Kidney Stones Diet and Prevention

Kidney stones are small, hard pieces of material that can form in your kidneys. They are made from substances in your urine (pee). A stone may stay in the kidney or move through the urinary tract, which includes the kidneys, ureters, bladder, and urethra.

Urine contains minerals, salts, and other substances. When there is too much of certain substances and not enough fluid, crystals can form. Over time, these crystals can grow into a kidney stone.

Diet and nutrition can play an important role in kidney stone prevention. There is no single diet plan that is right for everyone with kidney stones. The best plan depends on the type of stone you have, your urine and blood test results, your medicines, and your overall health.

A doctor, registered dietitian, or registered kidney dietitian can help you understand which changes are right for you.

Kidney stones are more likely to form when urine has too little fluid and too much of certain minerals, salts, or acids. Diet and lifestyle habits can affect this balance.

Things that may raise the risk of kidney stones include:

• Not drinking enough fluids
• Sweating a lot from heat, exercise, saunas, or hot yoga without replacing fluids
• Eating a lot of sodium. Sodium is found in salt, packaged foods, fast foods, restaurant meals, and many condiments.
• Eating large amounts of animal protein, such as beef, pork, poultry, fish, shellfish, and eggs
• Eating foods high in oxalate if you form calcium oxalate stones. Oxalate is a natural substance found in some foods.
• Taking some vitamins or mineral supplements without talking with your care team

Other health issues can also raise the risk of kidney stones. These may include gout, urinary tract problems, bowel disease, obesity, some inherited conditions, and a personal or family history of kidney stones.

There is no single diet plan that prevents kidney stones for everyone. The best plan depends on the type of stone you have, your urine test results, your health history, and your medicines.

Your doctor may test your kidney stone, blood, or urine. These tests can help your care team know what changes may help prevent another stone.

For calcium oxalate stones

Calcium oxalate stones are the most common type of kidney stone. They are one type of calcium kidney stone.

Oxalate is a natural substance found in many foods. You may not need to avoid all foods with oxalate. Your doctor or dietitian can help you know which foods, if any, you should limit.

Some foods that are high in oxalate include:

• Spinach
• Rhubarb
• Beets
• Swiss chard
• Sweet potatoes
• Peanuts
• Chocolate
• Tea

If you form calcium oxalate stones, your doctor or dietitian may tell you to limit some foods that are high in oxalate. Your plan should be based on your own test results.

Do not stop eating calcium foods unless your doctor tells you to. Calcium is important for your bones and your overall health. Eating too little calcium can actually raise your risk for calcium oxalate stones.

A helpful tip is to eat calcium-rich foods with meals that include oxalate foods. Calcium and oxalate can connect in your stomach and intestines before they reach your kidneys. This may help lower the chance that stones will form.

Calcium-rich foods include:

• Milk
• Yogurt
• Cheese
• Calcium-fortified foods, if recommended by your care team

Many adults need about 1,000 to 1,200 milligrams, or mg, of calcium each day from food. Your doctor or dietitian can help you know how much calcium is right for you.

Sodium can raise your risk for stones

Sodium is found in salt. Eating too much sodium can cause more calcium to leave your body through your urine. This can raise your chance of forming another stone.

Try to limit high-sodium foods, such as:

• Fast food
• Restaurant meals
• Canned soups
• Packaged meals
• Deli meats
• Chips and salty snacks
• Frozen meals
• Foods with a lot of added salt

Choosing more fresh foods and lower-sodium options can help lower your stone risk. It can also help manage blood pressure.

For uric acid stones

Uric acid stones can form when there is too much uric acid in the urine. Some foods can raise uric acid levels. These foods are often high in purines. Purines are natural substances found in some foods, especially certain animal proteins.

If you form uric acid stones, your doctor or dietitian may tell you to limit:

• Red meat
• Organ meats, such as liver
• Shellfish
• Sardines
• Anchovies
• Meat-based gravies
• Alcohol, especially beer
• Sugary drinks, especially drinks with high fructose corn syrup

Your doctor or dietitian may suggest eating more fruits, vegetables, whole grains, and low-fat dairy foods. For some people, this may help make the urine less acidic and lower the chance of uric acid stones.

For struvite stones

Struvite stones are usually linked to urinary tract infections. They are not usually caused by diet alone.

If you form struvite stones, your care plan may focus on treating or preventing infections. Your doctor may also suggest drinking enough fluids to help keep urine flowing.

For cystine stones

Cystine stones are rare. They are caused by an inherited condition that allows too much cystine to build up in the urine.

If you form cystine stones, your doctor may suggest drinking more fluids to help dilute your urine. Some people may also need medicines or a special eating plan.

Before starting any vitamin, mineral, or herbal supplement, talk with your doctor or dietitian. Bring a list of everything you take, including over-the-counter supplements. Your care team can help you understand what may be safe for you.

Drinking enough water every day is one of the best ways to help prevent kidney stones. Water helps keep your urine diluted. This makes it harder for minerals to stick together and form stones.

A simple way to check if you are drinking enough is to look at the color of your urine. It should be light yellow or almost clear. If it is dark yellow, you may need to drink more water.

You lose water when you sweat, especially during:

• Hot weather
• Exercise
• Saunas
• Hot yoga

When you lose too much water, your body makes less urine. This gives stone-forming minerals more time to collect and form kidney stones.

Most people who have had kidney stones should aim to drink enough fluids to make at least 2 liters (about 8 cups) of urine each day. This usually means drinking about 8 to 12 cups of fluids throughout the day. Your doctor or dietitian can help you figure out how much is right for you.

Water is the best choice. Try to limit sugary drinks, regular soda, sweetened tea, and grapefruit juice because they may increase your risk of some types of kidney stones.

If you have kidney disease, heart disease, or have been told to limit how much you drink, ask your doctor how much fluid is right for you.

Regular physical activity is good for your overall health. It can help with weight, blood pressure, blood sugar, and heart health. These may matter for people who are at risk for kidney stones.

Exercise can also make you sweat. When you sweat, your body loses fluid. If you do not replace that fluid, your urine can become more concentrated. This may make kidney stones more likely to form.

You may need more water when you:

• Exercise
• Work outdoors
• Use a sauna
• Spend time in hot weather

To help stay hydrated:

• Drink water before, during, and after activity
• Take breaks when needed
• Check your urine color. Dark yellow urine may mean you need more fluid
• Ask your doctor about a safe fluid plan if you have kidney disease, heart disease, swelling, or have been told to limit fluids.

Vitamins and mineral supplements can affect people in different ways. Some may be safe for many people, but others may raise the chance of kidney stones in some people.

This can depend on:

• The type of kidney stone you have had
• Your urine test results
• Your kidney function
• Your other health conditions
• The dose of the supplement
• Other medicines or supplements you take

Some supplements may need extra caution, including:

• Vitamin C
• Vitamin D
• Calcium supplements
• Fish liver oils
• Mineral supplements that contain calcium

B vitamins, such as thiamine, riboflavin, niacin, B6, and B12, have not been shown to be harmful for most people with kidney stones. Some research has looked at vitamin B6 and urine oxalate levels, but this does not mean everyone with kidney stones should take it.

Ask before making big diet changes

Do not start a strict diet or cut out major food groups on your own. Some diet changes can help one type of kidney stone but may not help another type.

Ask your doctor or dietitian what diet plan is best for your type of kidney stone.

Key diet steps that may help prevent kidney stones

Your kidney stone prevention plan should be based on the type of stone you have, your urine test results, and your overall health. Some common diet steps may include:

• Drink enough fluids each day. Water is the best choice. Drinking enough fluid helps keep your urine diluted, which can lower the chance of stones forming.
• Limit sodium. Eating too much sodium can increase calcium in the urine, which may raise the chance of calcium stones.
• Eat the right amount of calcium. Do not cut out calcium unless your doctor tells you to. For some people, eating calcium-rich foods with meals may help lower the risk of calcium oxalate stones.
• Limit high-oxalate foods if needed. If you form calcium oxalate stones, your doctor or dietitian may suggest limiting foods that are high in oxalate, such as spinach, rhubarb, beets, nuts, chocolate, tea, or wheat bran.
• Do not overdo animal protein. Eating a lot of animal protein may raise the risk of some types of kidney stones, especially uric acid stones. 
• Ask before taking supplements. Some supplements, such as vitamin C, vitamin D, calcium, or mineral supplements, may affect kidney stone risk for some people.