A study by Swedish researchers has found that boosting vitamin D levels in postmenopausal women to proper levels provides potent protection against urinary tract infections (UTIs). The researchers noted that vitamin D induces the production of cathelicidin, a human antimicrobial peptide secreted by bladder epithelial cells. Cathelicidin protects the urinary tract from threatening infections. The researchers examined biopsied bladder tissue from healthy postmenopausal women before and after intake of vitamin D over three months. Bladder cells infected with the bacterium E. coli, which causes UTI, showed a significant increase in cathelicidin expression after vitamin D supplementation. Taking a supplement to restore appropriate vitamin D levels “may therefore help prepare the bladder epithelium to mount a stronger and faster immune response once bacteria enter the bladder,” researchers concluded.