If you’ve had a kidney stone, you already know how painful they can be.
If you haven’t had a kidney stone, you probably want to keep it that way.
Certain foods can cause kidney stones, and other lifestyle tips can help minimize your risk of developing one.
What are kidney stones?
Kidney stones are hard deposits of minerals and salts that form in your kidneys.
Kidney stones 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 start to 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. (1)
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.
What are the signs and symptoms of kidney stones?
Some of the symptoms of kidney stones may include:
- Severe, sharp pain in your side and back, below your ribs
- Pain that radiates to your lower abdomen and groin
- Pain that comes in waves and fluctuates in intensity
- Burning sensation or pain 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
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.
Types of kidney stones
Once a kidney stone is passed, it can be analyzed to determine what it is comprised of. There are four main types of kidney stones:
Most kidney stones are made of calcium oxalate. Oxalate is a substance your liver produces, but some foods are high in oxalates.
Calcium phosphate stones are another type of calcium stone but aren’t as common as calcium oxalate stones. Calcium phosphate stones can be associated with certain medications to treat migraines or seizures.
Even though calcium is in the name, calcium-rich foods don’t cause calcium oxalate stones. Calcium helps bind to oxalates and can prevent kidney stones. People with the lowest calcium intake tend to have more kidney stones.
Struvite stones can form when you have a urinary tract infection due to changes in the urine from the bacteria. These stones grow quickly and can become quite large and come on with little warning.
Uric acid stones
Uric acid is a waste product in your blood. High uric acid levels can form crystals in your urine and cause kidney stones.
You may be at higher risk of developing a uric acid kidney stone if you have gout. Gout is a condition where you have high levels of uric acid in your blood which can form painful crystals in your joints.
These stones are rare and form in people with a hereditary disorder called cystinuria. Cystinuria is a condition where too much cystine (a type of amino acid) is leaked into your urine. People with cystinuria tend to have recurring kidney stones.
What are the risk factors for developing kidney stones?
Several risk factors can increase the likelihood of you developing kidney stones.
Family or personal history
If you’ve had a kidney stone in the past, you’re at higher risk of developing another one in the future. Having a family history of kidney stones, even if you haven’t had one yet, is a risk factor as well.
If you don’t drink enough water and/or you live in hot climates where you lose a lot of sweat, your kidney stone risk is higher.
High-sodium diets are linked with kidney stones. Most people eat too much sodium compared to the recommended amount, so this is a more common risk factor.
Digestive diseases and some types of digestive surgery
Gastric bypass surgery, inflammatory bowel disease, and chronic diarrhea can cause alter the balance of water and certain minerals in your urine, which may increase your kidney stone risk.
Medical conditions like renal tubular acidosis, cystinuria, hyperparathyroidism (a condition that causes high blood calcium levels), and repeated urinary tract infections (which cause struvite stones) are all risk factors.
Certain supplements and medications
Some supplements and medications such as vitamin C, excessive use of laxatives, calcium-based antacids, and certain medications used to treat migraines or depression can increase your risk of kidney stones.
Foods that can cause kidney stones
Foods that cause kidney stones will depend on the type of kidney stone you have a history of developing. Having your kidney stone tested after it’s passed can help you identify which foods you might need to avoid in the future.
1. High oxalate foods
Calcium oxalate stones are the most common type of kidney stone. Some high-oxalate foods you may need to limit to prevent kidney stones include:
- Soy products (tofu, tempeh, edamame, soy milk, etc.)
- Navy beans
If you eat high-oxalate foods, be sure to drink plenty of water to help your body flush the oxalates out through your urine. Eating high-calcium foods to help bind to the oxalates and remove them from your body can also help.
Avoid high doses of vitamin C if you’re prone to calcium oxalate stones, which can increase oxalic acid production in your body.
Cooking high-oxalate vegetables can lower their oxalate content.
If you’re looking for low-oxalate alternatives to the foods in the above list, consider:
- Kale or bok choy instead of spinach
- Cashews, peanuts, or walnuts instead of almonds
- Pumpkin and sunflower seeds
- Sweet potatoes instead of white potatoes
- Kidney beans instead of navy beans
- Blueberries or blackberries instead of raspberries
- Dried figs instead of dates
2. High-sodium foods
A high-sodium diet can increase the amount of calcium in your urine, which can cause kidney stones. The recommended daily limit for sodium is less than 2,300 milligrams per day. If you have a history of kidney stones, you might want to consider limiting your sodium intake even further.
Sodium is found in table salt, but table salt isn’t the main source of sodium in most people’s diets. Processed foods are the leading culprit for sodium.
Some examples of high-sodium foods include:
- Smoked, cured, or canned meats, such as 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
If you have a history of stones made of uric acid, you may need to limit (or at least eat in moderation) high-purine foods. Purines are a chemical compound in some foods that increase levels of uric acid in your body.
Some high-purine foods include:
- Organ meats like liver and kidney
- Red meat
- Sweetened drinks and sugary foods
4. Excessive vitamin C intake
Consuming large amounts of vitamin C can increase the calcium level in your urine and may lead to kidney stones. It’s more likely that you’d over-do vitamin C in the form of supplements and not food, but you should still be aware of foods high in vitamin C like:
- Acerola cherries
- Chili peppers
- Sweet bell peppers
- Brussels sprouts
- Citrus fruit like oranges and grapefruit
Other ways to prevent kidney stones
Some of the best ways to prevent kidney stones are:
Drinking plenty of fluids
If you’re dehydrated, your body can’t dissolve the salts and other compounds that can form hard crystals in your urine and lead to kidney stones.
Avoid spending a lot of time in saunas which cause you to lose a lot of sweat, therefore reducing the amount you may urinate.
You should be drinking enough fluids so that your urine is light in color. If it’s dark or has an odor, you’re likely not drinking enough, which increases your kidney stone risk.
RELATED: 10 Ways to Prevent Dehydration.
Eating enough calcium
Calcium helps bind to oxalates and removes them from your body, which reduces your risk of developing calcium oxalate stones. If you pair high-calcium foods with high-oxalate foods, you can reduce your kidney stone risk.
Some examples of high-calcium foods include:
- Seeds (chia seeds, poppy seeds, etc.)
- Cheese & other dairy products
- Sardines & canned salmon (calcium from the small edible bones)
- Beans & lentils
- Leafy green vegetables
Foods that cause kidney stones depend on the type of kidney stone that tends to form and can include high-oxalate and high-purine foods. Regardless of the type of kidney stone, you should drink plenty of fluids, avoid eating excessive sodium and avoid mega doses of vitamin C to prevent kidney stones.