Does drinking a lot of soda cause kidney damage?

This really smells like an urban legend to me, but on another message board I frequent, somebody claims that a cousin of hers was diagnosed with severe kidney damage, and his urologist apparently told him that years of excessive diet soda consumption contributed to the problem.

Is there any truth to this? I drink quite a bit of diet soda myself. I did a quick Google search, but didn’t turn anything fruitful up, at least not at first glance.

There are certainly people who claim that it does, although none of them were able to [thread=155920]convince me[/thread]. A lot of the arguments seem to be of the “It’s soda it must be bad” type rather than the “Here’s a study which shows it” type.

Most of the cites I believe seem to say that the water in diet soda does more good than the caffeine/whatever else does harm, so that people who drink a lot of diet soda have a lower risk of kidney stones than average. However, there are a lot of conflicting cites out there, and I’m not qualified to judge which is more reliable.

Too much sugar intake from any source can cause diabetes which is pancreatic damage. Maybe your source got confused between the kidney and the pancreas?

Y’know, I’m just not sure who to believe any more. My urologist told me, about a year and a half ago, that drinking soda (diet or not) makes the urine more alkaline, leading to increased development of kidney stones (for some reason, I grow 'em like crazy!). So, for a year, I gave up sodas entirely. Stuck to unsweetened tea, coffee, and water, with the occasional beer or glass of cranberry juice thrown in for good measure. Well, about a year later, I had to have surgery on my right kidney to remove 4 stones, and after the surgery my doctor told me that the inside of my right kidney looks like a “cobblestone street” (his exact words) with all the new stones that are growing in there! So, if, presumably, many of those stones had started growing in the prior 12 months, then giving up soda didn’t seem to do me much good! Now, I’m back to drinking a diet soda with my dinner.

I have just one issue with that, although you’re right about the sugar intake thing.

The question is about diet sodas, which contain no sugar.

This is not true.

The American Diabetes Association

Diabetes can cause kidney damage.

Yes, uncontrolled diabetes can cause kidney damage, and no, diabetes is not caused by eating too much sugar. But the guy in the anecdote was drinking diet sodas, anyway, so the question is whether there’s something about sodas, apart from the sugar content, that would cause the problem. Carbonation? Caffeine? Sodium? Heck, artificial sweeteners? I don’t know; that’s what I’m asking.

I know of no credible evidence linking diet soda consumption to renal dysfunction.

And yes, I looked for such evidence.


Thanks, QtM.

If your kidneys are not already damaged, I don’t see how drinking diet pop would damage them further. Diet pop is high in phosphoric acid, and if you drink a lot of it the kidneys would have to work harder to get rid of all this phosphate. Drinking a lot of phosphate, in theory could also antagonize calcium and lead to kidney stones. However, in people with healthy kidneys and who do not have phosphate based stones, it certainly isn’t a major problem.

“An example of a food product that yields high levels of acid for the body to dispose of is a cola drink. Phosphoric acid is one of the ingredients listed on the cola container. The pH of cola is ~3.0, ranging from 2.8 to 3.2. The human kidney can excrete urine with a pH no lower than 5. If one ingests and fully absorbs a beverage with a pH of 3, one has to dilute it 100-fold to achieve a urinary pH of 5. Thus, a can containing 330 mL of cola would result in 33 L of urine! This does not happen because the body buffers the acid of the soft drink. For full buffering, 1 L of cola requires some four tablets of Tums, which contain 16 mEq of carbonate as the calcium salt.”


I can ask my nephrologist next week if you guys would like but I’m pretty confident that QtM would have known where to look.

While I’ve gotten a lot of advice about how to maintain good kidney health, since mine are already damaged by a chronic illness, I’ve never been told to avoid diet sodas. I’m sure anything in excessive quantities is bad for you but my biggest limits are on salt and protein.

How much of the acidity of soda comes from the CO2 dissolved in it? I would think that the pH would be mostly burped away, instead of leaching the minerals from the bloodstream…

While I’m not about to look up Ka’s at this hour of the night, I think more of the acidity comes from the phosphoric acid than the carbonated water, and thus burping doesn’t make much difference.