If we put together everything on this site about diet for kidney stone prevention we get a reasonable and consistent image of one basic pattern. It is more or less what is ideal for idiopathic hypercalciuria and for reducing urine oxalate. It is the diet that has been used in the one major trial of diet for stone prevention. It accords with modern recommendations for the health of the American people. More or less, after all is said, there is only one diet plan that meets the needs for kidney stone prevention and we have called it ‘The Kidney Stone Diet.’
‘We’ are me and Jill Harris (pictured right).
Of course, we are speaking of the diet for treatment of idiopathic calcium stones. Stones from systemic diseases, like bowel disease, primary hyperparathyroidism, primary hyperoxaluria, are treated by treating those diseases, and that is a different matter altogether. But those are the exceptions. Of the millions of American people with stones, almost all are idiopathic.
There will be surprises. Diet oxalate always matters but less so than you might think once the full diet is in place. Calcium will seem odd to you unless you have been a frequenter of this site. Sodium will seem all too familiar.
Dissecting the Diet
High calcium intake is essential for stone formers. They have bones and many have idiopathic hypercalciuria that can cause bone disease unless there is a lot of diet calcium intake. Oxalate absorption is greatly hampered by high calcium intake, if the calcium is eaten when the oxalate is eaten.
It is not only stone formers who need a lot of calcium. The new FDA diet recommendations include high calcium intake for all Americans.
How high is high?
More or less, throughout life, men or women, girls or boys, the range hovers between 1,000 and 1,200 mg daily. This amount of calcium is ideal for both protection against bone mineral loss from idiopathic hypercalciuria and reducing oxalate absorption. The unique part for stone formers is timing the calcium to go with the main oxalate containing foods during the day.
Urine calcium follows urine sodium like a shadow. The lower the sodium the lower the calcium. In the one bone study that seriously looked at the matter, it was the combination of low sodium diet and high calcium diet that led to positive bone calcium balance – uptake of mineral into bone as opposed to bone loss.
So, what is ‘low sodium. The new FDA recommendations are an intake below 2300 mg (100 mEq for those of you who read lab reports). For those with high blood pressure – treated with drugs or not – 1,500 mg is ideal. For stone formers, the latter, 1,500 is ideal because it brings urine calcium of hypercalciuric people near the normal range, and also benefits those without hypercalciuria by making urine calcium as low as possible.
If 1,500 mg is the ideal for the kidney stone diet, 2,300 is the absolute upper limit, and people will more or less want to live somewhere in between, hopefully at the low end.
Refined sugar is sugar that has been extracted from plants into the white stuff you buy in bulk and add to cake and cookie and brownie recipes, and use to make candy. The sugar in plants and fruits is packaged along with fiber and released slowly so it is very safe. Once you extract it into white powder it is absorbed very fast. We are not made to use this well. Blood sugar and insulin rise a lot, fat is formed, and it is not healthy.
Jack Lemann first showed decades ago that simply eating 100 gm of glucose causes a rapid rise in urine calcium with – can you imagine worse? – a concomitant fall in urine volume so supersaturations rise extremely high. It is the perfect storm. Urine calcium of people with hypercalciuria rises a lot more than in those without it, so it is evil in family members of stone formers. Since about one half of the relatives of a hypercalciuric stone former will be hypercalciuric because of genetics, even the children are put at risk by high sugar intakes. The worst part is that hypercalciuria is silent until stones or crystals form, so no one can know.
Very reduced refined sugar intake is emphasized in the new government diet recommendations because of American obesity and diabetes. The recommendation is that less than 10% of all diet carbohydrates come in the form of added sugar which means very little sweets. This means sugars that are added to foods, not the natural sugars in fruits and some vegetables. The latter are absorbed more slowly and are safe. Obviously candy and cake and brownies and all the other good stuff is in the very bad category.
Our long and difficult review of the protein story make a main point. People absolutely need at least 0.8 gm/day per kilogram of body weight of protein and need no more than 1 gm/d/kg. WIthin that narrow range there is a measurable but modest effect of protein on urine calcium that can be neglected if sodium is controlled. So we see no physiological basis or trial evidence that ‘low protein diet’ is appropriate. By low we could only mean 0.8gm/kg/d. The one comprehensive kidney stone diet trial implies a low protein intake but in fact employed 93 gm of diet protein – which is a lot. The diet change was to make 40% of it be plant based. But there is no evidence that plant protein reduces stones or urine calcium compared to meat protein. Plant based protein sources are often rich in oxalate.
All things being equal we have advocated for a low oxalate intake between 50 and 100 mg daily. However Ross Holmes showed clearly that with very high calcium intakes such as 1,000 to 1,200 mg daily, absorption of diet oxalate is less and therefore the need for strict control is also less. In the one diet trial by Borghi diet oxalate was 200 mg/day but diet calcium was high and urine oxalate actually lower than in his contrast group with low calcium diet and less oxalate intake.
The ideal approach as best we can tell is to put in place the high calcium diet, aim for about 200 mg of oxalate, which is easier to accomplish than lower values, and measure the urine results. If despite high calcium intake urine oxalate is creating risk of stones then diet needs to be altered appropriately.
Some people seem to absorb oxalate more efficiently than others, so there are no fixed rules. Many have normal urine oxalate excretions without any diet change at all. Many who have undesirably high urine oxalate at their first labs will show a marked fall with the higher calcium intake and need no further restrictions.
Some will remain hyperoxaluric despite the calcium and it is for them that very restricted oxalate diets can be reserved.
One key is urine collections to see that calcium alone can accomplish for any one person.
The other key is timing. The diet calcium must come in the same meals that contain the bulk of the day’s oxalate. Without that precaution calcium might not work well in this regard.
We have covered this topic completely. The urine volume you want is above 2.5 l/d, the amount of fluids needed is about 3 l/d and you just have to experiment to find the exact intake for you, and also allow for weather, occupation, sports. Obviously sugared fluids have always been unfavored on this site, and you need to avoid them. The other major issue is steadiness over the day and into the evening. Overnight we just take our chances in most cases.
There You Have It
The kidney stone diet is one thing: High calcium, low sodium, low refined sugar, normal protein, flexible oxalate management that depends on how high urine oxalate is once high diet calcium is achieved, and of course high fluids.
This site is rich in articles that pertain to the kidney stone diet – it was built in part for this purpose. The home page lists articles by topic and you can find there the ones you need. Here is a brief summary with links.
High calcium and low sodium: 1,000 to 1,200 mg calcium 65 – 100 mEq (1,500 to 2,300 mg) sodium and care about oxalate (50 to 200 mg/day) can be achieved using our list of foods that meet all three requirements. It is essential that calcium be taken in with the meals that contain appreciable oxalate.
Low refined sugar (below 10% of daily carbohydrate intake): This is best thought of as a major reduction in sweets – cookies, candy, sugared drinks, cake, pie. Fruits are not a problem, but smoothies that break up the fruit may liberate their sugars and overcome the ‘slow release’ properties of the intact fruits themselves. We did not write an article about this matter because it is simply to give up what many of us love.
Normal protein intake – this translates into 1/2 to 2/3 pound of meats daily for an average adult. For stones, the issue of red meat vs. fish or chicken does not matter. Vegetable protein sources such as soy are high enough in oxalate one cannot recommend them.
High fluids and how to get them are in many articles on this site.
When Do You Begin the Diet
To us there is no question it should be after even one stone. The diet accords with all modern recommendations. The only special features are attention to oxalate and to timing of calcium with oxalate containing foods. High Fluids are more of a task, but after one stone the one trial showed a marked reduction in second stone formation with urine volumes above 2.5 l/day compared to the 1 l/d of the control group.
A more subtle matter is family members. Idiopathic hypercalciuria causes both stones and bone disease, and is hereditary. About half of first degree relatives of hypercalciuric people with stones have the trait even without stones. Given this, and also that the kidney stone diet is benign and in line with what we all should be eating, why not make it the general family diet as well?
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!
407 Responses to “THE KIDNEY STONE DIET”
Rev. Dr. Robert Santucci
Good morning Dr. Cole and Jill,
Thank you both for your information and passing on your immense knowledge in this field. I have two chronic diseases colliding at the same time. For the last 17 years I have been forming calcium oxalate stones and have persistent tingling and numbness in my feet which I have been diagnosed with peripheral neuropathy. For the stones, I take 4oz. of lemon juice daily as a preventive measure.
To be brief, can you both suggest a diet or links that empathizes low oxalate and anti inflammatory foods to not trigger kidney stones or my PN? Thank you in advance for your consideration and blessings to the both of you.
Rev. Dr. Robert C. Santucci
Fredric Coe, MD
Hi Rev. Santucci, I know of no obvious cause linking peripheral neuropathy to calcium stones, and profoundly doubt that oxalate – the molecule – is a cause of neuropathy in a person with normal or near normal kidney function. I would suggest full evaluation for the cause of your stones. Even if urine oxalate is elevated and a prime driver of stone disease I would not be able to connect it to neuropathy unless the elevation was very marked. Lemon juice has somehow emerged as a seeming general remedy for stones, and that is not the case. It is merely a source of alkali, and that could be beneficial or otherwise. Regards, Fred Coe
Hi Prof. Coe,
As I am lactose intolerant I am using milk alternatives like fortified oat milk to boost my calcium intake.
Without this included my daily intake via diet is an average of 300-400mg.
Lately the milk alternatives have been giving me gastrointestinal issues like bloating.
Being that I also have Hypocitraturia (taking citrate for it) I was wondering if calcium citrate supplement at mealtimes could be a viable
option instead of the fortified oat milk? (My stone was a Ca Oxalate stone formed around 5-6 years ago).
Fredric Coe, MD
Hi Ric, calcium citrate can be a way to get extra calcium, and does include citrate. Whether it will maintain your urine citrate and not pose to excessive a calcium loss is best determined by 24 hour testing while using it. Another approach is to look at the label and determine the amount of calcium citrate per dose and calculate the amount of citrate (potassium citrate pills contain 10 mEq of citrate in a single dose, and usually 2 doses are enough to increase urine citrate). You would need the molecular weight of the calcium citrate salt in the product which one can find on Google. Regards, Fred Coe
Dear Dr. Coe,
I very much appreciate you sharing your expertise. I visited the U of Chicago once-it is a beautiful place!
I had a ureteroscopy 6 months ago and the stone was 1 cm. My urologist offered no post-operative care and it took me 6 months to finally get the stone composition, from a 1 mm piece, after an official request for records. I am angry I have wasted all this time not knowing what I should be doing. The compostition was: Calcium Oxalate Dihydrate-25%, Calcium Oxalate Monohydrate-50%, Carbonate Apatite-25%.
I will be getting a new urologist. In the meantime, should I go with the dietary recommendations above? I do still have smaller stones. Should I take a “stonebreaker” supplement?
I’m on Long Island. I am 55 yrs. old. Thank you so much.
Fredric L Coe, MD
Hi FLorence, There is considerable phosphate in your stone so I would proceed only on the basis of complete evaluation. I would guess urine calcium and pH will be high, but guessing does not make it so. As for the stonebreakers, that is a name without meaning as there is no such think presently known on Earth or in heaven. Regards, Fred Coe
I might suggest that the material here be more easily printable. Or have it in the form of a small book which can be purchased. I will be doing the prevention course with Ms. Harris and am very excited about it.
Thanks so much. It is a privilege to have access to someone of your expertise.
One more thing. There is a great opportunity to create products for stone formers like snack bars, frozen foods, etc. I am trying to keep track of sodium now and counting milligrams all day in addition to having other diet limitations is making me a little crazy.
I have a snack book for kidney stone formers. All the oxalate, calcium, salt and sugar figured out and kidney stone diet compliant!
Hi Dr. Coe,
Thank you very much for all the helpful info you have.
I am 55 and had kidney stone issues for last 25 years. I had 7 incidents and three of them required procedures. The last one required multiple procedures (lithotripsy and uretoscopy). In the past, stones were calcium oxalate. Recently the sone was
Hydroxyl Apatite with a small portion of Calcium Oxalate
My 24 hour of urine test shows:
Calcium: 300 mg
Oxalate: 29 mg
Uric acid: 490 mg
Citrate: 702 mg
Sodium: 216 mg
Maganisum: 125 mg
Ammonia: 28 mEq
Pottasium: 47 mEq
Creatinine: 1166 mg
Calcium oxalate: 1.38
BRUSHITE RELATIVE: 2.61
SODIUM URATE RELATIVE SUPERSATURATION: 1.60
STRUVITE RELATIVE SUPERSATURATION: 3.82
URIC ACID RELATIVE: 0.13
I reduced or eliminated high oxalate food on my own.
My doctor advised to reduce salt and calcium after this result.
I do have another 5 mm stone on other side (kidney).
Any other suggestions to prevent the stones.
Stone was bigger 9mm this time and I assume it was hard to break as the lithotripsy didn’t really reduce the size much.
Fredric L Coe, MD
Hi Jayesh, You have high urine calcium and pH and high SS for calcium phosphate (your present stone). Less diet sodium (1500 to 2000 mg/d) is a good idea. But given many stones I would add chlorthalidone 25 mg/d to lower urine pH and calcium even further as calcium phosphate stones can form rapidly and grow. Regards, Fred Coe
I am having kidney stone from 2014 with stone formation after every two years. But from last one year I am getting kidney stone after every one or two months. I have done below tests
Ph – 6.0
Calcium – 45.3 mg/24 hrs
Uric acid – 412 mg/24 hrs
Urinary Citrate – 461.4 mg/24 hrs
Urinary phosphorus – 696.3 mg/24 hrs
Urine oxalate – 19 mg mg/24 hrs
Calcium Serum – 9.6 mg/dl
Pth – 26.40 pg/ml
Creatinine – 0.8
Uric acid – 8.3 mg/dl
Electrolytes are within normal limits
I have fatty liver and bit high Chlestrol
No diabetes or hypertension
Till now I am failed to find the cause of repetitive kidney stone and they are forming very fast.
Fredric Coe, MD
Hi Sahil, You do not say what the stones are made of. Your urine calcium is very low, as is oxalate, so I am suspicious they are made of uric acid. Of highest importance, have stones analysed and I bet prevention is possible. Regards, Fred Coe
I am 70 years old and recently have had recurring UTI infections requiring 4 weeks of antibiotics. After a cat scan , it was discovered I have 6 mm kidney stones. I have made an appointment to see a urologist but where I live I have to wait a month for the first visit. I was able to have a telemedicine with a urology nurse practitioner and she told me I need surgery and advised me to sign papers for it. After reading your articles there is so much information I don’t have, type of stones etc. I am so confused. I can’t sign papers if I don’t what it entails. What questions can I ask the doctor when I see him? Should I follow the kidney stone diet? Does apple cider vinegar really dissolve the stones?
Fredric L Coe, MD
Hi Jackie, I would think that before surgery one might want to read a bit about how to think about an evaluation. Here is a good introduction. Also, why must be stones be removed? Are they causing obstruction, pain, bleeding, infection? Will you get a stone free kidney from the planned procedure? Regards, Fred Coe
Hi Dr. Coe:
I am 64 and have hip dexa at -2.4. My urine calcium is 304. I am a vegetarian, weigh 112 and exercise every day. I just realized that all the spinach, almond milk and almonds that I eat have been increasing my oxalates and I presume, lowering my calcium absorption. Should I completely stop consuming these? Also, there seems to be conflicting information as to whether to eat calcium with oxalates, which would reduce the calcium absorption or eating food with oxalates separately from food with calcium. If eaten together, should the dietary calcium be increased to compensate for the offset by the oxalates?
Thank you for all of the work that you do. It is so appreciated!
Fredric L Coe, MD
Hi Gail, I also read your second comment about having had a single kidney stone 34 years ago without known relapse of stones. I deleted that second comment. I suspect the prior stone arose from the high urine calcium – a genetic condition – and that has also contributed to your bone disease. Oxalate is without relevance, the problem is that given long term urine calcium losses bone mineral stones can wane unless diet calcium is high and diet sodium restrained. Food oxalate is not able to influence calcium absorption – apart from weird excesses – though diet calcium can lower oxalate absorption. The ideal is a 1200 mg calcium 1500 – 2000 mg sodium diet as an attempt to maintain bone stores, provided there is no other organic disease present. The one trial presented in the article is seemingly the only actual trial of this diet in post menopausals, but is very compelling. From your diet precis I see little calcium intake. Regards, Fred Coe