Citric Acid and Kidney Stones
What is it? How can it help?
Citric acid is a natural part of many fruits. It is not a vitamin or mineral and is not needed in the
diet. However, citric acid may be helpful for people who form calcium kidney stones,
particularly those with a low amount of citrate in their urine. The more citrate in your urine, the
more protected you are against forming calcium kidney stones.
How does citric acid protect against kidney stones?
Citrate in your urine slows formation of calcium stones by preventing tiny crystals from joining
together to form bigger ones. Citric acid from food is only helpful for preventing calcium-
containing stones. It does not help prevent other stone types such as uric acid stones.
If your urinary citrate is very low, you may need a prescription for a stronger form of citrate.
Prescription doses of potassium citrate can help prevent stones. Treatment may be costly and
require as many as 12 tablets daily.
What are the best food sources of citric acid?
Lemons and limes have the most citric acid. Oranges, grapefruits, and berries also contain
large amounts. Many other fruits and vegetables contain a small amount of citrate, too. A half
cup (4 ounces) of pure lemon or lime juice per day provides about the same amount of citric acid
as the prescription form. Lemon or lime juice can either be squeezed fresh from the fruit or
purchased as a concentrate in a bottle.
Does lemonade count?
No! Lemonade has only a small amount of actual lemon juice diluted in water and sugar. It is
not the same as pure lemon juice. Drinking regular or non-“diet” lemonade will only add
needless sugar and calories to your diet.
Along with increasing citric acid in your diet, drinking enough fluids (at least ten 8-ounce
glasses per day) may be the best way to decrease your risk of new calcium stones.
10 Tips to increase citric acid in your diet:
1. Although citrus fruits are the best source of citric acid, all fruits and vegetables will
increase the citric acid in your urine and provide other health benefits as well. For
example, potassium and magnesium protect against forming new stones and may prevent
cancer and other chronic diseases. Try for 5 or more servings per day!
2. Make lemon-lime ice cubes. Fill ice cube trays almost full with water. Then squeeze at
least half of a lemon and/or lime over the ice cube trays before freezing. Juice concentrate
can also be used. Use these ice cubes to spruce up plain tap water and other beverages.
3. Squeeze some fresh lemon or lime directly into your soda, fruit juice, tea or water.
4. Chug it! Dilute 2 ounces lemon juice with 6 ounces water and drink twice a day – once in
the morning and once in the evening – to reach the goal of 4 ounces lemon juice per day.
Here’s a quick tip to get more juice from lemons & limes:
Roll them on a hard surface while pressing down with your
palm. Or, heat them for about 30 seconds in the
microwave before squeezing.
5. Lemonade isn’t just for summer! Make homemade lemonade by squeezing a ½ cup (4
ounces) of fresh or bottled lemon juice into a pitcher of cold water. Add sugar or sugar
substitute, if desired. If you are watching calories or sugar, there are non-caloric lemonade
products (such as Crystal Light or Minute Maid Light) that are high in citric acid but have
much less sugar and few or no calories. Check the labels before buying to be sure citric acid
appears near the top of the ingredient list.
6. Make a lemon spritzer. Pour 2 cups fresh lemon juice (from about 9 medium size lemons;
or use lemon juice concentrate) into a large pitcher. Add 1 cup Splenda®, a no-calorie
sweetener made from sugar. When Splenda® is fully dissolved, add 1 liter chilled club
soda, thin slices from 2 limes, and a few ice cubes. Stir and serve.
7. Use fresh lemon on lettuce or spinach salads. You may find yourself using less of those
high-fat salad dressings!
8. Use freshly squeezed lemon or lime on fruit salads. Besides adding a zesty taste, the acid
in the juice will prevent cut fruits, such as apples, from browning. You’ll have better-
looking and healthier fruit salads.
9. Use lemon or lime juice on fish and in marinades for any type of meat. When looking
for marinades and other recipes, try ones that call for lemon or lime juice, and work them
into your menus at home.
10. Let the label be your guide. Choose products that are high in citric acid. Some lemon-
lime sodas, for example, can be high in citric acid. If you drink soda, consider switching to
a brand that is high in citric acid.
What is the most important thing you learned from this handout?
What changes will you make in your diet/lifestyle, based on what you learned today?
If you are a UW Health patient and have more questions please contact UW Health at one of the
phone numbers listed below. You can also visit our website at www.uwhealth.org/nutrition.
Nutrition clinics for UW Hospital and Clinics (UWHC) and American Family Children’s
Hospital (AFCH) can be reached at: (608) 890-5500. Nutrition clinics for UW Medical
Foundation (UWMF) can be reached at: (608) 287-2770.
Your health care team may have given you this information as part of your care. If so, please use it and call if you
have any questions. If this information was not given to you as part of your care, please check with your doctor. This
is not medical advice. This is not to be used for diagnosis or treatment of any medical condition. Because each
person’s health needs are different, you should talk with your doctor or others on your health care team when using
this information. If you have an emergency, please call 911. Copyright 2/2015 University of Wisconsin Hospital and
Clinics Authority. All rights reserved. Produced by the Clinical Nutrition Services Department and the Department of