Some Practical Information about Kidney Stones
There is a lot of information on the web about kidney stones, the treatment of patients who suffer from them, and their prevention. Recent research studies and scientific discoveries offer significant progress (and hope!) in reducing the formation and re-occurrence of those awful little rocks.
First, though, a disclaimer: I am not a doctor. The information contained on these pages has been collected by my own interest because I am a four-time stone sufferer over the last seven years. Although I've had excellent care from my urologist, I wanted to find out everything I could about preventing further occurrences as well as learn about what research has been done and what new treatments are on the horizon.
My history with stones:
| First instance -- January, 1995. Ended up in hospital at 5 A.M. with moderate pain. It took about two months with bi-weekly bouts of mild-to-moderate pain to pass the stone. |
| Second instance -- March, 1998(?). Stone stuck at exit of kidney. Too large to pass, so I had a successful ESWL (Lithotripsy) to break the stone up. |
| Third instance -- 2001. Stone stuck at exit of kidney, waited a few weeks to see if it would progress, but it did not. ESWL again, but not very successful, it caused more harm than good. Stone still had to work its way out, but it made it out about 4-5 weeks later. ESWL caused some scarring, so it may no longer be an option in that kidney if I have future stones. |
| Fourth instance -- March-May, 2002. 6mm x 5mm Stone stuck mid-ureter, x-ray visualization was occluded by bone so ESWL was not an option. Tried ureteroscopy to grab it, but it was embedded and could not be removed. Stent was inserted and removed a week later and it evidently dilated ureter enough to enable stone to pass spontaneously on May 10th, 2002. Pictures of stone: SVGA, larger resolution (2048x1536), SVGA zoomed out for scale. Thanks to Tim Thompson for letting me borrow his new Nikon Coolpix 995. |
All my stones have been calcium-oxalate stones similar to the stones that occur in 80% of people that suffer from kidney stones. The information on this site pertains only to those that know they have calcium-oxalate stones.
I am by no means an expert. What I know is from my own personal experience, research, and curiosity. This information is here to inform you about stones in a manner that is clear and understandable in hopes that you can learn from it and help prevent you from having kidney stones (or more attacks!). I have a broad interest in science, but am not a medical professional, researcher, or biologist. Any information here is to be taken and used at YOUR OWN RISK, and the author cannot be held liable for any harm, direct, or indirect, intentional, or not, based on the information on these pages.
Another note: This information is compiled by myself. There is a lot of information out there, even provided by doctors, which I believe is either outdated or sometimes incomplete. My goal is to provide relevant information that is practical and compile it so that you can have a good understanding of stones, prevention, and treatment. I have drawn my own conclusions about some things, mainly based on recent research and discoveries, and by no means is this a complete discussion about kidney stones, it is only my small contribution to the collective knowledge. So it's best to treat this information as though you heard it at the office, or at a party, or from a news report on TV. Discuss it with your doctor if you have any questions, as he/she is the professional and can offer expert advice and treatment. This information may or may not apply to you.
How do stones form?
Calcium oxalate stones form when excessive amounts of oxalates make it to the kidneys and pass into the urine. Once in the kidney, oxalates bind with free calcium to form stones. Over time, the stones enlarge, break free from inside the kidney (the calyces), and head for the ureter to be washed into the bladder and then eliminated. If the stones are too big, well, you have a problem. They can partially or completely block the exit to the ureter or get stuck along the way, causing renal colic, which is the often intense pain that first-time sufferers hope to never suffer again. Sometimes the stones get stuck between the bladder and the way out, but that's never happened to anyone I know so I don't know what that's like.
For a long time the primary focus of stone formation has been on the amount of calcium that makes it to your kidneys. For this reason, doctors would put their patients on low calcium diets to try to reduce their recurrence. Recent research has discovered that it's not the calcium, it's the oxalates that are the culprits. In fact, putting yourself on a low-calcium diet can actually increase the chance of recurrence (and also contributes to all sorts of calcium deficiency-related diseases like osteoporosis). A recent research study has some very interesting results about how diet affects the formation of stones. Read this PDF document, especially the sections about calcium, oxalates, and fluid intake. More on that later.
Where do the oxalates come from?
Oxalates are compounds found in a variety of foods. Here is an excellent table of the oxalate levels in certain foods.
Yeah, I eat that stuff, so what's the problem? Why do some folks get stones and others don't?
This is the kicker and probably the most exciting area of recent research.
There are two probable causes which I'll focus on here. There are several other reasons why people get stones, but I'll bet that many folks can attribute their stones to one (or both) of these causes, based on the research I've read:
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Oxalate-rich foods consumed without calcium |
When oxalate-rich foods are consumed, if there is calcium present in the digestive tract (a.k.a. gut or intestines), the oxalates will combine with the calcium there and be eliminated along with the rest of the waste. If there is no calcium present in the gut (and no o. formigenes, see below), the oxalates will make their way to the kidneys where they are more likely to get with the calcium there and form stones.
In other words, If calcium-rich foods or drinks are consumed at the same time as the oxalate-rich food, then the oxalates are more likely to bind with them in the gut and not make it to the kidney and cause problems. In the study linked above, they made an interesting observation in that someone who ate milk chocolate bars for several days did not show an increase in the presence of oxalates in the urine, despite chocolate being one of the higher oxalate-containing foods. They surmise that because milk chocolate contains calcium (milk), the oxalates combined with that calcium in the gut and never made it to the kidneys.
Another patient was put on a severe calcium-restricted diet and soon showed significantly increased levels of oxalates in the urine, which is a bad thing. So a low-calcium diet is counter-productive. A low-oxalate diet is best, or at least a diet that includes some dietary calcium is okay. Note that taking calcium supplements was deemed to not be effective, because the supplements are not usually taken during a meal, thus the calcium will not be in the vicinity of the oxalate-containing foods and never has a chance to be combined with the oxalates and be eliminated in the gut.
So folks that enjoy their beetroot (blech!), swiss chard, spinach, or rhubarb pie and eat deep, rich (non-milk) chocolate desserts and avoid calcium in their diet are at a high risk.
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There is a bacteria, oxalobacter formigenes, that breaks down oxalates in the gut. This bacteria is naturally occurring, and in studies of children, nearly all children naturally acquire this bacteria by the age 6-8. However, the vast majority of patients with recurring calcium oxalate stones no longer have this bacteria present in their gut. It turns out that this bacteria is very easily killed by most antibiotics that are prescribed for everyday infections. Once killed, it's not very easy for an adult to recolonize this bacteria in the gut. Unlike acidophilus, o. formigenes cannot be purchased at your local supermarket and reestablished through common means. O. formigenes seems to occur in lake sediment. Why kids get this in their gut I don't know...anybody have any theories? Perhaps it's the mud pies that kids make....Anyway, here's a good article that sums up the story on this bacteria, and there are lots of other medical articles (like this and this) about the role of o. formigenes in metabolizing oxalates. There is a company, Ixion-Biotech, working with researchers at the University of Florida to figure out ways to use this bacteria, or the actual enzyme within this bacteria, to absorb oxalates in the gut and thereby prevent them from being transferred to the bloodstream and urine. One method is to pop tablets jam-packed with the bacteria in hopes that it will recolonize itself back in your gut. This is like a one-shot deal...take a few pills, verify that the o. formigenes colony has been reestablished in the gut, then you're all set (but be sure to not take antibiotics or you'll have to start over). Or, another way is to take a (daily?) pill with just the enzyme that will work with your meals as you digest them. However, I guess you'd have to continually take the enzyme because it doesn't actually take hold in your gut like the bacteria form would. Hmm...wonder which option the drug companies will prefer.... I have been in contact with one of the key people who has developed the research on o. formigenes and is heading up many of the clinical trials associated with these treatments. We may see something available on the market in the next few years, if all goes well.
As a side note, the processing power (or lack of it) of o. formigenes is not just a problem for humans -- it's also a problem for livestock like cattle, sheep, and goats, and even pets like dogs and cats! Seems that all the antibiotics that have cropped up in the last 50 years have caused a widespread epidemic of stones in humans and domesticated animals. There are actually a lot of studies that have shown a dramatic increase in stone occurrences in western civilizations since World War II...however until recently, no one really had a solid theory as to why. However many now believe it has coincided with the introduction of antibiotics into modern medicine. The antibiotics kill o. formigenes and allow the stones to form.
So what can I do right now to help stop the formation of stones and prevent a recurrence?
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Talk to your doctor about this information. See if he/she has been following this type of research. See if it may apply to you. If possible, have your stone analyzed to see if it is composed of calcium oxalates. |
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Drink plenty of fluids!!! This is, without a doubt, the most sure-fire way to reduce the occurrence of stones. |
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Avoid oxalate-rich foods, or if you occasionally indulge in them, be sure to consume lots of dietary calcium at the same time. |
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Avoid grapefruit juice. They don't know why, but in some studies, it has been attributed to a significant increased risk of stones. A friend of mine used to drink a quart of grapefruit juice every morning. In a short time he had a very painful stone episode. |
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Watch your protein and salt intake. A recent study has shown that people with high-protein and high-salt (sodium) diets have an increased risk of stones. This study also indicated that a decrease in calcium increased the amount of urinary oxalates. |
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Reconsider the advice to reduce your calcium intake. Several recent studies, including this excellent one, indicate that "Normal dietary calcium intake, along with reduced salt and protein, is now advised.¹" |
Other sources:
Kidney Stones, symptoms, treatment
Please let me know if you have any comments on this information
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Last Edited:
December 27, 2006
