Some commonly held beliefs about kidney stones can be considered myths, without any supporting evidence. Other beliefs we consider controversial and are likely to also be incorrect based on expert opinion.
Myth 1. I got a kidney stone because of my calcium intake.
Despite the fact that calcium is a major component of 75% of stones, excessive calcium intake is very rarely the cause of stone formation. In fact, several studies have shown that restricting calcium intake in most stone formers actually increases the number of stones they develop. Find out more on our page on calcium intake.
Myth 2. I can take something to dissolve my stones*
This myth has an asterisk because it is actually true in select cases.
For the majority of stones formers, including those with calcium oxalate and calcium phosphate stones (80% of stones), there is no medication available that can successfully dissolve their stones.
In select patients with uric acid stones (5-7% of stones) or cystine stones (1-3% of stones), medications can potentially be used to help dissolve their stones. However, even in these cases, surgery is still sometimes required to remove or treat the stones.
Myth 3. Cranberry juice will help me prevent stones.
While cranberry juice can help in the prevention of recurrent urinary tract infections, it does not seem to have an overall beneficial effect for stone formers. Instead, ingestion of cranberry juice results in a mixed effect on urinary factors which probably leads to no benefit or potentially increased stone risk for most patients (Gettman et al, J Urol, 2005).
Myth 4. Drinking this olive oil and lemon juice will help lubricate my stone and help it pass.
Besides sounding awful tasting, we are not aware of any studies showing that drinking this combination (or other similar home remedies) can improve stone passage. There are however some medications that have been shown to speed stone passage in randomized studies.
Stones are actually more common than most people realize. 1 in every 11 Americans will experience a stone in their lifetime.
Myth 6. Water is the only fluid useful to help prevent stones.
Research suggests that it is the volume of fluid you drink that is most important, not the type of fluid. Some fluids previously felt to increase stone risk (tea, coffee, beer) actually seem to decrease risk. Cola drinking also doesn’t seem to increase risk. We talk about it more below. The bottom line for those trying to keep their fluid intake up is that for the most part you can drink what you want.
Myth 7. Kidney stones are related to gallbladder stones (gallstones).
Although both are considered stones and have the word “bladder” associated with them, gallstones and kidney stones are not in any way related.
Myth 8. I shouldn’t be getting kidney stones because no one in my family has had them.
While those with a family history of stones are at 2.5 times greater risk of forming a stone than individuals without a family history, the majority of new stone formers actually do not have family history.
Controversy 1. My soda drinking is causing me to form stones.
The belief that soda drinking is associated with increased kidney stone formation is supported by a study of 1,009 males randomized to refrain from or continue 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 (Coca Cola) while citric acid is most commonly used in fruit flavored sodas (Sprite). Based on this study, avoidance of cola drinks is recommended by some physicians as a way to avoid stones.
More recent 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. The authors found that cola intake did increase stone risk but that this appeared to be because individuals with higher cola intake also has other dietary factors that would increase their stone risk. 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 cola drinking seems to be mixed. Kidney stoners who want to play it safe might want to avoid colas and choose other beverages. They can also choose colas which don’t use phosphoric acid. (You can check this by reading the ingredients list on the side of the bottle or can). Some brands we’ve found that don’t use phosphoric acid include Pepsi Natural and Red Bull Cola.
Controversy 2. The bad (hard) tap water in my town is causing my stones.
It seems intuitive that drinking “hard” tap water, which contains more dissolved minerals (such as calcium and magnesium), might increase stone risk. However, most studies on the subject show that the type of tap water (hard versus soft) either doesn’t seem to make a difference or that soft water, and not hard water, is actually associated with increased stone risk (Schwartz et al, Urology, 2002).
Based on available research, the quality and source of your tap water likely makes little or no impact on stone risk. Putting in a water softener system may actually increase your risk! We like drinking filtered water, but only because it improves the taste.