 1:30 concentrate given either in 250 ml juice or in tablet form. There was no significant difference in the incidence of UTIs between cranberry juice versus cranberry capsules (RR 1.11 95% CI:0.49 to 2.50). Five trials were not included in the meta-analyses due to methodological flaws or lack of available data. However, only one reported a significant result for the outcome of symptomatic UTIs. Side effects were common in all trials, and dropouts/withdrawals in several of the trials were high.
via NIH
4 comments:
Nice work, Xeno. It does seem kind of silly to use commercially mfg. Ocean Spray in a study. It would be nice to write up a small critique of the study and send it as a "letter to the editor" to the journal that published it. One might ask why was such a ludicrous study done in the first place, although the authors claim no conflicts of interest. I wonder, who funded the study. A quick glance didn't reveal a source.
This latest study is just one trial and the results need to be put into perspective and weighed against the other positive clinical trials in which cranberry was effective. There are always going to be a few negative studies that come out, especially when looking at the effects of food products or supplements on health due to formulation differences, etc. These are not single compound drugs, so we should expect some variation in the study results.
The most confounding issue in this study is that the predicted recurrence rate for UTI in the placebo group was 30%; however, it turned out to be only about 15% - much lower than expected. Interestingly, those people in the cranberry group also had a similarly low UTI recurrence rate, which, in most studies would indicate that the juice worked well. So a possible explanation for this, given by the study authors, is that the placebo might have contained something that had some activity in prevention of UTI, as well. Interestingly, there were twice as many gastrointestinal issues reported with those participants that were on the placebo.
The other issue I see is that there was not a fool-proof way to measure compliance (or making sure that the participants actually consumed the products). Compliance was based on participants self-reporting that they drank the products. I think busy college-age students can be a tough demographic to test in clinical trials, especially when they are asked to drink something twice a day. A more fool-proof approach to measuring compliance would be to monitor the production of a cranberry metabolite in the urine.
The bottom line is that there are a number of positive studies on cranberry and if women are currently consuming cranberry products for maintenance of urinary tract health, the results of this one study shouldn’t be a reason for them to change their current management practices.
I agree with you this is just one study and we must weigh all the evidence from various studies to make any sort of conclusion. And, yes, it's interesting there was a low UTI in both test and control groups. Perhaps indicating the context in which both groups may have been found during the study? But, the issue about compliance works into all such similar studies, a weakness of the paradigm, not the study itself. It seems.
And, yes, there are a number of positive of studies concerning cranberries. But, what about the issue, which Xeno raised, concerning specific ingredients in "Ocean Spray" the substance used in this study?
Actually, the "Light" Ocean Spray Cranberry Juice Cocktail product with 27% cranberry has been used successfully in previous studies – a major clinical trial was published in Journal of American Medical Association (Avorn, J.; Monane, M.; Gurwitz, J.; Glynn, R.; Choodnoakiy, I.; Lipsitz, L.A. Reduction of bacteriuria and pyuria after ingestion of cranberry juice. JAMA 1994, 271, 751-754).
The product used in the current study was not an “off the shelf” Ocean Spray product, but was specially formulated by a contracting agency and did not have exactly the same ingredients as the commercial product.
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