Patient education: Kidney stone diet (The Basics)

What are kidney stones? — Kidney stones are just what they sound like: small stones that form inside the kidneys. They form when salts and minerals that are normally in the urine build up and harden. They can be made of different substances.

Kidney stones usually get carried out of the body when you urinate. But sometimes, they can get stuck on the way out (figure 1). If this happens, it can cause:

●Pain in your side, back, or in the lower part of your belly

●Blood in the urine (which can make urine pink or red)

●Nausea or vomiting

●Pain when you urinate

●Needing to urinate in a hurry

Why do I need a special diet? — Depending on what your stones are made of, changing your diet might help lower the chances of new stones forming.

Your doctor or nurse might recommend diet changes as part of your treatment plan if you have:

●Calcium oxalate stones – When your body digests certain foods, it makes a waste product called "oxalate." If you have too much oxalate in your urine, crystals can form and stick together to make a kidney stone.

●Uric acid stones – When your body digests substances called purines, which are found in some foods, it makes a waste product called "uric acid." Kidney stones can form when too much uric acid builds up in your body.

●Other types of stones – Your body needs a balance of the right amounts of fluids and minerals to work well. Changes in certain minerals or how much you drink can affect your risk of kidney stones.

What can I eat and drink on a kidney stone diet? — There is no specific diet plan to prevent kidney stones. Foods that are good to eat for 1 type of kidney stone might not be good to eat with another type of kidney stone. Your diet recommendations might be based on the exact type of kidney stone you have.

General recommendations include:

●Eat healthy – Try to eat a healthy diet with plenty of vegetables, fruits, whole grains, and low-fat dairy products. It might help to add extra fruits and vegetables, especially those that are high in potassium.

●Get plenty of fluids – Drinking more water throughout the day is one of the best ways to help lower your risk of all types of kidney stones.

●Limit salt – Limiting the amount of salt in your diet can also lower the risk of kidney stones. Salt is also called "sodium."

Some foods that are generally OK to eat:

●Grains – Whole-grain breads, pastas, cereals, rice, English muffins, and bagels. Cooked hot cereals such as oatmeal and cream of wheat (not instant cereals). Unsalted crackers and snack foods.

●Fruits – Most fresh, frozen, or canned fruits in their own juices. Fruit juices without added sugar, cherries, oranges, melons, peaches, pears, kiwi, apples, papaya, bananas. Dried fruit without added sugars.

●Vegetables – Fresh or frozen vegetables, canned vegetables without salt, potatoes, tomatoes, squash, bell peppers, beets, carrots, beans.

●Dairy – Low-fat or fat-free milk, yogurt, and cheese.

●Meats, poultry, seafood, and proteins – Eat a moderate amount of protein. Good sources of protein for most people with kidney stones include dried beans, peas, lentils, tofu, and walnuts. Other nuts and nut butters might be good sources of protein to eat, based on the kind of kidney stone you have.

●Condiments and other foods – Fresh or dried herbs, lemon juice, seasonings without salt, mustard, vinegar, hot sauce.

●Fluids – Drink plenty of fluids such as water, unsweetened tea, and coffee.

What foods and drinks should I avoid or limit on a kidney stone diet? — Depending on what type of kidney stone you have had, limiting certain foods might help lower the risk of new stones forming.

For example:

●Calcium oxalate stones – Limit foods and drinks with a lot of oxalate. Examples include spinach, rhubarb, strawberries, chocolate, almonds, peanuts, pecans, beets, tea, whole-wheat products, non-dairy animal proteins like meat and eggs, and foods high in added sucrose and fructose, which are types of sugar. Do not take vitamin C or calcium supplements.

●Uric acid stones – Limit foods with purines. Examples include oats, whole milk and whole-milk products, asparagus, spinach, and certain meats, fish, and poultry.

Your doctor or nurse can talk to you about whether it makes sense to avoid or limit certain foods. It can also help to work with a dietitian (food expert). They can help you make sure that your body is getting the nutrients it needs.

What else should I know? — Getting the right amount of calcium in your diet is important for healthy bones. But having too much or too little calcium can cause some types of kidney stones to form. Talk with your doctor, nurse, or dietitian about how much calcium you should have. Talk to them before taking calcium or vitamin D supplements.

Depending on your weight and health, it might help to try to lose weight. Keeping a healthy body weight can help prevent kidney stones.

More on this topic

Patient education: Kidney stones in adults (The Basics)
Patient education: Kidney stones in children (The Basics)
Patient education: Low-sodium diet (The Basics)
Patient education: Low-purine diet (The Basics)

Patient education: Kidney stones in adults (Beyond the Basics)
Patient education: Kidney stones in children (Beyond the Basics)
Patient education: Low-sodium diet (Beyond the Basics)