- Cranberry juice was noted to be more effective than cranberry capsules or tablets in subgroup analysis. However they concluded that hydration when managing a UTI may have resulted in a more successful UTI resolution outcome which may negate the effect of the cranberry juice itself.
- The mechanism behind the protective effect of cranberries against UTIs has not yet been fully determined, thus the benefits of cranberry may result from other unknown substances in the juice, which are not available in cranberry capsules and tablets.
- Drinking a large amount of cranberry juice with high sugar content might raise concerns about sugar control in diabetic patients, and it may cause severe gastrointestinal upset or other adverse effects. Is it realistic to expect UTI sufferers to consume high quantities of Cranberry juice daily?
- Most of the trials did not report their trial processes adequately and suffered from a high proportion of subjects lost to follow-up. This negates any potential initial benefit of using a cranberry product.
- The administration of cranberry-containing products differed significantly in form, daily dosage and dosing frequency in each of the studies. Three trials did not specify the actual cranberry amount used daily.
- Nine of the trials used cranberry juice, and four used cranberry capsules or tablets. Six trials used cranberry-containing products provided by the same cranberry manufacturer and several studies were sponsored by manufacturers, clear bias at work.
- Cranberry-containing products were administered for no longer than six months in most trials.
