You have probably received a lot of advice about calcium intake from family and close friends ever since you developed kidney stones. In this article, we will inform you about the role of calcium in stone formation and how you should really manage its intake.
Studies on the role of calcium in kidney stone formation (Curhan et al., Meschi et al., etc.) verify that calcium intake reduces the risk of symptomatic kidney stone formation. These results contradict the belief or opinion that the risk of kidney stone formation increases due to calcium intake.
The key question to understand how calcium intake can reduce kidney stone formation is: what is the role of calcium in kidney stone formation? Calcium increases the intestinal absorption of oxalate, a key promoter in the formation process. Therefore, a reduced concentration of calcium leads to an increase in free oxalate, known as hyperoxaluria. In other words, reduced consumption promotes an increase in a significant risk factor for kidney stone formation.
In conclusion, should I restrict my calcium intake? The answer is no. Severe restriction of calcium intake is associated with an increased risk of kidney stone formation, as it leads to an increase in urinary oxalate concentration. Therefore, the recommendation is to maintain a diet with normal calcium intake (approximately 1000 mg daily), although we always recommend confirming with your urologist.
References:
Curhan GC, Willett WC, Rimm EB, Stampfer MJ. A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones. N Engl J Med. 1993 Mar 25;328(12):833-8. doi: 10.1056/NEJM199303253281203. PMID: 8441427.
Prezioso D, Strazzullo P, Lotti T, Bianchi G, Borghi L, Caione P, Carini M, Caudarella R, Ferraro M, Gambaro G, Gelosa M, Guttilla A, Illiano E, Martino M, Meschi T, Messa P, Miano R, Napodano G, Nouvenne A, Rendina D, Rocco F, Rosa M, Sanseverino R, Salerno A, Spatafora S, Tasca A, Ticinesi A, Travaglini F, Trinchieri A, Vespasiani G, Zattoni F; CLU Working Group. Dietary treatment of urinary risk factors for renal stone formation. A review of CLU Working Group. Arch Ital Urol Androl. 2015 Jul 7;87(2):105-20. doi: 10.4081/aiua.2015.2.105. Erratum in: Arch Ital Urol Androl. 2016 Mar;88(1):76. Ferraro, Manuel [added]. PMID: 26150027.
