Role of calcium supplements in the pathogenesis of urinary tract infections

Abstract

It has been previously shown that calcium ions are able to reduce the anti-adherence activity of Tamm-Hosefall glycoprotein (THP). Upon duplication of this effect of calcium ions on THP, it was observed that calcium ions alone had a similar effect on the adherence of bacteria to exfoliated epithelial cells in humans. This study focuses on the role of excess calcium in relation to urinary tract infections. Also, the effect of calcium supplements on urinary excretion of calcium was investigated. A constant increase in bacterial adherence was observed as the concentration of calcium was increased whether the preincubation or incubation medium was phosphate buffered saline (PBS), sterile urine or a combination of both. An increase in the concentration of calcium to 10 mM or 20mM more than doubled the number of bacteria adhering to exfoliated epithelial cells in vitro. Other monovalent and divalent ions that are abundant in urine were tested to see whether they affected bacterial adherence in the same manner as the calcium ions. Sodium and potassium ions did not promote bacterial attachment while magnesium ions decreased the adherence of bacteria to exfoliated epithelial cells. The amount of calcium excreted in the urine after the ingestion of TUMS, an oral calcium supplement, is approximately equal to the concentration of 10 mM calcium that was previously shown to increase bacterial adherence in vitro. These results suggest that calcium supplements may increase the potential for urinary track infections, particularly among postmenopausal women taking calcium supplements as prophylaxis against osteoporosis.