Kidney Health: Citric Acid and Kidney Stones
What is it? How can it help?
Citric acid is an organic acid and a natural part of many fruits and fruit juices. It is not a vitamin or mineral and is not needed in the diet. However, citric acid, not to be confused with ascorbic acid (vitamin C), may be helpful for people with calcium kidney stones. It slows stone formation and prevents tiny crystals from joining together to form bigger ones. The more citric acid in your urine, the more protected you are against forming kidney stones. Citrate, used in calcium citrate supplements and in some medicines (such as potassium citrate), is closely related to citric acid and also prevents stones. Citrate may be prescribed to make your urine more alkaline.
How does citric acid protect against kidney stones?
Citric acid makes it harder for calcium containing stones to form in your urine. Citric acid from lemons or limes is not effective for preventing uric acid or other types of stones. It does not make your urine more alkaline as citrate does. Rather, it prevents small stones from becoming “problem stones” by stopping other material from attaching and building onto the stones.
What are the best food sources of citric acid?
Citric acid is most common in citrus fruits and juices. Of these fruits, lemons and limes have the most citric acid. While oranges, grapefruits, and berries also contain large amounts, lemons and limes will most add the most to the citric acid content of your urine. While pharmacological doses of citric acid prescribed as potassium citrate are helpful in the treatment of stones, treatment may be costly and awkward, needing as many as 12 tablets daily. A half-cup (4 ounces) of pure lemon juice per day provides about the same amount of citric acid as does pharmacological therapy.
Does lemonade count?
No! Lemonade is only a small amount of actual lemon juice dilluted in water and sugar. It is NOT the same as pure lemon juice that comes from the fruit. Drinking lemonade, unless it is artificially sweetened or "diet," will only add unnecessary sugar and calories to your diet.
Keep reading for tips to increase your citric acid intake and lessen your risk for getting kidney stones. In addition to increasing citric acid in your diet, drinking enough fluids (at least ten 8-ounce glasses per day) may be the most great way to decrease your risk of new stones.
10 Tips to increase citric acid in your diet
1. As lemons and limes provide the most citric acid per gram, these tips focus on them. Remember that increasing your intake of all fruits and vegetables – in particular citrus – will add to your citric acid intake and provide other health benefits as well. For example, the potassium and magnesium contained in fruits and vegetables protect you against forming new stones and may prevent cancer and other chronic diseases, too. Try for 5 or more servings per day!
2. Squeeze fresh lemon (or reconstituted lemon juice) into ice cube trays before freezing. Fill trays almost full with water. Then, squeeze half a lemon or more over the tray. Use these lemon cubes for sprucing up plain tap water and other beverages. If you like the taste of lime, use lime instead of, or in addition to, lemons. Remember to drink at least 10 glasses of fluid every day in order to keep your urine dilute enough to prevent stones.
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.
5. Lemonade isn’t just for summer! Make homemade lemonade by squeezing a ½ cup (4 ounces) of fresh lemon juice into a pitcher of cold water; bottled lemon juice may also be used. Add sugar or sugar substitute, if desired. Make it by the glass for a single serving. Or, make lemonade from frozen concentrates or powdered mixes. Check the labels before buying to be sure citric acid appears as a main ingredient (ingredients are listed in descending order of concentration). If you are watching calories or sugar, there are non-caloric powdered lemonade mixes and beverages (such as Crystal Light or Minute Maid Light) that are high in citric acid but have much less sugar and few or no calories.
Here’s a tip to get more juice from lemons: roll them on a hard surface while pressing down with your palm. Or, heat them for about 30 seconds in the microwave before squeezing.
6. Make a lemon spritzer. Here’s how: 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 lime slices from 2 limes, and a few ice cubes. Stir and chill thoroughly before serving.
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 with exposure to air. 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 the 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, are relatively high in citric acid. If you drink soda, consider switching to the one that is high in citric acid.
If you have questions, contact UW Health Clinical Nutrition at one of the following locations:
UW Health West Clinic
UW Health East Clinic
The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Any duplication or distribution of the information contained herein is strictly prohibited.
Last Updated: 11/09/2012
Copyright © 11/09/2012 University of Wisconsin Hospitals and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#353
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