Chronic low fluid intake has a role in the development of urinary system diseases such as urolithiasis, urinary tract infection, chronic kidney disease and bladder cancer.
This post is restricted to the impact of fluid intake in the prevention of urinary tract infection

First of all, lets talk about urinary tract infections. Its causes, prevalence e.t.c

1. Urinary tract infection results from a bacterial contamination of the genitourinary tract1.

2. It is prevalent in both men and women of all age groups.

3. Its frequency is about 50 times higher in adult women..More than half of them present with at least one UTI at some stage during their lives2

4. Its common symptoms include difficult, painful and frequent urination, haematuria, supra-pubic pressure.

5.Community acquired UTIs is complicated by the fact that Uti is not a single clinical entity3.

6. The presence of asymptomatic bacteriuria has been established as a reliable predictor for the development of symptomatic UTIs4.

7. In the US, the prevalence of symptomatic bacteriuria ranges from 5 to 6% in women aged 18- 40 years up to 20% in older, ambulatory adults.

8. Common pathogens implicated in UTIs come from the enteric flora and involve mostly Escherichia coli (>70-95%) and Staphylococcus saprophyticus (<10%).

9. Patients with diabetes, multiple sclerosis or HIV/AIDS, and those with underlying urological abnormalities , are more susceptible to UTIs than the general population.

10. Higher prevalence of asymptomatic bacteriuria and UTIs has been reported in lower income countries5.


Mechanism by which micro organisms attack the urinary tract.

As the bacteria increases in number in the urinary tract, they start to destroy the antimicrobial peptides lining its epithelium, disrupting its integrity1.
This coupled with other factors, favours bacterial adherence to the epithelium, where once anchored, the pathogens are phagocyted into the cytoplasm of epithelial cells1. Infection occurs when a critical mass is reached, eventually resulting in cell exfoliation.
Bacterial adherence is therefore an important risk factor for UTIs.

Fluid intake and urinary tract infection risk

The potential role of fluid intake in the prevention of UTIs can be explained by the following factors:

1. Increasing diuresis (urination) has a diluting effect on contaminating bacteria and virulence factors 6.

2. The flushing effect that occurs with each void, washes out contaminants and cleans the epithelia.

3. Increasing the frequency of voiding has a shrinking effect on the bladder, effectively reducing the available surface area on which bacteria can thrive.

4. Fluid intake helps to maintain optimal urine pH. Low fluid intake is associated with an increase in urine osmolality and acidity. As a consequence, the epithelium is indirectly predisposed to bacterial adhesion, and therefore to an increased risk of UTI.

Self monitoring of urine osmolality, using either a probe or a urine colour chart, can alert people with recurrent UTIs when they are not drinking enough water. This has been associated with a significant reduction in incidence of UTIs compared with the period in which the probe was not used.

However, given the scarcity and inconsistency of the available experimental and clinical data, it is not possible to draw any firm conclusions on the utility of UTI prevention (primary or secondary) as a basis on which to make recommendations about daily fluid intake.

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