Infections of the urinary tract are a significant cause of patient visits to health care providers. In the United States, at least 8 million visits, and $2 billion in costs, are attributed to treatment of uncomplicated urinary tract infections (UTIs).
Anatomy of the Urinary Tract
The urinary tract is the system by which the body regulates its water level, manages blood pressure, and eliminates wastes. It is composed of the kidneys, ureters, urinary bladder, and urethra. In a complicated process, blood is filtered as it passes through the kidneys. The resulting wastes and some water pass from the kidneys to the bladder by way of connecting tubes (ureters). In the urinary bladder, urine collects until its quantity stretches the bladder and causes discomfort. From the bladder, another tube called the urethra allows urine to be consciously passed through a muscular sphincter and out of the body.
Signs and Symptoms of Uncomplicated UTIs
- · Difficult or painful urination
- · Frequent urination or feelings of urgency
- · Pressure above pubic bone
- · Pink-tinged urine
Uncomplicated UTIs involve the urethra and sometimes the bladder. They are more common in women, and frequently become reoccurring conditions. They are usually caused by opportunistic bacteria like Escherichia coli (E. coli) that exist on humans as normal flora, and are unrelated to pathogens implicated in sexually transmitted diseases (STDs). Controversy abounds as to the reasons why humans get UTIs but they have been associated with hygiene, irritation, sexual practices, urinary catheters, disease conditions, and anatomical irregularities. Contaminated foods have also been implicated as possible causes.
Treating Uncomplicated Urinary Tract Infections
Though a course of antibiotics is still the primary treatment for UTIs, concerns regarding the evolving resistance of bacteria are driving exploration of new, novel therapies. Many of which involve substances that affect the ability of these pathogens to attach to surfaces of the urethra and bladder. One such material is D-mannose.
The Mechanism for D-Mannose in the Treatment of Urinary Tract Infections
D-Mannose is a simple 6-carbon monosaccharide isomer of glucose found in fruit, sweet potatoes, and corn. This substance is easily absorbed and unlike other sugars, is not metabolized into fat or glucose by the liver. Instead, it remains intact and is transported to cells by the blood, where it is utilized as a part of their surface receptors. Excess D-mannose is quickly eliminated by the kidneys and becomes a part of urine which is flushed out.
Many variants of E. coli have appendages that attach to the D-mannose components of cell receptors, allowing them to adhere to the lining of the urethra and bladder. This adherence is crucial for them to grow and cause disease. When a large amount of D-mannose is ingested, it passes to the urine and coats bacteria, inhibiting their ability to attach and cause disease. They are then easily voided out in the urine.
Dosage and Adverse Effects
Research on dosage is ongoing but the anecdotal adult standard appears to be three (3) grams per day in divided, one (1) gram doses, for a duration of 3-5 days. Adverse effects appear to be mild with the most common being nausea.
Additional Resources
Foxman, “Epidemiology of urinary tract infections: incidence, morbidity, and economic costs.,” Disease-a-month 49, no. 2 (2003): 53–70.
Miller and Angela W. Tang, “Treatment of Uncomplicated Urinary Tract Infections in an Era of Increasing Antimicrobial Resistance,” Mayo Clinic Proceedings 79, no. 8 (2004): 1048 -1054.
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