What to Eat to Prevent Kidney Stones

Passing a kidney stone is excruciating! Here are some tips to reduce the chances that you'll ever have to endure that pain or relive past misery.

Monica Reinagel, MS, LD/N, CNS
4-minute read
Episode #546

As anyone who has ever had one can attest, passing a kidney stone is something you’re not likely to forget ... or remember fondly. Although dietary measures are not 100% effective in preventing stones, they can definitely reduce your risk.

What causes kidney stones?

Kidney stones can form when compounds that are normally found in urine form crystals and start to clump together. They may be as small as a grain of sand or as large as a small pebble. Small stones may pass out of the body without you noticing. If larger stones start to migrate through the urinary tract, you’re going to notice!

Although the pain of passing a kidney stone can be excruciating, they usually pass without causing any further damage. In rare cases, surgery or other treatment may be required. But in most cases, the only treatment is medication to alleviate the pain while they are on the move.

Who gets kidney stones?

About 1 in 10 people will experience a kidney stone at some point during their lifetime, and men are about twice as likely as women. Kidney stones generally occur after age 30, although it’s possible for a younger person to have one as well. Once you’ve had a kidney stone, you’re at a significantly higher risk for future stones.

About 1 in 10 people will experience a kidney stone at some point during their lifetime, and men are about twice as likely as women.

The tendency to form kidney stones tends to run in families, so if your parents or siblings have had stones, you may be at increased risk. Whether or not you have a family history of stones, though, certain dietary habits can increase or reduce your risk.

How to prevent kidney stones

Drink lots of water. The most important thing to do to prevent kidney stones is to drink plenty of water, which helps flush compounds out of the kidneys before they can start making trouble.

Reduce salt. Excessive sodium intake can also concentrate the urine, making stone formation more likely.

Eat your veggies. A diet high in fruits and vegetables, which raises the pH of the urine, can help prevent kidney stones.

High protein diets, which lower the pH of your urine, can make kidney stones more likely.

Keep protein intake moderate. High protein diets, which lower the pH of your urine, can make kidney stones more likely. If you are nervous about kidney stones, you’ll probably want to stick to a moderate protein diet and get at least some of your protein from plants. 

Get enough calcium. A low calcium diet can also be a risk factor. This fact surprises a lot of people because kidney stones often contain a lot of calcium, which seems to suggest that too much calcium would be to blame. But it’s actually the opposite. When your diet is higher in calcium, less of it is absorbed in the digestive tract and less ends up in the urine. The best way to get calcium is by eating a variety of calcium-containing foods (such as dairy products, leafy greens, tofu, canned fish) throughout the day. Taking your entire dietary allowance of calcium at one time in the form of a supplement, on the other hand, may slightly increase your risk of stones.

See also: Best sources of calcium

Calcium versus uric acid stones

Calcium-oxalate stones are by far the most common type, accounting for up to 80% of kidney stones. Uric acid stones are the next most common type. Drinking more fluids, reducing sodium, and avoiding excessive protein can help with either type. But there are some other specific recommendations that depend on which type of stone you tend to form.

If you’re unlucky enough to pass a stone, your doctor can analyze its composition. Even if there’s no stone to analyze, blood and urine tests can help identify the specific cause or composition of the stone, which can help focus your prevention efforts in the right direction.

Calcium stones. As I said before, having calcium-based stones does not mean you need to avoid calcium-rich foods. But if you have a calcium oxalate stone, you definitely want to avoid foods that are high in dietary oxalates. These include spinach, rhubarb, wheat bran, and nuts (including peanuts). That last one is a drag, of course, because, besides being delicious, nuts are a good source of healthy fats. But here’s a tip: Pistachios and chestnuts have the lowest oxalate levels, so if you wanted to indulge in a small serving of nuts once in a while, those would be the best choices.

Uric acid stones. If, on the other hand, you suffer from uric acid stones, it’s even more important for you to avoid excessive animal protein. In particular, foods that are rich in purine, which include shellfish and organ meats, can encourage the formation of uric acid stones. Fortunately, if uric acid is the culprit, you don’t need to be as worried about oxalates, which means that you can enjoy peanuts and other plant-based sources of protein. Diets containing dairy and eggs (but not meat) have also found to reduce uric acid crystalization

Weight loss and kidney stones

If you’re carrying some extra weight, losing a few pounds can also help reduce your risk. But I urge you to lose weight slowly. Fast weight loss—especially from low carb diets—may increase increase kidney stone risk.

If you’re carrying some extra weight, losing a few pounds can also help reduce your risk.

Instead of the 1-2 pounds a week (or more) that most popular diet programs encourage, we recommend that you aim to lose just a couple of pounds a month. Sure, it’ll take you a bit longer. But you’re likely to lose more body fat and less lean muscle that way. More importantly, you’ll have a much better chance at keeping it off long term, which is all that really matters.

See also: The case for super slow weight loss

Additional resources:

National Kidney Foundation

National Institute of Diabetes, Digestive, and Kidney Diseases


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About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.