Recently we presented what we think of as The kidney stone diet, meaning a unitary diet platform suitable for idiopathic calcium stone formers in otherwise good health. The story of that diet and the implications it has for stone prevention deserve perhaps a bit more commentary than we allowed for in the original article.
The lovely image – Hendrick van Cleef, The Building of the Tower of Babel hangs in the Kröller-Müller Museum. He (1525 – 1589) is one of a family of famous painters and
The Narrow Winding Path
Over many decades, kidney stone researchers have gradually recognized what the ideal kidney stone diet might be. They did this mostly via normal science, the experimental testing of prevailing theory.
The way it happened, how our community gradually recognised the elements of a proper stone prevention diet, helps us understand where we are at today.
Here is a brief review sans references.
Calcium and Sodium
The very common idiopathic (genetic) hypercalciuria (IH) of calcium stone formers, only slowly gave up its secrets to three generations of excellent scientists. Early on, they recognized that intestinal calcium absorption was high. This led clinicians to try the effects of low calcium diet. The results were encouraging. Urine calcium excretion fell, and so did new stone formation. IH appeared to be a state of high calcium throughput from food into urine, easily and safely treated by low calcium diet.
But the bone disease of IH gradually became apparent. IH was not just a result of over-efficient calcium absorption but also of inefficient kidney calcium conservation, so bone mineral could be lost if diet calcium were not maintained. At first it appeared that IH might be of several kinds: Due to the intestine or due to the kidneys and intestine. We now know that intestine and kidney both play a role so one cannot safely reduce diet calcium as a treatment. A single trial of low calcium vs. ‘high’ calcium diet made the point very clear: Both lowered new stones but only the ‘high’ calcium diet did so lastingly over five years.
The secret was sodium restriction. With it, kidneys conserve calcium very well even in IH, so a ‘high’ calcium diet is safe. Eventually scientific and medical opinion came to favor a ‘high’ calcium – ‘low’ sodium diet.
The quotes are because we are in a time of change. The diets of many people even today hardly match contemporary recommendations, being lower in calcium and higher in sodium, so those recommendations can be viewed as high and low, respectively, compared to what is being done.
No one ever doubted the importance of urine oxalate in calcium oxalate stone formation or the benefit of lowering diet oxalate. But one group in particular pioneered in showing high calcium intake could permit a less stringent reduction in food oxalate yet keep urine oxalate within bounds This supported the benefits of high diet calcium although it did not at all diminish the importance of care about diet oxalate. Many think reciprocity between diet calcium and urine oxalate is a reason epidemiology has linked higher calcium intakes to a lower incidence of stones.
Diet protein in excess of that required for nitrogen balance raises urine calcium and decades of work concerned the mechanisms involved and whether or not high protein intake promotes bone mineral loss. This last issue remains unsettled as experts still joust with no clear winner. But the outcome for stone formers is neutral: Eating enough protein to maintain nitrogen balance is best for stone formers as for people in general.
Dr Jacob Lemann first showed the remarkable calciuric effects of simple sugars in normal people and that IH exaggerates the sugar effect. Sugars reduce kidney calcium conservation and so not only raise stone risk but could in principle deplete bone mineral. Even taken alone, his work is enough to warn stone formers with IH away from an excess of refined sugars.
The Royal Way
During our decades of labor those involved with the grand diseases of humankind were constructing their own final vision of what we should eat as a people.
To them, the need for diet calcium far in excess of normal behavior was glaring as they gazed on the massive burdens of osteoporosis.
Arguments of colossal scale and vituperation raged internationally over diet sodium as a cause of hypertension and over ‘low’ sodium vs. ‘normal’ sodium diets in treatment and prevention. Finally, much lower sodium than has been the norm won right of rule and the ponderous engines of government turned that way.
Sugar has been perhaps the last great battleground. The once ‘heart healthy’ high carbohydrate diet, tolerant of refined sugars as having little harm, has fallen into ignominy as a cause of rampant obesity and diabetes. Refined sugars now are shunned as unhealthy.
The Merging of the Choirs
And so it was as our small band fulfilled its quest for the right kidney stone diet, or, by way of metaphor, as we found the tune we wished to sing, we encountered not a passel of like sojourners but the massed choirs of the nations of the world, singing a like song in majestic chorale.
What we have called a ‘high’ calcium diet is not high now but merely proper. What we have called a ‘low’ sodium intake is not low, now, but merely proper. And sugar has become a demon in all eyes, dreadful to behold.
So, we stand among the ranks of the world’s anointed, and what we would say turns out to be what is said by all.
We Share the Kidney Stone Diet With the World
We have our kidney stone diet, which is more or less the right diet for healthy people, and it is our job to proliferate it as treatment for our patients.
The government and the societies have provided a richness of resources newly minted and our task now is to bring them into use for our patients.
Sums scarcely dreamed of in our world have been spent explicating for the American people the way to eat as we would want our patients to eat, and we need to help our patients use the resulting materials properly. Put another way, we have no reason as a community to await trials of low sodium intake, high calcium intake, low refined sugar intake, or low protein intakes: The prevailing relatively low calcium, high sodium, high sugar, and high protein diets are no longer viable alternatives for normal people and as physicians we must push against them with our kidney stone patients.
There is some exceptionalism about stone formers.
Response of IH to sodium and sugar is exaggerated, so the sodium intake of 1500 mg advised for high blood pressure may be better than the 2300 mg level advised as the upper limit for normal people. The need for enough calcium intake to prevent bone disease is perhaps more significant than in normal people because of IH.
Oxalate absorption may be abnormally high in some stone formers, which makes management of diet calcium and oxalate, and their timing with meals, unusually demanding.
Response of urine calcium to diet protein may be higher than in normals; this has not been tested well, but for the moment it means that very high protein intakes could be especially unwise.
So we need to promote the general ‘healthy people’ guidelines for treatment of our patients but with a few significant exceptions and points of special care.
Some of the Vast Resources
The FDA is the biggest. In it are massive amounts of diet information, portion sizes, meal plans, recipes, and materials for professionals. The DASH diet has long been advocated for higher calcium, lower sodium, and indirectly for less refined sugar. Being directed toward blood pressure management it has a large amount of nuts and seeds in it which may not always be ideal in relation to oxalate. The American Heart Association is another main source, albeit with a special emphasis. The American Diabetes Association can be mentioned although their site does not seem to emphasise diet calcium and sodium.
Many idiopathic calcium stone formers can and will use these resources and plan their diet calcium, sodium, protein, and sugar intakes with an understanding of the above mentioned special issues concerning stone formation.
But many will not be able to do this. It is no small matter to translate the mass of information into real change of eating habits.
Some may be enabled by sites like this one, or by handouts and perhaps books, and need nothing more.
Some may need additional education beyond what books and websites can provide.
Some may require one on one nursing or nutritional counseling to solve their specific problems.
A few will require that physicians themselves enter into the details of diet management.
How Will We Make Up the Difference?
Some physicians may use combinations of handouts with brief nursing or nutritionist time to provide basic educational support.
When one on one detailed nursing or nutritionist education is needed patients will usually have to expect additional out of pocket costs depending upon insurance carriers.
We who write this have vast experience with the problem of stone prevention, one as a physician the other during a decade of work at Litholink and years of private practice consultation. From our experience we believe a scalable approach will require that some in nursing and some nutrition practitioners take a special interest in understanding stone disease prevention and add to their professional qualifications requisite additional expertise.
Support group structures may be beneficial.
There is no longer any reason to wait concerning the right diet for kidney stone patients. We know the answer. It is time to do it.
I (Jill), have recently put together a private FB page called THE Kidney Stone Diet. It is a group that helps educate you on your physician prescribed treatment plans. I moderate it to keep it clinically sound. Come on over and join the discussion!
46 Responses to “HOW TO EAT THE KIDNEY STONE DIET”
I have come upon your articles when trying to gain understanding of the lab results of my 24 hour urine test, prior to a visit with my urologist, mostly so I could ask good questions. Much of what I read makes sense to me.
I have calcium oxalate stones, and my calcium level was 342 in September of 2022. At that time, medications were suggested (indapamide and potassium chloride). I resisted, and we decided to stop taking my calcium supplement and only get dietary calcium, and recheck calcium levels in a few months. As a 66 year old female, with diagnosed osteopenia, I was careful to get as close to 1200 mg of dietary calcium daily (and on occasion, I would take one 600 mg + D, (with food) if I could see that I would not get enough in my diet that day. In February 2023, I retested and my calcium level had gone up to 475! I have a followup appointment soon to discuss course of action. Do the medications I mentioned earlier make sense to you? (I have been primarily asympomatic with regard to trouble with the kidney stones…I passed a small one about 3 years ago, and CT scans show multiple stones in both kidneys currently, but produce no symptoms.) I understand that sodium intake should also be limited…what is the proper amount of sodium I should get in my diet? <1500 mg? Thank you so much for your attention. Your articles have been a godsend to me!
Fredric Coe, MD
Hi Lynn, You do not mention the amount of sodium in the 24 hour urine. It is central. I suspect sodium intake went up with your diet calcium. Since you have bone disease and stones and high urine calcium perhaps your physicians and you might go a bit further and consider one of two alternative strategies. One would be thiazide (chlorthalidone or indapamide) to control stone risk and improve bone mineral balance. Another would be a bisphosphonate for bone with might also lower urine calcium. These are merely ideas for your physicians to discuss with you if they consider them helpful. As for sodium, you have it right. Regards, Fred Coe
Dr. Coe, In regards to the question about sodium in the 24 hour test, it did indeed go up from 78 in September 2022 to 136 in February 2023. (Although, still <200 standard range) Chloride also went up from 61 to 165 in that time frame. Potassium also went up from 54 to 87. My doctor has prescribed indapamide along with potassium citrate [rather than potassium chloride, I think because of the chloride increase, and a decrease in citric acid (829 to 671) in the two tests]. We will repeat the 24 urine test in 4 months to check levels again. As an aside, I told my doctor about finding your site, and asked if she had heard of you. Her response was very enthusiastic, as she attended the University of Chicago and she was your student. She practices at UTSouthwestern in Dallas.
Thank you again for your attention, Lynn
Fredric Coe, MD
Hi Lynn, Glad that you have a physician at an excellent stone center. Stay with her. Best, Fred
Hello Dr. Coe, I’m resending this question that I submitted on Dec 7, 2022 since I don’t see a response and you have answered other questions from people since so I believe it just never got to you.
Do Phytates (Phytic Acid) have any effect on stone formation? I’ve read that they can decrease absorption of calcium and magnesium. If you are someone that eats a lot of whole grains, nuts, and legumes will that cause the calcium that you eat to be less likely to get absorbed and increase urine calcium?
Fredric Coe, MD
Hi Diane, First, I am sorry about my late answer. A PubMed search for phytate AND kidney stones retrieved about 30 papers of which this one is most recent and done by skilled scientists. It is also typical of the present knowledge base. In a well done but small population study: “In fully adjusted analyses, lower dietary calcium, potassium, caffeine, phytate, and fluid intake were all associated with a higher odds of an incident symptomatic kidney stone.”This means that less diet phytate is among 5 factors that associate with new stone formation. Of the 5, low diet calcium, potassium, and fluid are amply covered on this site. Drs Rule and Taylor are excellent epidemiologists and therefore explored which of these retain independent predictive power for new stone set when results are adjusted for all other factors, and in this case only urine calcium retained power. So one can say in general low diet phytate associates with new stone onset but that phytate intake is itself associated with diet potassium (fruits and veggies) and fluids (veggies have more water in them) so it does not itself have independent effects. As for actual treatment trial data, there are none. Eat your fruits and veggies, and you will get the phytate effect they found. The other papers add nothing more, so far as I can tell. Regards, Fred Coe
I can’t seem to locate the kidney stone diet. It says it is not open to the public. Can someone help me? Thank you in advance.
Fredric L Coe, MD
Hi Mary, The article on the diet is the one you wrote on. If you want help in putting a diet together, the ideal person is Jill Harris who works online with patients like yourself. Regards, Fred Coe
my oxalate was 10% and calcuim phosporus was 90% labs where all normal my urinure was in the middle range. when I left the doctor after I got my stent removed she said I didnt need to see a kidney speciallist. I still think I need to watch what i eat. what would you recomend. no one can steer me in the right direction this is the second time I have had stones.
Fredric L Coe, MD
Hi Joel, I gather your stone was 10% calcium oxalate and 90% calcium phosphate, making you a calcium phosphate stone former. I doubt your 24 hour urine studies could be mid range normal, but if they are then something caused this kind of stone and is now somehow in abeyance. For example phosphate stones form because urine is unduly alkaline, pH >6.3. Regards, Fred Coe
If you are able to advise thank you so much. I noticed dark sand looking sediment in my 4 y.o. daughter 2 wks after potty training. No regular symptoms (although history of severe reactive arthritis at 2 y.o). There was a one time horrible day a week prior to noticing sediment of extreme joint pain, fever and chills.
Nephrologist said high urine ph and amorphous calcium phosphate crystals.
By next visit ph was normal but 12hour urine collection showed low urine output and high oxalate excretion. US was normal for complete abdominal.
The doctor is having me increase water, go on low oxalate and repeat urine collection in 1 month. Then test for primary hyperoxaluria. I am praying it’s not that, are there any other things it could be that would cause my otherwise healthy 4 y o to have high oxalate and crystals in her urine? It seems too coincidental to be 2 wks after potty training.
Fredric L Coe, MD
Hi Sandra, the crystals are calcium phosphate, the chemistry shows high oxalate – but what about urine calcium? Urine values need to be specially calculated for young children so be sure the urine is done at Litholink (they have proper pediatric corrections) or another lab that does this. Of course, testing for PH1 is genetic and harmless, and very exact in most cases, so it is worth doing. Regards, Fred Coe
Wendy L Tristan
I was in the hospital for a staghorn stone in the left kidney.the urologist placed a stent to let the urine flow from the kidney.
I had been drinking the cranberry juice, pineapple juice, lots of water, lemon water.The juices raised my blood sugar level
way high.I do have a calcium rich diet.The urologist did not talk to me after the stent was put in. I was given papers upon release from the hospital.I was looking on line for more informatrion of ways to help myself. I am prone to kidney stones every few years, I always passed those stones .This one was way different. I even was drinking the apple cider vinager Thank you for this article .I
Fredric L Coe, MD
Hi Wendy, a PERC is major surgery and prevention very important. Here is my best introduction on how to be sure about what is causing stones, and how to prevent more. Regards, Fred Coe
Dr. Coe, do you have any calcium phosphate diet parameters?
Fredric L Coe, MD
Hi Heather, Calcium phosphate stones are harder to prevent, and while lower diet sodium and more fluids are always a good thing I favor adding low dose thiazide. Phosphate stones grow faster and larger than calcium oxalate stones, and prevention is more urgent. Regards, Fred Coe
My husband had a uric acid kidney stone and was told to eat a diet low in purine. I don’t see uric acid stones mentioned in your article or in the kidney stone diet. Are the dietary recommendations the same as that for a calcium stone? If not, will you provide some resources that address uric acid stones?
The moderate amount of protein listed in The Kidney Stone Diet will help him lower his uric acid amounts and increase his urine pH. You can look at the articles here on uric acid stones.https://kidneystones.uchicago.edu/chapter-seven-uric-acid-stones/
There are other foods that can cause uric acid stones as well bc of their high purine level. Mayo clinic has that list here:https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/gout-diet/art-20048524
Hope this helps, Jill
Fredric L Coe, MD
Hi Laura, diet is not important for uric acid stones. Urine pH is too low and treatment requires supplemental alkali. Here is a good article on uric acid stones. Regards, Fred Coe
Don’t do facebook, any way to get a copy of the kidney stone diet?
Fredric Coe, MD
Hi cdouglas, The diet is essentially the ideal US diet with a few add ons. Here is the main article. There is no simple menu as the diet is not simple but rather a set of parameters within which one can fashion more or less an infinite array of meals. Regards, Fred Coe
Just received my stone analysis – I guessed right by visual examination – calcium oxylate di and mono. I had an awful experience with lithotripsy, kinked ureter, hydronephrosis, stent, ulcer from meds, etc.
Here is my problem: due to ulcers I cannot eat citrus, mint, tomato, vinegar, vitamins, pills, etc. And I almost never meet my protein macros every day (I try to use egg whites to up my protein). I am also vitamin b and d deficient at this time, as well as borderline on my bone density test.
How do I get all the needed nutrition with all the limitations I have? I have some success with vitamin patches, so I will continue those, but my diet restrictions are suffocating. I did not drink much water at all previously because I would have to use the bathroom so much, so I am hoping my increase in water intake helps significantly. I am assuming that a normal protein intake is OK, not just a high one. Am I correct? Any other advice? on the other hand, I can’t seem to get my gut back to normal since the birth of my child who is now a teenager!
Fredric Coe, MD
Hi Jeanette, I gather that ulcer disease has impinged on your diet and urinary frequency on your fluid intake. To me your main problem is a better solution to your GI problems so you can eat a more normal diet. Obviously, you would also be served by kidney stone testing to be sure what is really causing the stones. Here is a plan for the latter. For the former, nothing will suffice but a skilled gastroenterologist. Regards, Fred Coe
Thanks, it’s been tough.