What is an oxalate-controlled diet for kidney stones?
If your doctor has ordered a diet to help you decrease the chances of forming calcium oxalate kidney stones. Oxalate is a compound that is naturally present in many foods.
What are kidney stones?
A kidney stone normally begins as a small crystal-like material and it gradually builds up into a larger, solid mass. Urine normally contains chemicals that inhibit the crystals from forming. Or, if crystals remain small enough they can travel through the urinary tract and pass out of the body without being noticed. However, when crystals combine together to form a kidney stone, it can stick to the lining of the kidney or settle in an area where urine cannot carry it out of the body.
Who would benefit from an oxalate-controlled diet?
Calcium oxalate stones are the most common type of kidney stone. As such, many patients with kidney stones can benefit from a diet that reduces calcium kidney stones. However, if you don't test high for oxalate, this diet will not benefit you. Ask your Cleveland Clinic physician if an oxalate controlled diet would be helpful to you.
Six steps to control oxalate for kidney stones
The following six steps can be taken to reduce the risk of forming calcium oxalate stones:
1. Eat fewer high-oxalate foods.
The first suggestion is the most obvious. The more oxalate that is absorbed from your digestive tract, the more oxalate in your urine. High-oxalate foods to limit, if you eat them, are:
- Bran flakes
- Potato chips
- French fries
- Nuts and nut butters
You do not need to cut out other healthy foods that provide some oxalate. In fact, oxalate is practically unavoidable, because most plant foods have some. Often a combination of calcium from foods or beverages with meals and fewer high-oxalate foods is required.
2. Increase the amount of calcium in your diet.
Low amounts of calcium in your diet will increase your chances of forming calcium oxalate kidney stones. Many people are afraid to eat calcium because of the name "calcium oxalate stones." However, calcium binds oxalate in the intestines. A diet rich in calcium helps reduce the amount of oxalate being absorbed by your body, so stones are less likely to form. Eat calcium rich foods and beverages every day (2 to 3 servings) from dairy foods or other calcium-rich foods.
Also, eating high calcium foods at the same time as high oxalate food is helpful; for example have low fat cheese with a spinach salad or yogurt with berries. If you take a calcium supplement, calcium citrate is the preferred form.
3. Limit the vitamin C content of your diet.
Oxalate is produced as an end product of Vitamin C (ascorbic acid) metabolism. Large doses of Vitamin C may increase the amount of oxalate in your urine, increasing the risk of kidney stone formation. If you are taking a supplement, do not take more than 500 mg of Vitamin C daily.
4. Drink the right amount of fluids every day.
It is very important to drink plenty of liquids. Your goal should be 10-12 glasses a day. At least 5-6 glasses should be water. You may also want to consider drinking lemonade. Research suggests that lemonade may be helpful in reducing the risk of calcium oxalate stone formation.
5. Eat the right amount of protein daily.
Eating large amounts of protein may increase the risk of kidney stone formation. Your daily protein needs can usually be met with 2-3 servings a day, or 4 to 6 ounces. Eating more than this if you are at risk at kidney stones is unnecessary.
6. Reduce the amount of sodium in your diet.
Reduce the amount of sodium in your diet to 2-3 grams per day. Limit eating processed foods such as hot dogs, deli meats, sausage, canned products, dry soup mixes, sauerkraut, pickles, and various convenience mixes.
Use the ChooseMyPlate.gov web site to plan a well-balanced diet. Carbohydrates, proteins, and fats are necessary for the proper functioning, maintenance, and repair of your body. In addition to these major nutrients, the body requires water, minerals, and vitamins for good health.
- Academy of Nutrition and Dietetics. Nutrition Care Manual Accessed 2/17/2015.
- US Department of Agriculture. ChooseMyPlate.gov Accessed 2/17/2015.