In general, the best foods for kidney stones are foods that have low sodium and calcium contents; this is a broad category, but it typically includes most types of vegetables and lean meat. The worst foods, by contrast, include most berries, beans, and dark leafy greens. A lot also depends on what caused the stones in the first place. There are typically two broad types of kidney stones: those formed by calcium oxalate, and those formed by calcium phosphate. Both have nearly identical symptoms, but they can respond differently to different foods, and as such may require different diets. Getting an accurate diagnosis is one of the best places for people to start. Once the stone type has been identified, the patient’s care provider should be able to make more personalized recommendations.
Importance of an Accurate Diagnosis
What kidney stone patients are allowed to or advised to eat is often determined by the chemical composition of the stone itself. In nearly all cases, these sorts of buildups are caused by calcium. How that calcium solidifies often determines how it will respond to different elements in the blood, which in turn can help shape an effective diet — either for stone reduction or prevention.
Doctors often begin by recommending that patients avoid or at least reduce sodium in their diets. Sodium, also known more casually as salt, is often responsible for calcium buildups in the body. These buildups can cause stones to form where none were before, and can also make existing masses worse.
Processed or canned foods are some of the biggest sources of sodium. For example, a 6 inch (15.2 centimeter) hot dog can contain up to 1,046 milligrams of sodium, which is nearly half of the daily sodium intake recommended by most nutritionists. One of the best ways for a person to limit sodium is to avoid eating out or purchasing pre-made meals. Sometimes restaurants may add salt to enhance the flavor of certain foods or meals, but this can put a person over his daily sodium requirement. Cooking meals at home and avoiding the use of salt is one of the best ways to keep track of exactly how much is being consumed.
Precautions for Oxalate Stones
As for specific recommendations, food allowances vary. Good foods for kidney stones caused by calcium oxalate include most vegetables and meats like pork and lean beef, which should be eaten daily to improve overall health. There are a handful of foods that are bad for people prone to this type of kidney stones, however. Peanuts, beans and legumes, most berries, grapes, dark leafy vegetables, soy products, and citrus fruits are just some of the foods these people should usually avoid.
Calcium Phosphate-Specific Recommendations
People with calcium phosphate stones are usually able to enjoy a few more dietary freedoms. The goal here is usually to limit calcium intake so that the risk for kidney stones is low. Good foods for kidney stones include low-calcium foods and dairy alternatives, such as rice milk, which can be consumed daily. Avoiding milk, cheese, and yogurt is usually recommended. The plus side is that many dairy alternatives contain additional nutrients; the down side is that some may also contain higher than average sodium levels.
It is important that a person with this type of stone not completely eliminate calcium from his diet, however. Calcium is still essential for bone strength and the prevention of osteoporosis, especially for women. Dairy products can be consumed occasionally, as long as they meet the calcium restriction guidelines given by a nutritionist or medical doctor. People with calcium phosphate-specific kidney stones can usually also still enjoy other “off-limit” foods from time to time, so long as they are consumed in moderation.
Hydration and Common Pitfalls
Although it is not an actual food recommendation, hydration also plays a key role when it comes to kidney stones of any type. Water is an inexpensive way to stay hydrated throughout the day; flavored water and certain juices can also help. Not all beverages are good for kidney stones, however, especially if a person has a calcium oxalate stone. Clinical evidence shows that some carbonated beverages, cranberry juice, coffee, and tea contain oxalate, which can increase the risk for developing a buildup.