Low Oxalate Diet for Kidney Stone Prevention

Oxalate kidney stones are the most common kind of kidney stone. Oxalates are a compound found in foods, especially vegetables and nuts. In the normal processing of oxalate, calcium binds to the compound and is excreted in the stool. When there is not enough calcium or are too many oxalates, the excess oxalates are excreted through the urine by the kidneys. This is where oxalate kidney stones can become a problem.

Kidney stones are created when concentrated amounts of a substance, such as oxalates, continue to build up and compress into crystals which can then build up into solid masses, creating the stone. Being dehydrated aids in the creation of kidney stones because the urine becomes very concentrated and the kidneys are not cleared out efficiently, allowing for the buildup of oxalate crystals.

Diet and hydration are key in preventing kidney stones. It is recommended that people drink at least half of their body weight in ounces of water each day (150 lbs= 75 ounces). Anyone that is concerned about kidney stones should also try to limit salt in their diet. Higher salt intake affects the absorption of water and in turn the concentration of urine.

Following a low oxalate diet can also benefit people with kidney stones that contain oxalate. In order to determine if high oxalates are causing kidney stones a urine test, blood test, or testing of the kidney stone after passing can be done.

While following a low oxalate diet it is important to remember that cutting out all oxalates and calcium is not effective or healthy. Instead it is better to limit the amount of oxalate and calcium consumed. Including calcium in a meal that has higher oxalates is a great way to help prevent build up and be sure that there is enough calcium to efficiently bind to oxalates.

Some of the foods that are very high in oxalates and should be limited are; spinach, rhubarb, nuts and nut butters, beets, raspberries, pineapple, kiwi, white and sweet potatoes, buckwheat, miso, tahini, and Swiss chard.

Foods that are great to eat more of include; apples, bananas, arugula, kale, bok choy, cauliflower, cucumbers, oats, flax seed, fish, eggs, and watermelon.

For a more complete list of low, moderate, and high oxalate foods check out the Harvard Oxalate List.

Not sure about starting a low oxalate diet? Try out this simple recipe from The Kidney Dietician!