Diet for Kidney 

Stone Prevention

National Kidney and Urologic Diseases Information Clearinghouse

How does diet affect the risk 

of developing kidney stones?

Kidney stones can form when substances 

in the urine—such as calcium, oxalate, and 

phosphorus—become highly concentrated. 

The body uses food for energy and tissue 

repair. After the body uses what it needs, 

waste products in the bloodstream are 

carried to the kidneys and excreted as urine. 

Diet is one of several factors that can 

promote or inhibit kidney stone formation. 

Certain foods may promote stone formation 

in people who are susceptible, but scientists 

do not believe that eating any specific food 

causes stones to form in people who are 

not susceptible. Other factors that affect 

kidney stone formation include genes, 

environment, body weight, and fluid intake. 

More information about kidney stones 

can be found in the National Kidney 

and Urologic Diseases Information 

Clearinghouse fact sheets Kidney Stones 

in Adults and Kidney Stones in Children at 

www.kidney.niddk.nih.gov.

What are the types of kidney 

stones?

Four major types of kidney stones can form:

•	 Calcium stones are the most common 

type of kidney stone and occur in two 

major forms: calcium oxalate and 

calcium phosphate. Calcium oxalate 

stones are more common. Calcium 

oxalate stone formation may be caused 

by high calcium and high oxalate 

excretion. Calcium phosphate stones 

are caused by the combination of 

high urine calcium and alkaline urine, 

meaning the urine has a high pH.

•	 Uric acid stones form when the 

urine is persistently acidic. A diet 

rich in purines—substances found in 

animal protein such as meats, fish, 

and shellfish—may increase uric 

acid in urine. If uric acid becomes 

concentrated in the urine, it can settle 

and form a stone by itself or along with 

calcium.

•	 Struvite stones result from kidney 

infections. Eliminating infected stones 

from the urinary tract and staying 

infection-free can prevent more 

struvite stones. 

•	 Cystine stones result from a genetic 

disorder that causes cystine to leak 

through the kidneys and into the 

urine, forming crystals that tend to 

accumulate into stones.
 

Why is knowing which type 

of kidney stone a person has 

important? 

The first step in preventing kidney stones 

is to understand what is causing the stones 

to form. This information helps the health 

care provider suggest diet changes to 

prevent future kidney stones. For example, 

limiting oxalate in the diet may help prevent 

calcium oxalate stones but will do nothing 

to prevent uric acid stones. Some dietary 

recommendations may apply to more than 

one type of stone. Most notably, drinking 

enough fluids helps prevent all kinds of 

kidney stones by keeping urine diluted and 

flushing away materials that might form 

stones. 

How does a health care 

provider determine the type 

of kidney stone? 

If a person can catch a kidney stone as it 

passes, it can be sent to a lab for analysis. 

Stones that are causing symptoms can be 

retrieved surgically or with a scope inserted 

through the urethra into the bladder or 

ureter, then sent to a lab for analysis. 

Blood and urine can also be tested for 

unusual levels of chemicals such as calcium, 

oxalate, and sodium to help determine what 

type of kidney stone a person may have had. 

Dietary Changes to Help 

Prevent Kidney Stones 

People can help prevent kidney stones 

by making changes in fluid intake and, 

depending on the type of kidney stone, 

changes in consumption of sodium, 

animal protein, calcium, and oxalate. 

Drinking enough fluids each day is the 

best way to help prevent most types of 

kidney stones. Health care providers 

recommend that a person drink 2 to 

3 liters of fluid a day. People with 

cystine stones may need to drink even 

more. Though water is best, other 

fluids may also help prevent kidney 

stones, such as citrus drinks. 

Recommendations based on the 

specific type of kidney stone include the 

following: 

Calcium Oxalate Stones 

•	 reducing sodium 

•	 reducing animal protein, such as 

meat, eggs, and fish 

•	 getting enough calcium from food 

or taking calcium supplements with 

food 

•	 avoiding foods high in oxalate, 

such as spinach, rhubarb, nuts, and 

wheat bran 

Calcium Phosphate Stones 

•	 reducing sodium 

•	 reducing animal protein 

•	 getting enough calcium from food 

or taking calcium supplements with 

food 

Uric Acid Stones 

•	 limiting animal protein 

2 Diet for Kidney Stone Prevention 
 

How much fluid should a 

person drink to prevent 

kidney stone formation? 

People who have had a kidney stone should 

drink enough water and other fluids to 

produce at least 2 liters of urine a day. 

People who have had cystine stones may 

need to drink even more. The amount of 

fluid each person needs to drink depends 

on the weather and the person’s activity 

level—people who work or exercise in hot 

weather need more fluid to replace the fluid 

they lose through sweat. A 24-hour urine 

collection may be used to determine the 

volume of urine produced during a day. If 

the volume of urine produced is too low, 

the person can be advised to increase fluid 

intake. Drinking enough fluid is the most 

important thing a person can do to prevent 

kidney stones. 

Some studies suggest citrus drinks like 

lemonade and orange juice protect against 

kidney stones because they contain citrate, 

which stops crystals from growing into 

stones. 

How does sodium in the 

diet affect kidney stone 

formation? 

Sodium, often from salt, causes the kidneys 

to excrete more calcium into the urine. 

High concentrations of calcium in the urine 

combine with oxalate and phosphorus to 

form stones. Reducing sodium intake is 

preferred to reducing calcium intake. 

The U.S. recommended dietary allowance 

(RDA) of sodium is 2,300 milligrams (mg), 

but Americans’ intake averages 3,400 mg, 

according to the U.S. Department of 

Agriculture.1 The risk of kidney stones 

increases with increased daily sodium 

consumption. People who form calcium 

oxalate or calcium phosphate stones should 

limit their intake to the U.S. RDA level, 

even if they take medications to prevent 

kidney stones. 

1U.S. Department of Agriculture and U.S. Department 

of Health and Human Services. Dietary Guidelines 

for Americans, 2010. 7th ed. Washington, D.C.: U.S. 

Government Printing Office; December 2010. 

How can a person limit 

sodium intake? 

Learning the sodium content of foods can 

help people control their sodium intake. 

Food labels provide information about 

sodium and other nutrients. Keeping 

a sodium diary can help a person limit 

sodium intake to 2,300 mg. When eating 

out, people should ask about the sodium 

content of the foods they order. 

Some foods have such large amounts of 

sodium that a single serving provides a 

major portion of the RDA. Foods that 

contain high levels of sodium include 

•	 hot dogs 

•	 canned soups and vegetables 

•	 processed frozen foods 

•	 luncheon meats 

•	 fast food 

3 Diet for Kidney Stone Prevention 
 

People who are trying to limit their sodium 

intake should check labels for ingredients 

and hidden sodium, such as 

•	 monosodium glutamate, or MSG 

•	 sodium bicarbonate, the chemical 


name for baking soda
 

•	 baking powder, which contains sodium 

bicarbonate and other chemicals 

•	 disodium phosphate 

•	 sodium alginate 

•	 sodium nitrate or nitrite 

How does animal protein in 

the diet affect kidney stone 

formation? 

Meats and other animal protein—such as 

eggs and fish—contain purines, which break 

down into uric acid in the urine. Foods 

especially rich in purines include organ 

meats, such as liver. People who form 

uric acid stones should limit their meat 

consumption to 6 ounces each day. 

Animal protein may also raise the risk of 

calcium stones by increasing the excretion 

of calcium and reducing the excretion of 

citrate into the urine. Citrate prevents 

kidney stones, but the acid in animal 

protein reduces the citrate in urine. 

How does calcium in the 

diet affect kidney stone 

formation? 

Calcium from food does not increase the 

risk of calcium oxalate stones. Calcium in 

the digestive tract binds to oxalate from 

food and keeps it from entering the blood, 

and then the urinary tract, where it can 

form stones. People who form calcium 

oxalate stones should include 800 mg of 

calcium in their diet every day, not only 

for kidney stone prevention but also to 

maintain bone density. A cup of low-fat 

milk contains 300 mg of calcium. Other 

dairy products such as yogurt are also high 

in calcium. For people who have lactose 

intolerance and must avoid dairy products, 

orange juice fortified with calcium or 

dairy with reduced lactose content may be 

alternatives. Calcium supplements may 

increase the risk of calcium oxalate stones if 

they are not taken with food. 

How does oxalate in the 

diet affect kidney stone 

formation? 

Some of the oxalate in urine is made by 

the body. However, eating certain foods 

with high levels of oxalate can increase 

the amount of oxalate in the urine, where 

it combines with calcium to form calcium 

oxalate stones. Foods that have been 

shown to increase the amount of oxalate in 

urine include 

•	 spinach 

•	 rhubarb 

•	 nuts 

•	 wheat bran 

Avoiding these foods may help reduce the 

amount of oxalate in the urine. 

4 Diet for Kidney Stone Prevention 
 

 

What diet plan should a 

person follow to prevent 

future kidney stones? 

A dietitian can help a person plan meals 

that lower the risk of forming stones based 

on the type of stone the person formed in 

the past. A person with a history of kidney 

stones may want to talk to a dietitian who 

specializes in kidney stone prevention or 

nutrition for people with kidney problems. 

A dietitian can also help overweight people 

plan meals to help them lose weight. Studies 

have shown that being overweight increases 

the risk of kidney stones, particularly 

uric acid stones. Diets that are low in 

carbohydrates have been shown to further 

increase the risk of uric acid stones and 

should be avoided. 

Studies have shown the Dietary Approaches 

to Stop Hypertension (DASH) diet can 

reduce the risk of kidney stones. The 

DASH diet is high in fruits and vegetables, 

moderate in low-fat dairy products, and 

low in animal protein. More information 

about the DASH diet can be found on the 

National Heart, Lung, and Blood Institute’s 

website at www.nhlbi.nih.gov/health/ 

health-topics/topics/dash. 

Points to Remember 

•	 Kidney stones can form when 

substances in the urine—such as 

calcium, oxalate, and phosphorus— 

become highly concentrated. Diet is 

one of several factors that can promote 

or inhibit kidney stone formation. 

•	 Four major types of kidney stones can 

form: calcium stones, uric acid stones, 

struvite stones, and cystine stones. 

•	 Drinking enough fluid is the most 


important thing a person can do to 


prevent kidney stones.
 

•	 People who have had a kidney stone 

should drink enough water and other 

fluids to make at least 2 liters of urine 

a day. 

•	 Sodium, often from salt, causes the 

kidneys to excrete more calcium into 

the urine. High concentrations of 

calcium in the urine combine with 

oxalate and phosphorus to form 

stones. Reducing sodium intake is 

preferred to reducing calcium intake. 

•	 Meats and other animal protein—such 

as eggs and fish—contain purines, 

which break down into uric acid in the 

urine. 

•	 Calcium from food does not increase 

the risk of calcium oxalate stones. 

Calcium in the digestive tract binds to 

oxalate from food and keeps it from 

entering the blood, and then the 

urinary tract, where it can form stones. 

•	 A dietitian can help a person plan 

meals that lower the risk of forming 

stones based on the type of stone the 

person formed in the past. 

5 Diet for Kidney Stone Prevention 
 

Hope through Research 

The National Institute of Diabetes and 

Digestive and Kidney Diseases (NIDDK) 

funds research on the causes, treatments, 

and prevention of kidney stones. The 

International Registry for Hereditary 

Kidney Stone Diseases, funded under 

National Institutes of Health (NIH) clinical 

trial number NCT00588562, collects 

medical information from a large number 

of patients with kidney stones to create a 

registry that will help researchers compare 

similarities and differences in patients and 

their symptoms. 

The Study of the Biological and Physical 

Manifestations of Spontaneous Uric Acid 

Kidney Stone Disease, funded under NIH 

clinical trial number NCT00904046, aims 

to determine how much fat accumulates 

within cells and how it affects the kidneys 

by correlating kidney fat content with urine 

test results. A second aim is to evaluate the 

effect of the medication thiazolidinedione 

on excess fatty acid accumulation in kidney 

tissue and its correlation with uric acid 

stone formation. 

Tamsulosin for Urolithiasis in the 

Emergency Department, funded under NIH 

clinical trial number NCT00382265, studies 

the effectiveness and safety of tamsulosin in 

treatment of kidney stones. Other areas of 

focus include reduction in time to pain-free 

recovery, decrease in narcotic medication 

for pain, less need for follow-up, decrease 

in the need for surgery, and cost savings. 

Clinical trials are research studies involving 

people. Clinical trials look at safe and 

effective new ways to prevent, detect, or 

treat disease. Researchers also use clinical 

trials to look at other aspects of care, such 

as improving the quality of life for people 

with chronic illnesses. To learn more about 

clinical trials, why they matter, and how to 

participate, visit the NIH Clinical Research 

Trials and You website at www.nih.gov/ 

health/clinicaltrials. For information about 

current studies, visit www.ClinicalTrials.gov. 

6 Diet for Kidney Stone Prevention 
 

 

For More Information 

National Kidney Foundation 

30 East 33rd Street 

New York, NY 10016 

Phone: 1–800–622–9010 or 212–889–2210 

Fax: 212–689–9261 

Internet: www.kidney.org 

Oxalosis and Hyperoxaluria Foundation 

201 East 19th Street, Suite 12E 

New York, NY 10003 

Phone: 1–800–OHF–8699 

(1–800–643–8699) or 212–777–0470 

Fax: 212–777–0471 

Email: kimh@ohf.org 

Internet: www.ohf.org 

Urology Care Foundation 

1000 Corporate Boulevard 

Linthicum, MD 21090 

Phone: 1–800–828–7866 or 410–689–3700 

Fax: 410–689–3998 

Email: info@urologycarefoundation.org 

Internet: www.UrologyHealth.org 

Acknowledgments 

Publications produced by the 

Clearinghouse are carefully reviewed by 

both NIDDK scientists and outside experts. 

The original version of this fact sheet was 

reviewed by Gary Curhan, M.D., Harvard 

Medical School, and David Goldfarb, M.D., 

New York University School of Medicine. 

You may also find additional information about this 

topic by visiting MedlinePlus at www.medlineplus.gov. 

This publication may contain information about 

medications. When prepared, this publication 

included the most current information available. 

For updates or for questions about any medications, 

contact the U.S. Food and Drug Administration tollfree at 1–888–INFO–FDA (1–888–463–6332) or visit 

www.fda.gov. Consult your health care provider for 

more information. 

7 Diet for Kidney Stone Prevention 
National Kidney and 

Urologic Diseases 

Information Clearinghouse

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Phone: 1–800–891–5390

TTY: 1–866–569–1162

Fax: 703–738–4929

Email: nkudic@info.niddk.nih.gov

Internet: www.kidney.niddk.nih.gov 

The National Kidney and Urologic 

Diseases Information Clearinghouse 

(NKUDIC) is a service of the National 

Institute of Diabetes and Digestive and 

Kidney Diseases (NIDDK). The NIDDK 

is part of the National Institutes of Health 

of the U.S. Department of Health and 

Human Services. Established in 1987, 

the Clearinghouse provides information 

about diseases of the kidneys and urologic 

system to people with kidney and urologic 

disorders and to their families, health 

care professionals, and the public. The 

NKUDIC answers inquiries, develops and 

distributes publications, and works closely 

with professional and patient organizations 

and Government agencies to coordinate 

resources about kidney and urologic 

diseases.

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encourages users of this publication to duplicate and 

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This publication is available at 

www.kidney.niddk.nih.gov.

NIH Publication No.13–6425

February 2013

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