Kidney stones are small, hard deposits that form in the kidneys when there is a decrease in urine or an increase in certain substances, such as minerals and salts.
Fortunately, dietary changes as laid out in the kidney stone diet can help prevent kidney stones from forming or recurring.
- By including certain foods in a diet, kidney stones may be prevented or delayed.
- No one set type of diet will prevent all kidney stones since different dietary factors can cause different types of kidney stones.
- Kidney stones are classified according to the type of material that casues them.
- By limiting certain foods in the diet, a person may be able to prevent kidney stones developing.
What is a kidney stone?
A kidney stone is a formation of minerals that may be caused by a range of factors.
When urine decreases and certain minerals in the kidneys are abundant, the minerals stick together and form stones.
There are several types of common stones. Common kinds of kidney stones include the following:
- calcium oxalate stones
- calcium phosphate stone
- struvite stones
- uric acid stones
- cystine stones
A range of factors can cause kidney stones, including the following dietary factors:
- high oxalate intake from certain foods
- a high protein diet
- too much sodium
- dehydration or low fluid intake
High oxalate foods, such as nuts, seeds, beets, spinach, and buckwheat flour can contribute to calcium oxalate stones, although this does not mean that people need to exclude them from their diet completely. A high protein diet can contribute to the formation of calcium phosphate stones. A high sodium intake and dehydration can be factors in uric acid and cystine stones.
What is the kidney stone diet?
To avoid a recurrence of kidney stones, or to prevent them developing in the first place, people should drink plenty of water, limit salt and animal protein, limit foods high in oxalates, and be cautious about taking too much calcium in supplements.
While there is no one diet for all types of kidney stones, many dietitians and nephrologists (kidney doctors) recommend the DASH (Dietary Approaches to Stop Hypertension) diet for people with kidney stones. This diet has been shown to reduce the risk of kidney stone formation as well lower blood pressure and decrease risk for heart disease, stroke, and cancer. The DASH diet encourages the consumption of vegetables, fruits, whole grains, and low-fat dairy. It limits the intake of sodium, sugar, and red meat.
Foods that may prevent kidney stones
Because kidney stones vary according to what they are made of, the foods to include in a diet will vary. A person should talk to their doctor about which foods cause stones to help them determine what they should and should not eat to help avoid the formation of stones in the future.
The following are some suggestions on what to include in a diet to avoid the formation of stones.
Calcium and oxalate-rich foods
Foods rich in calcium, such as milk-based products, are recommended to help reduce kidney stones.
A person should include foods rich in calcium, particularly if consuming foods that are higher in oxalate such as spinach. The calcium and oxalate bind together in the intestines, reducing the formation of stones.
Some foods to include are:
- milk-based products
- calcium fortified foods, such as cereal, bread, and juices
- beets on a spinach salad with low-fat cheese
- yogurt with berries
Fruits and vegetables
Fruits and vegetables are a necessary part of any diet. Increasing the amount of vegetables in their diet can help a person prevent stone formation. Fruits can be dried, frozen, or fresh. Fruits rich in citric acid have also been shown to have a positive effect in preventing kidneys stones. Get to know the particular fruits and veggies that have high oxalate content and try to limit them, or be sure to eat them in combination with calcium-rich foods.
Including extra water in the diet can help prevent the formation of both uric acid and cystine stones. Including other liquids in addition to water is acceptable; however, it is important to check sodium levels in the beverage.
Small amounts of animal-based proteins are fine. However, too much animal protein can increase the risk of developing kidney stones. Plant-based protein sources, however, are encouraged. Examples include beans, peas, and lentils. People should discuss their individual protein needs with a doctor or a dietitian, as needs will vary from person to person.
Foods to limit with kidney stones
A dietician or doctor will provide diet details that may include limiting pork and beef, amongst other food sources.
What food to limit depends on what type of stone is developing in a person's body.
Foods to limit, include:
- animal proteins, including eggs, fish, pork, beef, and milk products
Every person is different, and individual needs and dietary requirements will vary. A dietitian or doctor can provide more specific diet details based on individual needs.
Why do some foods prevent kidney stones?
Some foods contain certain chemicals or compouds that can influence the production of kidney stones, particularly if eaten in high amounts.
By limiting intake of these foods, the likelihood of kidney stones forming or worsening is reduced.
Can kidney stones be treated through diet alone?
In some cases, dietary changes may be enough to prevent kidney stones from occurring. In other cases, additional treatment including medication to break the stones up or surgery to remove the stones may be needed.