Does soda drinking cause kidney stones?

Kidney stone formers often ask us whether their soda drinking caused their kidney stones. Many have already taken the initiative to cut out all their soda, thinking it will help prevent future stones. So, what’s the real deal with soda and kidney stones?

The belief that soda drinking is associated with increased kidney stone formation stems from a study of 1,009 males randomized to either refraining from or continuing soft drinks over three years by Shushter and colleagues. In their study, those who refrained were 6.4% less likely to form another stone than those who continued their soda intake. Additionally, they observed that those who refrained from sodas acidified by phosphoric acid as opposed to sodas acidified with citric acid had a more pronounced 15% lower likelihood of forming another stone (Shuster et al, J Clin Epidemiol, 1992). Phosphoric acid is most commonly used in colas (such as Coca Cola) while citric acid is most commonly used in fruit flavored sodas (such as Sprite). Based on this study, avoidance of cola drinks was recommended by some physicians as a way to avoid stones.

Other research has however questioned these early findings. In a study of 45,289 men, intake of 21 different types of beverages and the development of stones was determined over six years. In contrast to the prior study, the authors found that cola intake did not increase stone risk when all factors were considered. They concluded that if a person’s diet was otherwise kept the same, the addition of cola would not increase the risk of stones (Curhan et al, Am Journal Epid, 1996).

Overall, the risk of forming stones from soda drinking appears to be questionable. If true, this risk applies to only phosphoric acid containing sodas, found mostly in dark colored sodas. Kidney stoners who want to play it safe can elect to avoid colas and choose non-cola sodas or other non-soda beverages instead. Cola-loving kidney stone formers might choose colas that don’t use phosphoric acid. (You can easily check whether this is in your beverage by reading the ingredients list on the side of the bottle or can). Some cola brands we’ve found that don’t use phosphoric acid include Pepsi Natural and Red Bull Cola*.

In the end, we feel that rather than focusing on the type of fluid they drink, most kidney stone formers are best served by focusing on overall volume-it’s not what you drink but rather how much you’re drinking. That said, given the link between soda drinking and obesity, we feel that drinking water is always a better alternative that has no calories and is cheap if you use the filtered or tap variety.

*We do not endorse (or criticize) any specific soda brands and only use brand names in this article as examples.

About Dr. Mike Nguyen

Mike M Nguyen, MD, MPH, is a urologist and an Associate Professor of Clinical Urology at the Keck School of Medicine of USC in Los Angeles, CA. He specializes in the treatment of kidney stones with both surgery and dietary prevention and the in the treatment of kidney and prostate cancer using the latest robotic surgical approaches. He sees patients at clinics located in Los Angeles, Pasadena, and La Canada, CA. He is the founder of the www.KidneyStoners.org website.
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14 Responses to Does soda drinking cause kidney stones?

  1. edgar black says:

    so is caffeine a problem or is it ok to drink like tee’s coffee’s.this is my second time passing kidney stones and ive drank coca cola my 33yr life span.im looking to change my ways so any info would be great.is there any foods or spice’s i should stay away from?

    • Mark says:

      From my experience and research, one should be aware of the oxalate content of whatever food or beverage ingested. One should also drink plenty of water to keep kidneys flushed out and prevent calcium and oxalates from remaining in the kidney for too long as they are prone to causing the formation of stones. Eating foods that contain magnesium balance out calcium and tend to reduce or eliminate kidney stone formation. I have found as well that lemon juice dissolves kidney stones and allows them to pass painlessly from the body. I tend to drink about a quart of lemonade a day and squeeze my own with fresh lemons. Putting a little lemon zest from the peel into the lemonade increases its punch. If I don’t drink the lemon over an extended period, I really pay for it!

  2. Andrew says:

    I usually drink an energy before I work out and have a high protein diet throughout the day. I had two stones (both at the same time) 7 years ago and I am worried that I am going to get another one out of no where. I have cut out the energy drinks, I drink more water than I probably need, but in the back of my mind I am worried one is just lingering and in the works. Since I had one before am I at greater risk? I already know the answer to this, but is there a way to check and see if I have one that is forming?

    Thanks for the help.

  3. Brad says:

    I just had a bout of kidney stones…4 of them…BUT…this was 7 years after my first bout with 3 stones. At that time I did two things…in the 7 years since that first time I RARELY, if ever, drank Coke. (Lost 40 pounds too.) I also put a water filter on our sink tap with our well water that is softened as it comes into our house. So, what happened just before this most recent bout of kidney stones…???…

    Within the last three weeks…I started drinking straight Coke once again. Just a bottle a night…I have no idea why…but I did for roughly three weeks. Also, I used the well water…unfiltered…at the tap for making coffee…and what happens???…kidney stones. Just sayin’ it like it is.

    I’m going back to my filtered water I’ve sworn off Coke once again.

  4. Mark Jensen says:

    I had my first horrible bout of kidney stones 3 weeks ago. First my left kidney went, hurting horribly for 5 hours, or most of a night, then my right one plus the L one in the am. They were coincident with buying 5 cans of sugar free “Rock Star” but I think I was also consuming quite a bit of salt. The energy drink had a form of phosphoric acid. I added a bunch a supplements, but I think magnesium was the significant one, and I have not had any kidney pain since recovering.

  5. Tommy Rogers says:

    Forgot to add that after quitting the soft drink I have been stone free for about 3 years.

  6. Tommy Rogers says:

    For many years I had Uric Acid Stones on a regular basis. I have passed 85 stones that were near BB size or larger, the first one had to be removed by surgery. Have passed numerous small flakes that I did not count. One day at lunch the restaurant didn’t have brewed tea so I drank a certain soda. The next morning when urinating the first time I passed probably as many as 200 small flakes. Took 3 more times for it to clear up, passing lesser amounts each time. I wondered if it was the soft drink so I waited 2 weeks and did the same thing, same results, took 4 times for the flakes to disappear. I am interested with corresponding with anyone that has had several Uric Acid Stones.

    • John says:

      I’m right there with you. . I’ve had a ton of stones. (Going with 100) and uncountable little “flakes”. If I drink a pop, just one, within a day or two I will have a stone. Definately has to do with color of pop too. Dark color is a day or two, clear pop doesn’t seem to do it so I’m not quite sure.

  7. Chad T says:

    I just got out of the hospital 2 weeks ago after being admitted due to a kidney stone. It was the most painful thing I’ve experienced. My kidneys weren’t functioning correctly and I couldn’t pass the stone. My urologist said not to drink any brewed tea or dark cola.

  8. lisa says:

    I drink alot of coca cola and i had kidney stones in 2003, i havent had them since then and i drink about 6 cans of pop a day. I recently had a ct scan and i they have found another kidney stone in my right side, so i would say if it takes ten yrs for one to form and i didnt decrease my pop intake that whether or not you drink pop doesnt matter.

  9. Paul says:

    As a middle aged male who used to get kidney stones – but no longer does – I’d advise ditching pop, period. All flavours. I used to drink 2 liters of ginger ale daily, rarely ever any colas, but had stones fairly frequently. Even cutting back to 1 or 2 cans a day didn’t end the stone problem for me. It was a struggle but once the pop habit was broken my kidney stones stopped. Coffee, tea, water, juices, and wine are all I drink now and my kidneys are doing well.

  10. Jasin says:

    I was recently diagnosed with Kidney stones in the ER. I drank a lot of soda (sierra mist) and high content sugar drinks with very little in the way of water. I certainly hope it was the soda because I don’t have time for any more kidney stones.

  11. S Atwell says:

    So what actually defines the “colas” that are spoken of? Are we talking dark colored carbonated drinks or sodas in general?

    • KidneyStoners.org says:

      Colas refers to phosphoric acid containing sodas, found mostly in dark colored sodas (such as Coca Cola). Fruit flavored sodas (such as Sprite) usually use citric acid instead. Some colas don’t contain phosphoric acid. Check the ingredient list if you are not sure.

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