Dehydration and UTI
Dehydration and UTI: Can Dehydration Cause UTI?
Urinary Tract Infections (UTIs) are caused when harmful bacteria grow in your urinary system, in your kidneys, ureters, bladder, or urethra—anywhere urine passes through. These infections can cause a number of unpleasant symptoms. Commonly, UTIs are experienced as strong and persistent urges to urinate, burning sensation while peeing, and pelvic pain .
UTIs are a surprisingly common condition despite the potentially embarrassing symptoms (patients may experience very sudden urges to pee, and if that comes on at the wrong time then a spare pair of trousers may be required…). It has been estimated 20% of women will have at least one UTI during their lifetime .
But what do UTIs have to do with dehydration?
Can dehydration cause UTI? Bacterial growth in your urinary tract is usually controlled with a combination of urinary and mucus flow and a release of chemicals targeted at bacterial growth interference . It seems logical to suggest that since fluid intake increases the urine volume and frequency of peeing, hydration may help flush out any unfriendly bacteria. Forcing the passing of fluids has long been advocated in the therapy of urinary tract infections . NHS Scotland also recommends staying well hydrated as a means of preventing UTIs .
But what’s the evidence?
Urine can fight bacteria, that much is known. Studies have shown that pee with a high urea concentration can have an inhibitory effect on the growth of some disease-causing bacteria. The more concentrated the urine, the better it is at fighting off bacteria in your urinary system.
In one study, rats given little water (those with more concentrated urine) had lower bacteria count in their pee than rats given plenty of water. The rats that received less water also showed a lower degree of renal infection. The problem with this, however—and animal studies in general—is that rats aren’t people, and that rodents generally have much more concentrated urine than humans.
When a similar study was done in humans, bacteria in more concentrated urine samples had a lower survival rate indicating that concentrated pee is better at preventing bacterial growth . Additionally, in a small study investigating possible risk factors for UTIs, when women with UTIs were compared to women with other unrelated infections, no association was found between susceptibility to UTIs and the volume of fluids consumed .
This doesn’t look good for the power of hydration in preventing UTIs. However, the evidence is actually conflicting and complex, as it often the case in science.
One study in which 141 girls were evaluated between 1996-1999 found that most girls experiencing three or more urinary tract infections had common behaviors, namely infrequent voiding (not peeing much), poor fluid intake, and void retention (holding in pee) .
Another example of a positive association between hydration and UTI prevention was described by the National Institute for Health and Care Excellence (NICE). This recent project was able to reduce the incidence of UTIs in local care homes by promoting hydration. Changes made during the project included: staff hydration training, introduction of a ‘7 structured drinks’ round, residents’ hydration training, food and fluids charts. These changes reduced the admissions of patients with UTIs to hospital from care homes from 18 in 2015/2016 to just 4 in 2017/2018. Additionally the incidence of UTIs reduced from an average of one every 13 days to one every 47 days .
Does dehydration effect UTIs?
The evidence around hydration and UTIs is mixed at best. Each of the studies referenced have their own merits and limitations. However, most credible online resources list hydration as a prevention for UTIs or have dehydration as a risk factor for developing a UTI. Since drinking more fluids has numerous benefits, we’re siding with NHS Scotland in recommending proper hydration as an effective way to help ward off UTIs.
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 Mayo Clinic. Urinary Tract Infections. 25 August 2017. An overview of the causes and symptoms of UTIs.
 Nature. Mild dehydration: a risk factor of urinary tract infection? R Beetz. 2003. This research article reviews the evidence available as of 2003 from experimental and clinical studies of the effects of hydration on UTIs.
 NHS inform. Urinary tract infection (UTI). 07 May 2018. This NHS Informs article gives an overview of the symptoms, treatment, causes and prevention of UTIs.
 Europe PMC. Behavioral and functional abnormalities linked with recurrent urinary tract infections in girls. Mazzola et al. 2003. This study sought to identify the behaviors correlated with girls suffering from recurrent urinary tract infections.
 NICE. Reducing incidence of Urinary Tract Infections by promoting hydration in care homes. April 2018. The East Berkshire Clinical Commissioning Group showed that improving hydration in local care homes was able to reduce rates of UTIs amongst residents.
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