Compositions and methods for supporting health, especially renal health, comprising ketonic agents that recapitulate beneficial effects of ketosis by exogenously administered agents. The agents include BHB, analogs thereof, and GPR109A agonists. The agents may further include crystal precipitation inhibitors which synergistically improve treatment of certain renal conditions. The agents may be used in dietary supplements and therapeutic compositions for the treatment of cystic kidney diseases such as polycystic kidney disease, ciliopathies, and other conditions.