Calcium phosphate kidney stones
Nephrolithiasis consists of the formation of kidney stones, which are deposits of minerals and salts that form inside the kidneys. Kidney stones can be made up of up to 6 different types of components, although calcium phosphate stones occur in 20% of cases1.
What are they?
Calcium phosphate kidney stones form when urine becomes supersaturated with calcium phosphate. This supersaturation leads to the formation of crystals that eventually form calcium phosphate stones. It should be noted that this type of kidney stone is strongly associated with conditions such as hyperparathyroidism and renal tubular acidosis. In addition, it is highly correlated with a high urinary pH (above 6.2). For this reason, patients with this type of kidney stone should focus on reducing urinary pH (below 6.2), increasing water intake, and diet1,2.
How to avoid or prevent them? 1-3
1. Change your diet
As we have mentioned on other occasions (uric acid kidney stones , calcium oxalate kidney stones), this type of kidney stone is strongly related to your diet. To prevent their formation, you should:
- Limit sodium intake
- Increase consumption of dietary supplements with specific inhibitors for calcium oxalate stones that promote acidification of urinary pH.
2. Drink enough fluids
As we have mentioned on other occasions (uric acid kidney stones, calcium oxalate kidney stones), don't forget that the most important thing to prevent stones is to drink 2 to 3 liters of liquid daily (preferably water). We will know it is enough when the color of our urine is almost clear.
3. Increase your physical activity
As we have mentioned on other occasions, an increase in physical activity has been shown to be associated with a decrease in the risk of stone formation4.
4. Control your urinary pH and use aids to inhibit crystallization
The process of calcium phosphate kidney stone formation is strongly associated with a specific urinary pH range (above 6.2). For this reason, the recommendation is to maintain a preventive range below 6.22.
Remember to use dietary supplements to lower your urinary pH and obtain inhibitors of kidney stone crystallization. In other words, prevent the appearance of new kidney stones.
References:
[1] S. Tekgül et al., “EAU Guidelines on Urolithiasis,” Eur. Assoc. Urol., vol. 69, no. 3, pp. 475–482, 2016.
[2] F. Grases, A. Costa-Bauzá, I. Gomila, M. Ramis, A. García-Raja, and R. M. Prieto, “Urinary pH and renal lithiasis,” Urol. Res., vol. 40, no. 1, pp. 41–46, 2012.
[3] P. M. Ferraro and M. Bargagli, “Dietetic and lifestyle recommendations for stone formers.,” Arch. Esp. Urol., vol. 74, no. 1, pp. 112–122, Jan. 2021.
[4] P. M. Ferraro, G. C. Curhan, M. D. Sorensen, G. Gambaro, and E. N. Taylor, “Physical Activity, Energy Intake and the Risk of Incident Kidney Stones,” J. Urol., vol. 193, no. 3, pp. 864–868, 2015.
