Getting a kidney stone is usually a painful experience and one that you don’t want to endure again.
It’s estimated that one in ten people will get a kidney stone in their lifetime.
While you can’t control all of the factors that can cause a kidney stone, one major aspect you can control is your diet.
What is a kidney stone?
Kidney stones are hard deposits of minerals and salts that form in your kidneys. They can form in any part of your urinary tract, including your kidneys, ureter (the tube that connects your kidney to your bladder), and bladder.
You’ll likely experience symptoms once a kidney stone is large enough to move around in your kidney or if the kidney stone becomes lodged in your ureter.
Kidney stone symptoms typically resolve once the stone is passed. Kidney stones don’t usually cause permanent damage if they are identified and treated if needed.
However, if you have a large stone that becomes stuck in your urinary tract, it can disrupt the flow of urine from your kidney to your bladder and cause intense pain and swelling. Large stones may require surgical intervention to prevent scarring and permanent damage to your kidneys.
Kidney stones typically affect people 30 years and older, but children can also get them. It’s estimated that 19% of men and 9% of women will develop a kidney stone in their lifetime.
Some of the symptoms of kidney stones may include:
- Pain that radiates to your lower abdomen and groin
- Severe, sharp pain in your side and back, below your ribs
- Pain that comes in waves and fluctuates in intensity
- Pain or burning sensation while urinating
Other signs and symptoms of kidney stones may include:
- Pink, red, or brown urine
- Cloudy or foul-smelling urine
- A persistent need to urinate, urinating more often than usual, or urinating in small amounts
- Nausea and vomiting
- Fever and chills if an infection is present
There are different types of kidney stones. You can find out what your kidney stone is made of once you pass it by having it analyzed.
Calcium oxalate stones are the most common type of kidney stone. The other types of kidney stones include:
- Struvite stones
- Uric acid stones
- Cystine stones
What is a kidney stone diet?
Your diet can impact your kidney stone risk. A kidney stone diet helps reduce your likelihood of developing a kidney stone by limiting certain foods that are more likely to promote a kidney stone (1).
If you’re prone to kidney stones, you’ll need to avoid foods that increase the likelihood of your particular type of kidney stone. For instance, if you get uric acid stones, you shouldn’t eat a very purine-rich diet, which increases uric acid levels in your body.
Foods to avoid to prevent kidney stones
1) High oxalate foods
Calcium oxalate stones are the most common type of kidney stone and form when you have too much oxalate in your urine. Eating high-oxalate foods can increase the amount of oxalate in your urine, so you may need to avoid eating large amounts of high-oxalate foods like:
- Soy products (tofu, tempeh, edamame, soy milk, etc.)
- Nuts and nut butter
- Bran flakes
2) High sodium foods
A high-sodium diet can increase the amount of calcium excreted in your urine, which can cause kidney stones. The recommended daily limit for sodium is fewer than 2,300 milligrams per day, yet the average sodium intake for American adults is around 3,400 milligrams.
Sodium is found in table salt, which most people think of when they hear that they should limit sodium. However, table salt isn’t the main source of sodium in most people’s diets. Instead, processed and convenience foods are the leading culprit for sodium.
Some examples of high-sodium foods include:
- Smoked, cured, or canned meats, including bacon, deli meat, sausage, sardines, anchovies, etc.
- Frozen dinners like burritos, pizzas, and other “TV dinners.”
- Canned meals like chili, soups, “Spaghetti-O’s”, etc.
- Canned beans and vegetables with salt added.
- Salty snacks like chips, microwave popcorn, pretzels, etc.
3) High purine foods
Purines are a type of chemical compound found in certain foods. Kidney stones made of uric acid can arise from eating too many purines in your diet because purines are converted to uric acid in your body.
Some high-purine foods you may need to avoid for uric acid kidney stones include:
- Some fish, seafood, and shellfish, such as anchovies, sardines, herring, mussels, codfish, scallops, trout, and haddock
- Red meat, processed meats like bacon, turkey
- Game meats like goose, veal, and venison
- Gravy and meat sauces
- Yeast and yeast extract
- Glandular and organ meats like kidney, liver, tripe, and others are especially high in purines and should be avoided if you suffer from gout.
Foods to eat to prevent kidney stones
Eating a healthy diet rich in whole foods and low in sodium can help prevent kidney stones.
If you’re prone to a specific type of kidney stone that requires limiting any of the foods below, then disregard that food.
1) High calcium foods
It might seem counterintuitive to eat calcium foods since most kidney stones are made of calcium oxalate. However, eating calcium helps bind to oxalates and removes them from your body, which reduces your risk of developing calcium oxalate stones.
People with the lowest calcium intake are more likely to have kidney stones. You can reduce your kidney stone risk by eating calcium-rich foods when you eat high-oxalate foods.
Aim to get 1,200 milligrams of calcium daily, and avoid calcium supplements if you’re also eating calcium-rich foods.
Some good sources of calcium include:
- Dairy products, including milk, cheese, and yogurt
- Seeds (chia seeds, poppy seeds, etc.)
- Sardines & canned salmon (calcium comes from the small edible bones)
- Beans & lentils
- Leafy green vegetables
- Foods fortified with calcium
2) Moderate amounts of lean protein
Very high-protein diets can cause higher levels of calcium in your body and lead to calcium-based kidney stones. On a kidney stone diet, aim to eat moderate amounts of high-quality protein (avoiding those very high in purines if you’re prone to uric acid stones).
Some examples of lean protein include chicken, turkey, fish, lean cuts of red meat, pork tenderloin, eggs, and low-fat dairy.
3) Fruits and vegetables
Eating fruits and vegetables helps contribute beneficial vitamins and nutrients to your diet. Many fruits and vegetables are allowed on a kidney stone diet, except for high-oxalate varieties if you need to limit oxalates.
Some low-oxalate vegetables include:
- Romaine lettuce
- Bok choy
- Water chestnuts
Most fruits are low enough in oxalates that you don’t have to worry about it on a kidney stone diet. Raspberries are higher in oxalates with 48 milligrams per cup, but compare that to cooked spinach (755 milligrams in a half-cup) for comparison.
4) Low-sodium foods
Eating unprocessed foods is the best way to limit sodium in your diet since a high-sodium diet can increase your risk of kidney stones.
Here are some examples of lower-sodium choices:
Fruits & vegetables:
- Any fresh or frozen fruit; canned or dried fruit without added sugar
- Any fresh or frozen vegetables (without any added sauce)
- Canned vegetables that are low in sodium or have no salt added; rinse low-sodium veggies to lower the sodium content
- Low-sodium vegetable juice
- Frozen, canned, or dried fruits with no added sugars
- Whole grains like brown or wild rice, quinoa, or barley
- Whole-wheat or whole-grain pasta and couscous (no salt added while cooking)
- Unsalted popcorn; low-sodium chips, and pretzels
- Whole-grain hot or cold breakfast cereals with no added sugar like plain oats
- Whole-grain bread, bagels, English muffins, etc. with fewer than 140 milligrams of sodium per serving
- Fresh or frozen fish or shellfish
- Skinless chicken or turkey breast (no high-sodium marinades)
- Lean cuts of beef or pork
- Unsalted nuts and seeds
- Dried beans, peas, and lentils
- Canned beans labeled “no salt added” or “low sodium”; rinse to remove excess sodium
- Fat-free or low-fat (1%) milk
- Fat-free or low-fat plain yogurt
- Low-sodium or reduced-sodium cheese; or watch your portion size of regular cheese
- Soy milk or soy yogurt
- Unsalted butter or vegetable oil spreads
- Vegetable oils
- Low-sodium salad dressing
- Oil & vinegar
- Low-sodium or “no salt added” ketchup
- Low-sodium salsa; pico de gallo
- Herbs, spices, or salt-free seasoning blends
- Lemon and lime juice
5) Healthy fats
There isn’t a correlation between fat intake and kidney stones. Whenever possible, choose healthy unsaturated fats, which are beneficial for your heart health and may even help reduce inflammation.
Examples of healthy fats include vegetable oils (especially those high in omega-3s like flaxseed oil and canola oil), fatty fish like salmon, avocados, nuts, and seeds.
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Tips for a kidney stone diet
- Find out what kind of kidney stones you’ve had before. If you’ve had kidney stones before, you’re probably following a kidney stone diet. To best tailor your diet for kidney stone prevention, you should find out what kind of kidney stones you had. This way, you’re not avoiding foods you don’t necessarily need to be, and you’ll have a better chance of success in preventing future kidney stones.
- Instead of worrying about cutting out oxalate-rich foods from your diet completely, remember that eating calcium-rich foods along with oxalates can help reduce your kidney stone risk (calcium helps bind to oxalates in your stomach before they reach your kidneys). An inadequate amount of calcium in your diet is a risk factor for developing kidney stones.
Can diet alone prevent kidney stones?
While making diet changes can help prevent kidney stones, it might not be enough to completely prevent them.
You may be more at risk of getting kidney stones based on other factors, including:
- Having a personal or family history of kidney stones.
- Having certain digestive diseases or digestive surgeries, including some types of gastric bypass surgery.
- Taking certain medications (calcium-based antacids, high doses of vitamin C, certain prescription medications). Ask your healthcare provider or pharmacist if any of your medications increase your kidney stone risk.
Other ways to prevent kidney stones
Avoid excessive vitamin C intake
Taking megadoses of vitamin C, such as the amount in some immune support supplements, can increase your risk of kidney stones. It’s fine to eat vitamin C in whole foods or take it in small amounts as a supplement, but avoid consuming over 1,000 milligrams daily.
Drinking enough fluids can help dilute the salts and other compounds that form to make kidney stones. You’re more likely to suffer from a kidney stone if you’re dehydrated.
Diet plays a significant role in kidney stone formation, especially if you have other risk factors that predispose you to kidney stones.
Eating a high-sodium diet and/or high-oxalate diet, not eating enough calcium, and not drinking enough water can increase your risk of getting kidney stones.
To help reduce your risk of kidney stones, focus on reducing your salt intake, be mindful of how many oxalates you eat, eat enough calcium (especially if you’re eating oxalate-rich foods), and stay hydrated, and avoid megadoses of vitamin C.