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What is the best diet for kidney stone prevention?

I just had a kidney stone and really don’t want to have another one. I looked online and there are conflicting things about what I should eat to prevent a recurrence. What is the best diet?

vetstud / Originally posted on Oxalates in cinnamon

Answer:

I’m going to assume you have what’s called idiopathic calcium nephrolithiasis (but if you can actually catch a stone and have it analyzed, your physician can make more specific recommendations). ICN–the formation of calcium oxalate stones (sometimes mixed with calcium phosphate)–accounts for about 80% of cases (though you should see your physician to rule out a variety of hereditary and acquired diseases that can cause those in the 20%).

The most important thing folks with ICN can do is drink lots of water, at least 2 liters a day, to dilute the concentration of calcium, oxalate, and uric acid in your urine to decrease the likelihood of stone formation and flush away seeding crystals. Water’s probably the best, but if you are going to drink other liquids, OJ is preferable to grapefruit juice, apple juice, and tea.

In terms of food, according to the latest review on the subject, the most important thing is to reduce meat consumption (vegetarians may have only half the kidney stone risk). The reasons given why animal proteins are bad is because of hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, and the acidification of the urine. You should also cut down on salt, and the more fruits and vegetables the better–they tend to have a high water, potassium, and magnesium content; a low sodium chloride content; and a high urine alkalinization power because of the presence of bicarbonate and citrate. I would warn against megadosing with vitamin C (as you’ll see across the internet) as this may exacerbate stone formation.

How else can we keep our kidneys healthy? See my videos Preventing Kidney Failure Through Diet and Treating Kidney Failure Through Diet (both summarized in my blog post Preventing and Treating Kidney Failure With Diet).

Image Credit: SweetOnVeg / Flickr

Dr. Michael Greger

About Michael Greger M.D.

Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

View all videos by Michael Greger M.D.

  • Jane Sirignano

    Hello Dr. Greger,

    I have attendees at cooking classes that have kidney stones from uric acid. They are told not to eat foods high in purines and also beans and greens with oxalates and yet they can still eat animal products.
    What do you recommend?
    Thanks for your help and inspiration.

  • Ede Steiger

    I have a six year old niece who has hereditary calcium kidney stones. She was told not to eat strawberries or spinach. No mention of fat or meat. Is this the correct solution?

    • Toxins

      Strawberries and spinach are indeed high oxalate foods so someone who has severe kidney issues should be cautious of these foods as well as other high oxalate foods such as chocolate. I would think that reducing overall animal product intake would help create a positive calcium balance as a higher protein, high sodium diet can cause excess excreted calcium.

      Calcium needs for humans are not as high as the DRI may recommend, and if we consumed a low sodium diet low in animal protein, our calcium needs can be as low as 450 mg per day as discussed more extensively in this article from the Food and Agriculture Organization of the UN. As represented in the figure below, and citing from the article “In a western-style diet, absorbed calcium matches urinary and skin calcium at an intake of 840 mg as in Figure 14. Reducing animal protein intakes by 40 g reduces the intercept [calcium balance] value and requirement to 600 mg. Reducing both sodium and protein reduces the intercept value to 450 mg.”

      http://www.fao.org/docrep/004/Y2809E/y2809e0h.htm#bm17

      • Mindy

        According to the Trying Low Oxalates group, 1/2 cup of strawberries are considered low ox. This group has the most current, comprehensive list of foods and their oxalates. It’s free to join and well worth it to get the lsit of over 1600 foods.
        http://groups.yahoo.com/neo/groups/Trying_Low_Oxalates/info

  • John Kerher

    This is interesting to me. I have had kidney stones since I was about 10 I think. I did not know that’s what it was till I was 18, I had only had a couple when I was younger than that and we thought that it was just bad gas. Doctors did not check to see that there was any blood in my urine before I was 18.

    Now that I am nearly 40, I have passed more than 40 kidney stones. I actually stopped counting after 30. I have a medicine jar with some in it just to shake and look at, and yes, they continue to grow in that jar. Most recently I found that I had some very large ones back in 2011 and in march of that year I had lithotripsy (blasted them) to get rid of the larger ones. As far as I know I am stone free now for 2 years. I have switched to a vegetarian (aspiring vegan) diet and have not had more.

    Its important to note that prior to that I had eaten a lot of meat. Loved eating jerky products. Lots of bbq, as well as lots of cheese products. getting to the point… I think that high protein in your diet causes kidney stones. Why, well I thought that I had read or heard that excess protein in your body cannot be absorbed. I don’t know all the science behind it but what I did understand was what I read or heard that followed. Excess protein has to exit your body through your urine, and also needs calcium to do so. I thought… what? Calcium? But that is what the stones are made of… there has to be a link there that is not being directly drawn.

    Well, its been 2 years now and I have not had a kidney stone. Usually I have at least one every year. To me, that is proof that what the doctors told me was not spot on and that they don’t understand the problem well enough yet.

    Something else that concerns me… protein is being put in everything, people are being duped into thinking that they need more protein. When I tell people that I am a vegetarian (and try not to eat dairy as well) the first thing I am asked is how I will get enough protein. I think that its simply a crime and is going to cause more problem and more people to experience the pain I have been having for nearly 30 years. Stay away from excess protein! I doubt that the average Joe needs to drink a protein shake. If your a body builder and your using it, that’s different!

    I also think that its important to note that I was told all sorts of things over the years to help prevent stones. Drink lots of water, don’t drink caffeine, don’t drink milk, eat less dairy. But no one ever told me to eat less protein, NO ONE, I had to figure that out for myself. I know that 2 years is not a lot of time, but its twice as long as I have gone without a stone since the age of 18.

    I would like to know if there has been a study on this, I think that it would be a good one.

  • Mary

    There is so much conflicting information about what you can/cannot eat if you are dealing with kidney stones. I consistently test deficient for Vitamin D, but some articles indicate that Vitamin D contributes to stone formation (in the diet, as well as too much sun). I am now also worried about eating kale and spinach. It would be helpful to know once and for all what “fruits and vegetables” are “harmless” to consume when kidney stones are a concern. It seems like spinach and kale would have to be avoided, along with beets and perhaps many other plant-based foods. As a gluten-free vegan, I am running out of things to eat. Help!

  • Buğra

    Dear Dr. Greger,

    I passed two kidney stones since I became a vegan about a year ago. The second one, which I know was a calcium oxalate stone, came about 4.5 months ago. I’d been drinking 200 ml of Ca-fortified soy milk every morning prior to that second incident, which I stopped immediately afterwards, assuming that that was the cause of my problem. However, I have reason to suspect more stones may be on the way now (although I think it may just be a case of stones loosening up now that were already there 4.5 months ago).

    In any event, after reading the info at http://www.busy-vegan.com/Calcium-Oxalate-Kidney-Stones.html, I became somewhat confused about what constitutes a balanced Ca diet for vegans like myself who are prone to kidney stones. (Please let me know if there’s anything on this website you strongly disagree with.) The website makes a distinction between digestible and indigestible Ca. But I can’t decide what’s good for me because I don’t know which foods and supplements contain digestible Ca and which foods and supplements contain indigestible Ca. Moreover, some of the foods listed as Ca-rich foods on the internet appear to also be rich in oxalate, which I’m supposed to be avoiding!

    Solgar has calcium citrate tablets that contain 250 mg Ca per tablet. The strategy I have in mind right now is to take one of these tablets with any meal that I fear may contain too much oxalate, never (or at least rarely) exceeding one tablet per day. Is that a sensible plan? Of course, it’s difficult for me to know (a) how much oxalate I’m consuming, and (b) how much is too much. So, to be on the safe side, should I just take one of these Solgar tablets every day for the rest of my life or would you say that even 250 mg of calcium citrate per day might be too much (or simply unnecessary)?

    Last but not least, I’d appreciate it if you would point me to reliable online info on the Ca and oxalate contents of various foods.

  • ARun Kumar

    It would be worthy if i mention the ideas of Hippocrates here.
    1. Before 2000+ years itself he has mentioned that water is the best medicine for stones.
    2. According to him “food is the medicine”. It is 100% true that instead of taking tablets/medicines, one must prefer to take healthy foods which cure the disease.

    For any health issue, optimizing diet is the best remedy.

    From
    Arun Kumar

    Visit us at http://www.passthekidneystone.com

  • Nik Hassan Salleh

    traditionally, water-melon does more than preventing formation of kidney stones. after being sliced into 2 and left overnight in the open, it helps to break up gall bladder stones. of course, it has to be consumed daily for at least 2 weeks…

  • mark

    I need a list of foods that I can eat an abundance of without getting kidney stones.

    • http://www.DonForresterMD.com/ Don Forrester MD

      As mentioned in Dr. Greger’s post above it depends on the type of stone(s) you have or are trying to prevent. The best advice is to start with plant based diet and 2 liters or 2 quarts of water intake per day. Beyond that as many of the above posts point out there are specific foods that can be considered to avoid depending on the type of stone.

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