Oxalates are naturally occurring compounds found in many foods, and in some individuals, high levels of oxalates can contribute to the formation of kidney stones. To understand the impact of oxalates on the body, it’s important to know what they are and how they’re metabolized.
What Are Oxalates?
Oxalates, also known as oxalic acid, are compounds that can combine with calcium to form crystals. These crystals can then form kidney stones in susceptible individuals. When oxalates are metabolized, they’re broken down in the gut and then excreted through the urine. However, if an excessive amount of oxalates is consumed and the body isn’t able to break them down and excrete them effectively, the crystals can build up and form kidney stones.
Foods High in Oxalates
It’s important to know which foods contain high levels of oxalates so that you can make informed decisions about what to include in your diet. You can also read about which foods have low levels of oxalates.
Foods high in oxalates include:
- Spinach: One cup of cooked spinach contains approximately 1.2 grams of oxalates. Spinach is a leafy green vegetable that is also a good source of vitamins and minerals, but it’s high oxalate content should be considered by people at risk of kidney stones.
- Beet greens: One cup of cooked beet greens contains approximately 1.4 grams of oxalates. Beet greens are the leaves of the beet plant, which are often consumed cooked or in salads, high in oxalate content and should be limited for people who are at risk of kidney stones.
- Sweet potatoes: One medium sweet potato contains approximately 0.5 grams of oxalates. Sweet potatoes are a good source of potassium, vitamin A and fiber, but are also high in oxalates, so they should be consumed in moderation by those who are at risk of kidney stones.
- Nuts: Nuts such as almonds, pecans, and peanuts contain high levels of oxalates, with approximately 0.5-1 grams per 1/4 cup serving. Nuts are a good source of protein and healthy fats, but their oxalate content should be taken into account by people at risk of kidney stones.
- Rhubarb: One cup of raw rhubarb contains approximately 1 gram of oxalates. Rhubarb is a vegetable that is often used in pies, jams and jellies, high oxalate content should be considered by those who are at risk of kidney stones.
- Chocolate: Chocolate contains moderate to high levels of oxalates, with one ounce of unsweetened chocolate containing about 0.5 grams of oxalates. Chocolate is a common food that is high in oxalate, so it should be consumed in moderation by people at risk of kidney stones.
- Berries: Some berries such as raspberries, blackberries and strawberries contain moderate amount of oxalates, around 0.2 – 0.4 grams per cup. Berries are a good source of antioxidants, vitamins and minerals, but people at risk of kidney stones should limit their consumption.
It’s important to note that the oxalate content of foods can vary depending on factors such as growing conditions, preparation methods, and the specific type of food. Therefore, it’s a good idea to consult a registered dietitian or a nutritionist to get more specific and accurate information on the oxalate content of foods.
Managing Oxalate Intake
To manage oxalate intake, several strategies can be employed. Reducing the consumption of high-oxalate foods is the most obvious approach. Consuming calcium-rich foods such as milk, cheese, and yogurt can also help to reduce the formation of kidney stones.
It’s also important to drink plenty of water, as staying hydrated helps to flush oxalates out of the body. For people who are at high risk of kidney stone formation, a registered dietitian can help create an individualized plan for managing oxalate intake.
Although high oxalate intake can contribute to kidney stone formation, it is important to remember that most people can consume high-oxalate foods in moderation as part of a balanced diet.
By understanding which foods contain high levels of oxalates, and managing oxalate intake through a combination of diet and hydration, you can minimize your risk of kidney stones.
If you have a history of kidney stones or are at high risk, working with a registered dietitian can help you create an individualized plan for managing oxalate intake.
Barbara Weiss is a highly accomplished health expert with over 20 years of experience in the field. She is a certified physician assistant and a member of multiple professional organizations, including the American Academy of Physician Assistants.