Diet and Kidney Stones

What diet do I need to follow?

To reduce the chance of stone formation, INCREASING YOUR FLUID INTAKE is the most important strategy.

You should also REDUCE the following, which can increase the chance of new stones:
SALT
ANIMAL PROTEIN
OXALATE

Diet and medications may be adjusted depending on the composition of your kidney stones.  The most common types of stone contain calcium oxalate, uric acid and calcium phosphate which tend to respond better to dietary interventions compared to rare stone types like cystine and struvite.

1. FLUIDS

Your should increase fluid intake to at least 10-12 cups (2.5 to 3 liters) per day.  The goal should be to produce around 2.5 L of urine per day. This will help dilute the crystal concentration in the urine and help prevent stone formation.  Half of the fluid you drink should be water. 

In hot, humid weather conditions or with major physical exercise such as heavy work or sport activities you should drink more. 

It is important that your fluid intake is distributed equally over 24 hours.  For example, you should drink throughout the course of the day and before going to bed. 

What beverages should I drink?

Water is the best fluid. Other fluids such as milk, juice, and soup count towards your intake. Try to limit drinks with added sugar like pop, sweetened iced tea, fruit drinks and sports drinks.

Avoid: black tea, iced tea, COLAS, Root Beer, cocoa based beverages and grapefruit juice.

2.  SODIUM & SALT

A high salt content in your diet (added salt and/or salty foods) increases the risk of stone formation by increasing the excretion of calcium in the urine.  On the other hand, a drastic reduction of salt in your diet might decrease the amount of urine you produce.  Therefore, a moderately reduced salt intake is recommended. The goal should be 1500 mg daily and not more than 2300 mg a day (1 teaspoon).  To control the amount of salt in your diet, limit the use of the following foods:

  • Table salt
  • Spices, including garlic and onion seasonings, “Nu-salt”, MSG
  • Condiments                                                                                   
  • Sauerkraut, olives, dill pickles
  • Soy sauce, steak and Worcestershire sauce, chili sauce, gravy, ketchup
  • Most cheeses    

When preparing your meals try to reduce the amount of salt.  Instead of salt, try using herbs, spices, fresh or powdered onion and garlic, “Mrs. Dash” or McCormick’s “no salt added”, and lemon juice as flavor enhancers.

Highly Salted Foods:

  • Bouillon cubes
  • Canned vegetables and vegetable juices                
  • Processed cheese such as cheese spreads and  single slice cheese                   
  • Canned and powdered soups                                                 
  • Frozen dinners                                                                             
  • Prepared, processed and most fast foods
  • Pickled and salt-cured foods       
  • Salted snack foods: crackers, chips, nuts, pretzels         
  • Restaurant food  

3. OXALATE

Foods high in oxalates should be limited, especially if tests show high oxalate in your urine.

     Very high oxalate foods:

  • Spinach, dark green leafy vegetables, beet greens
  • Potatoes, beets, rhubarb, turnip
  • Nuts, sesame seeds, peanut butter, chocolate, wheat bran
  • Soy products, tofu
  • Cranberry pills
  • Vitamin C (if > 1000 mg per day)

     High oxalate foods:

  • Beer
  • Berries: blackberries, gooseberries, black raspberries, strawberries
  • Beans (wax, baked or legumes), summer squash, eggplant, leeks, celery
  • Cocoa powder, chocolate
  • Concord grapes, red currants, peel of lemons, lime and orange
  • Wheat germ, whole-wheat flour, grits (white corn)

4. ANIMAL PROTEIN AND PURINE-RICH FOOD INTAKE

Purines, especially from animal protein sources, form uric acid crystals in the urine.  This can lead to kidney stone formation.  It is recommended that you limit your daily intake of meat, fish, poultry and eggs to 2-3 servings of 2 1/2 oz (75 grams) a day.

Limit the following high purine foods:

  • Organ meats: liver, kidney, brain, sweetbreads, calf tongue
  • Meat extracts, meat broth, bouillons and consommés, gravy and mincemeat
  • Sardines, herring, mackerel, scallops, mussels, canned salmon, caviar or roe, anchovies
  • Game meats: goose, duck and partridge

5.  CITRATE

Citrate binds calcium in your urine and can be incorporated into your diet to prevent stone formation.  Citrate is commonly found in fruit juices. 

Beverages with desired citrate concentration e.g. reconstituted lemon juice (add 4 ounces of lemon juice to two liters of water each day).

6.  CALCIUM

Calcium and Vitamin D are required to maintain healthy bones.  Therefore, it is important to include enough calcium in your diet, aiming for 2-3 servings or Mild and Alternatives daily.  Contrary to previous beliefs of calcium leading to stone formation, you should NOT restrict your dietary calcium intake. The intake of calcium should be 1000-1200 mg per day separated into 2 doses and ideally with meals. Calcium is ideally obtained through diet which should include a minimum of 3 servings of calcium-rich foods.

Try to include the following high calcium foods in your diet:                                                                      

  • Dairy products. Examples of one serving:
    1 cup (250 mL) of milk
    3/4 cup (175 mL) of yogurt
    1 1/2 oz (50 grams) of cheese
  • Calcium fortified beverages such as orange juice

7. FRUITS AND VEGETABLES

A diet high in fibre, fruits, and vegetables may offer a small protective effect against stone formation.

References

Can Urol Assoc J 2016; 10(11-12): E347-58. CUA guideline on the evaluation and medical management of the kidney stone patient – 2016 update.
Diet and Kidney Stone Information Handout supported by an unrestricted educational grant   from Seaford Pharmaceuticals Inc 1-888-292-3192 http://www.seaford.ca

Living Healthy Fight Kidney Stones with Food Cookbook (Urology Care Foundation)Download