Nutrition Tips for Preventing Kidney Stones
Kidney stones are hard deposits of crystalized minerals and salts that form when urine becomes too concentrated. They come in different sizes and can affect any part of the urinary tract.
Kidney stones are very common and can affect adults and children. Some risk factors that increase the chances of developing kidney stones are:
- Diets high in animal protein, sodium and sugar
- Certain medications and supplements (specifically taking ≥1,000 mg/day of vitamin C supplements)
- Genetics (personal or family history of kidney stones)
medical conditions such as:
- Dent disease (a rare genetic kidney disorder almost exclusive to males)
- Renal tubular acidosis
- Inflammatory bowel disease (IBD) and Crohn’s disease
- Gastric bypass surgery
Types of Kidney Stones
If you have a kidney stone, knowing the type can help determine the cause and how to prevent future ones.
Calcium oxalate stones are the most common type of kidney stone. They form when there is too much oxalate or calcium in the urine.
Calcium phosphate stones usually occur in people with certain medical conditions such as renal tubular acidosis or people taking certain medications for the treatment of migraines or seizures.
Uric acid stones can have a variety of causes. A diet high in purine, a natural chemical compound found in meats, meat products and organ meats increase uric acid production. Dehydration, diabetes and chemotherapy could also increase the risk of uric acid stones.
Struvite stones are caused by a bacterial urinary tract infection (UTI).
Cystine stones develop in people with cystinuria, a rare hereditary condition that causes a buildup of cystine, an amino acid, in the urine.
8 Diet Tips to Decrease Risk of Kidney Stones
Nutrition can play a major role in the prevention and management of kidney stones.
1. Stay hydrated
Proper hydration is recommended for preventing all types of kidney stones. Adequate water or fluid intake helps the kidneys flush out waste products and other minerals before a stone can form. Talk with your doctor or dietitian about how much and which types of fluids you should be drinking each day.
2. Limit animal protein and purine
Animal protein is thought to contribute to kidney stone formation by increasing the level of uric acid in the urine. Many animal protein sources are also high in purine—a natural chemical compound found in red meat, organ meats, shellfish, sardines, anchovies, and beer or alcoholic beverages. The National Kidney Foundation recommends a daily protein intake of 0.8 to 1.4 grams per kilogram (g/kg) body weight. Other research provides guidelines specific to animal protein, recommending limiting animal protein intake to 0.8 to 1 g/kg/day to decrease stone risk. Talk with your dietitian about how much protein you should be eating each day.
Lacto-ovo vegetarian diets which include dairy products and eggs have been shown to help prevent kidney stones. However, vegan and ovo-vegetarian diets may lead to certain nutrient deficiencies which can increase stone risk. Talk with your doctor or dietitian to see if you may benefit from taking certain vitamins or supplements to help you meet your daily micronutrient needs.
3. Limit sugar
Diets high in sugar, particularly fructose, have been shown to increase kidney stone risk. Sodas and other sugar-sweetened drinks often contain high-fructose corn syrup. Natural sources of fructose include honey, as well as certain fruits and vegetables (e.g., apples, grapes, watermelon, asparagus, peas, zucchini). Fructose is also found in table sugar.
4. Limit sodium
High sodium or salt intake increases kidney stone risk. While the National Kidney Foundation recommends limiting sodium intake to 2,000 to 3,000 mg/day, the Dietary Approaches to Stop Hypertension (DASH) diet and Dietary Guidelines for Americans recommend ≤2,300 mg/day. Intake as low as 1,500 mg/day is recommended for certain individuals.
5. Limit oxalate
Oxalate is a natural compound found in many foods. Because many healthy foods contain oxalate, it is only recommended to limit or avoid foods with high or very high oxalate content. Rhubarb, spinach and rice bran contain a very high amount of oxalate at >200 mg/serving. Almonds, beans, beets, cocoa powder, corn meal, miso soup, okra, potatoes (with skin), wheat and oat bran, bran cereals, quinoa and amaranth all contain a high amount of oxalate at >50 mg/serving.
Eating oxalate-rich foods the same time as calcium-rich foods can decrease stone risk. However, for those limiting dairy foods in their diet, taking a calcium citrate supplement at that meal may be beneficial. Speak with your doctor or dietitian to determine if you could benefit from a calcium supplement.
6. Limit phosphorus
Decreasing dietary phosphorus intake should be considered for the prevention of calcium phosphate stones. Organic phosphorus is a mineral naturally found in animal protein sources such as meats, poultry, fish, beans, nuts and dairy products. Inorganic phosphorus is also used as an additive or preservative in many processed foods, fast foods, and canned or bottled drinks, especially dark sodas. Inorganic phosphorus is completely absorbed by the body, so it is recommended to limit intake as much as possible. Organic phosphorus is not fully absorbed, so current recommendations are to decrease intake of these organic phosphorus-containing foods by one-third.
7. Consider the DASH diet
The Dietary Approaches to Stop Hypertension (DASH) diet is well known for its heart health benefits and has shown possible benefits in reducing kidney stones. The DASH eating plan is rich in potassium and calcium, promoting a high intake of fruits and vegetables and a moderate intake of low-fat or fat-free dairy products. Animal protein sources low in saturated fat, such as lean meats, poultry and fish, should be limited to ≤6 oz per day. Sodium intake is restricted to 1,500 to 2,300 mg/day depending on individual needs. The diet also involves limiting sweets and sugar-sweetened beverages.
8. Manage your weight with physical activity
Obesity and its associated comorbidities can increase kidney stone risk. Combined with healthy diet changes, mild to moderate physical activity can help you achieve a healthier weight and decrease the risk of many other comorbidities.
Kidney stones, while often very painful, usually result in no permanent damage to the urinary tract if treated properly. Staying hydrated and making certain diet changes are the main way to prevent kidney stones. Talk with your doctor or dietitian to find out which dietary recommendations and vitamin or mineral supplementation, if needed, could benefit you.
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Additional Kidney Diet Resources
Visit DaVita.com and explore these diet and nutrition resources:
This article is for informational purposes only and is not a substitute for medical advice or treatment. Consult your physician and dietitian regarding your specific diagnosis, treatment, diet and health questions.