Researchers tested five brands of trendy "alkaline water" and found no evidence to support claims they help prevent kidney stones.
Marketing campaigns have suggested that alkaline water, with its typical pH between eight and 10, offers many health benefits. For example, proponents of alkaline water say it may help raise urinary pH, improve bone health, and boost post-exercise hydration.
However, due to the lack of scientific evidence supporting the benefits of these trendy water products, it needs to be clarified whether they live up to the hype.
Can alkaline water impact kidney health?
Raising urinary pH can be helpful for people with kidney stones. Doctors often prescribe individuals with certain types of kidney stones a compound called potassium citrate to raise urinary pH. The problem is that potassium citrate comes in a large tablet that must be taken several times a day, which makes adhering to this treatment challenging for some people.
So, if alkaline water could raise pH levels in urine, it might be a more feasible option for kidney stone prevention.
To examine whether alkaline water products can prevent kidney stones, researchers from the University of California, Irvine, California, analyzed five alkaline water brands — Essentia, Smart Water Alkaline, Great Value Hydrate Alkaline Water, Body Armor SportWater, and Perfect Hydration — to determine mineral and alkaline content.
Then, the team compared the alkaline levels in these bottled products to levels found in potassium citrate, baking soda, and beverages such as coconut water and orange juice.
The study, published in the February issue of The Journal of Urology, found that Body Armor SportWater had the highest pH at 10.15 and Smart Water Alkaline had the lowest pH at 9.69. Essentia, Great Value, and Perfect Hydration hovered around 9.9.
However, the study's authors say that in addition to a high pH, a beverage or food must also contain organic anions that create alkali when metabolized to provide a clinically significant alkali load. The alkaline water products tested only had trace amounts of minerals and organic anions, which is not enough to help prevent kidney stones.
"Commercially available alkaline water has negligible alkali content and thus provides no added benefit over tap water for patients with uric acid and cystine urolithiasis," the study's authors wrote.
However, the team suggests that aside from standard treatment with potassium citrate, which provides organic ions, drinking orange juice may also lead to significant increases in urine citrate and pH. Baking soda, which has a high alkali load, can also potentially increase urine pH, but its sodium content is concerning.
Because this was a laboratory study, the scientists say clinical trials are needed to test these and other high-alkaline foods and beverages to determine if they can raise urinary pH in people with uric acid or cystine stone-forming health conditions.
Until scientists know more, people with these kidney conditions should discuss any potential treatment options with their healthcare provider to ensure the effective prevention of kidney stones.
- The Journal of Urology. Alkaline Water: Help or Hype for Uric Acid and Cystine Urolithiasis?