I've been reading more about Vitamin D3 and apparently it is nourishing to the whole urinary system (including other benefits). Someone mentioned it is fat-soluble, which is true, so you can also end up with side effects if you have too much.
Speaking of UTIs, several articles indicate a link between Vitamin D deficiency and UTIs.
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Vitamin D supplementation may prevent urinary tract infectionsA five year-long randomized controlled trial (RCT) discovered that vitamin D supplements helped prevent UTIs. Research has shown that vitamin D helps fight infection by increasing the production of antimicrobial peptides. These peptides assist the body in destroying the cell walls of viruses and bacteria."
https://www.vitamindcouncil.org/vitamin ... AsQ3uJOnIUhttps://www.ncbi.nlm.nih.gov/pubmed/27357103Also,
Vitamin D deficiency may increase bladder cancer risk."Five out of the seven studies found that the risk of bladder cancer goes up when vitamin D levels are low. Higher vitamin D levels also correlated with better survival and outcomes in people with bladder cancer."
https://www.medicalnewstoday.com/articles/313933.php