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Can Alkaline Water Treat Kidney Stones? It’s Unlikely, Say Researchers

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Contrary to what the packaging may allude to, bottled “alkaline” water likely can’t treat recurring kidney stones, according to a new study.

After testing five brands of bottled water, the researchers from the University of California, Irvine, found that none contained significant levels of alkali that could raise urine pH enough to affect the development of kidney stones.

The findings were published in the Journal of Urology.

Message on a bottle

Alkaline water has a higher pH level than tap water. This is achieved by adding nutrients to the water to make it more alkaline. Why do such a thing? Because drinking alkaline water is alleged to help prevent cancers and heart disease. These apparent benefits stem from limited research, however, and researchers have called for more studies to verify the claims.

Now, the research team from the University of California, Irvine, have carried out one such study, and their findings haven’t exactly supported the claims of alkaline water acolytes.

The team investigated whether alkaline water could benefit patients with kidney stones. Given that these patients are often prescribed urinary alkalinization therapy for stone dissolution, the researchers wondered whether alkaline water could serve as a more accessible substitute.

The team put five alkaline water products through anion chromatography and direct chemical measurements to determine their mineral contents. The alkaline content of each bottle of water was then compared to that of potassium citrate (the gold standard for urinary alkalinization) as well as to other beverages and supplements used to augment urinary citrate.

The pH levels of the bottled alkaline water ranged between 9.69 and 10.15. Physiologic alkali content was considered minimal (less than 1 milliequivalents per liter, mEq/L) for all brands when compared to common stone treatment alternatives such as potassium citrate. The waters’ alkali contents even paled in comparison to the several synthetic beverages and other supplements. Orange juice, for instance, has a typical alkali content of up to 15 mEq/L. The researchers say the fruit juice had the lowest estimated cost to achieve the target alkali concentration of 30-60 mEq/L per day. 

“While alkaline water products have a higher pH than regular water, they have a negligible alkali content – which suggests that they can't raise urine pH enough to affect the development of kidney and other urinary stones,” said Roshan M. Patel, an assistant clinical professor of urology at the University of California, Irvine.

“Our findings may help to guide the selection of other treatments, including beverages and over-the-counter products, for preventing recurrent urinary stones,” Patel added.

Piedras P, Cumpanas AD, McCormac A, Lavasani SAM, Gorgen ARH, Rojhani A, Vu MC, Bhatt R, Asplin J, Tano ZE, Landman J, Clayman RV, Patel RM. Alkaline water: help or hype for uric acid and cystine urolithiasis? J Urol. 2024. doi: 10.1097/JU.0000000000003767