Oxalate is a naturally occurring substance found in plants and animals. It is found in certain foods that you eat and is also made in your body. Most people do not need to be concerned about the oxalate in their diet. However, if you have ever had a calcium oxalate kidney stone, your doctor may have recommended that you follow a low-oxalate diet to help lower your risk of developing another painful kidney stone. In this article, we will discuss the role of oxalates in kidney health, provide tips on how to reduce your intake, and give you some low-oxalate recipes.
How is Oxalate Related to Kidney Stones?
Kidney stones can cause severe pain, blood in the urine, and a constant need or inability to urinate as the stone passes through to be excreted. According to the National Kidney Foundation, calcium oxalate stones are the most common type of kidney stones. These can occur when you have too much oxalate or too little fluid intake, causing the oxalate to bind to calcium and form crystals, which can stick together and form stones. Risk factors include family history, obesity, and certain medical conditions. Eating a diet too high in protein, salt, and sugar, and not drinking enough fluid can also increase the risk of forming kidney stones.
Should I Follow a Low-Oxalate Diet?
If you have had calcium oxalate kidney stones and your urinary oxalate level is high (as determined by a 24-hour urine test), you may benefit from a low-oxalate diet. Switching to a low oxalate diet may help reduce your risk of forming another stone.
The idea behind a low-oxalate diet is to lower your dietary intake of oxalate, making less oxalate available for absorption in your intestinal tract. This results in less oxalate in the urine and reduces the risk of a calcium oxalate kidney stone formation.
What Is a Low-Oxalate Diet?
There is no agreement on how much oxalate is acceptable on a low-oxalate diet, and it's difficult to determine the exact oxalate content of certain foods. But, the University of Chicago offers general guidance, suggesting to keep your oxalate intake below 100 mg per day, or ideally under 50 mg per day if possible.
If you've been advised to follow a low-oxalate diet, it's important to get familiar with oxalate-containing foods, especially options with high oxalate content.
Some very high-oxalate foods include:
- chocolate or cocoa
- spinach
- rhubarb
- beets
- wheat germ
- black teas (not green or herbal)
- some tree nuts (almonds, cashews, and hazelnuts are highest in oxalate)
- legumes (beans, peanuts, soybeans)
These foods may increase urinary oxalate levels. Generally, when you avoid these foods, the oxalate content of other foods will fall within the amount recommended for calcium oxalate stone formers.
For further guidance, refer to Table 1 (below). In general, do your best to avoid high-oxalate foods, limit moderate-oxalate foods to twice per day, and choose mostly low-oxalate foods to keep your oxalate intake in check.
Table 1. Foods to Choose and Avoid. Adapted from University of Pittsburgh Schools of the Health Sciences and the University of Chicago Update.
| Food Groups | Low-Oxalate Foods (Choose from These) |
Moderate-Oxalate Foods (Limit to Twice Daily) |
High-Oxalate Foods (Avoid These) |
|---|---|---|---|
| Beverages | Coffee, Sweetened Instant Iced Tea Water, Fruit Punch, Lemonade, Soda, Apple Juice, Orange Juice, Mango Juice, Pineapple Juice, Red/White Wine |
Prune Juice | Black Tea, Hot Chocolate, Chocolate Milk |
| Dairy & Substitutes | Butter and Margarine, Cream Cheese, Cheese, Coffee Creamer, Milk, Sour Cream, Whipped Topping, Yogurt | Soy milk, soy cheese, soy yogurt | |
| Fruits & Berries | Apples, Apricots, Bananas, Cantaloupe, Cherries, Grapes, Honeydew Melon, Lemon, Lime, Mango, Nectarines, Papaya, Peaches, Pears, Pineapple, Plantain, Plums, Raisins, Watermelon | Figs Canned Cherries Orange (no peel) |
Berries (Blackberries, Blueberries, Raspberries, Dewberries, Elderberries, Gooseberries) Tangerines, Dates, Kiwi, Grapefruit Dried Figs, Dried/Canned Pineapple, Dried Prunes Rhubarb |
| Vegetables | Bok Choy, Broccoli, Cabbage, Cauliflower, Corn, Cucumber, Green Pepper, Lettuce (Iceberg or Romaine), Mushrooms, Onions, Peas, Pickles, Sauerkraut, Yellow Zucchini, Squash | Asparagus, Artichokes, Cooked Carrots, Mixed Frozen Vegetables, Olives, String Beans, Tomatoes | Beets, Brussels Sprouts, Carrots, Celery, Okra, Parsnips, Potatoes, Rutabaga, Spinach, Turnips, Yams |
| Beans & Nuts | Hummus Flaxseeds |
Beans (Fava, Kidney, Navy, Red, Soy, and Refried Beans Nuts (Almonds, Cashews, Hazelnuts, Peanuts, Pecans, Pistachios, Mixed Nuts, Trail Mix, Walnuts Pumpkin Seeds, Sunflower Seeds |
|
| Breads & Cereals | Corn Bread, Oatmeal Bread, Oat Bran Muffins Oat Cereal, Corn Flake Cereal, Crisped Rice Cereal, Whole Grain Cereal |
Biscuits (Plain and Buttermilk), Bran Muffins, Cracked Wheat Bread, English Muffin (Regular, Multi-grain & Wheat), Rye Bread, Tortillas (Corn & Flour), Whole Oat Bread, Whole Wheat Bread | Blueberry Muffins, English Muffins (Whole Wheat) Bran and Raisin Bran Cereal, Frosted Wheat Cereal , High Fiber Cereal Wheat Germ |
| Pasta, Rice, & Grains | Macaroni & Cheese White Rice Oat Bran |
Couscous Cornmeal, Millet |
Brown Rice, Barley flour Bulgur, Corn Grits, Rice Bran, Wheat Bran |
| Meat, Meat Replacements, Poultry, & Seafood | Bacon, Beef, Chicken, Corn Beef, Eggs, Ham, Pork, Turkey, Venison, Wild Game Shellfish Fish (except sardines) |
Hot Dogs | Soy Burgers, Tofu |
| Desserts & Snacks | Custard, Popsicle, Oatmeal Cookies, Jello, Tapioca Pudding, Vanilla Pudding, Frozen Yogurt & Sherbert, Ice Cream Fig Bars, Rice Cakes, Saltines, Shredded Wheat Crackers, Graham Crackers, Whole Grain Crackers, Popcorn |
Pies Tortilla Corn Chips |
Chocolate, Chocolate Cake, Chocolate Chip Cookies, Brownies, Candy with Nuts, Chocolate Syrup, Fudge Sauce Potato Chips Pretzels |
| Other Foods | Chicken Noodle Soup | Beef Vegetable Soup | Lentil Soup, Miso Soup Stevia |
Practical Tips to Lower to Risk of Kidney Stone Formation
In addition to following a low-oxalate diet, here are some additional tips to help reduce your risk of kidney stones and optimize your urinary health:
- Drink 10-12 (8-oz) cups of fluid daily, half of which should be water. Remember to drink extra fluids in hot weather or during exercise. This will prevent dehydration and dilute the urine.
- Eat 2-3 servings of a dairy food daily; if you take calcium supplements, do so with food. Calcium will bind with oxalate in the stomach and intestine and limit absorption.
- Eat at least 5-9 servings of fruits and vegetables daily. Intake of potassium, fiber, magnesium, antioxidants, phytate and citrate, all naturally occurring in fruits and vegetables, may help keep kidney stones from forming.
- If you take vitamin C supplements, limit to no more than 500 mg daily. Vitamin C is converted to oxalate by the body.
- Limit your intake of meat, fish, and poultry. Your daily protein needs can usually be met with 2-3 servings a day of a protein source the size of a deck of cards. Choosing vegetable protein sources a few times per week can also help. High protein intake may increase the risk of kidney stone formation.
- Limit salt intake. Avoid using the salt shaker and go for fresh or frozen foods, rather than processed, convenience and fast foods. You can also follow the DASH diet if you choose.
Low-Oxalate Recipes
If you have had a kidney stone, you are at a higher risk for forming another one. Follow the tips and incorporate the recipes below to decrease your risk of forming another calcium oxalate kidney stone.
Low-Oxalate Coleslaw
Servings: 4-6
Author: Chef Matt
Ingredients:
- Salad Mix
- ½ head green cabbage, thinly sliced or shredded
- 8-10 radishes, thinly sliced
- ½ cup sliced green onions
- ½ cup thinly sliced red onions (optional)
Dressing:
- ½ cup of high-quality mayonnaise
- 2 Tablespoons grainy Dijon mustard
- 2 teaspoons honey
- 2 Tablespoons white wine vinegar
- Salt and pepper to taste
Directions:
- Whisk together the ingredients for the dressing and toss with the salad mix.
- Mix together well and season with salt and pepper to taste.
Low-Oxalate Chicken Jambalaya
Servings: 4-6
Author: Chef Matt
Chicken:
- 1 1/2 lbs chicken breast
- 1 teaspoon garlic salt
- 1 teaspoon chili powder
- 1 teaspoon Montreal steak spice
- Salt and pepper to taste
- 2 Tablespoons olive oil
Jambalaya:
- 2 cups white or wild rice
- 4 cups chicken stock
- 1 red pepper 1/4″ dice
- 1/4 white onion 1/4″ dice
- 1/2 cup green peas
- 1 teaspoon chipotle powder
- 1 teaspoon dried basil
- 1 teaspoon chili powder
- 1 cup canned chopped tomatoes
- 2 cups tomato sauce
- 2 tablespoons olive oil
- Salt and pepper to taste
Directions:
- Cook the rice according to the instructions on the box. Use the chicken stock in place of water.
- Heat a large sauté pan on high heat with 2 tbsp of olive oil.
- Season the chicken breasts well with the spices and sear in the pan until golden brown.
- Add the peppers, onions, and jambalaya spices to the pan and put into a 375-degree Fahrenheit oven. Cook until the chicken reaches an internal temperature of 165 degrees Fahrenheit.
- Take the chicken out of the pan and set aside. Keep warm.
- Make sure the spices are well cooked out and then add in the chopped tomatoes, tomato sauce, and peas and let come to a simmer.
- 7. Add in cooked rice and mix together well. Serve on plates with slices of chicken on top.
Low-Oxalate Protein Balls with Cherries and Bananas
Servings: 12 balls
Author: Chef Matt
Ingredients:
- 4 bananas, peeled and cut in half lengthwise
- 4 tbsp butter, room temperature, cut into small cubes
- 1 cup banana chips
- 4 rice cakes, white or whole wheat
- 1/2 cup raisins, sultana
- 3/4 cup canned cherries, chopped
- 1/2 tsp real vanilla extract
- 1/4 tsp ground cinnamon
- 1/4 tsp cayenne pepper
- 1 egg white
Directions:
- Heat up your oven to the broil setting. Sprinkle the cinnamon and cayenne on the banana halves and put on a baking tray. Broil for 5-7 minutes or until the bananas are well caramelized. Set aside to cool.
- Set the oven to 350 degrees. Blend the bananas with 2 tbsp. of the cubed butter in a food processor until smooth. Set aside.
- Blend the banana chips in the blender until the desired consistency has been achieved. Add in the rice cakes and pulse until chunky. Place on a baking tray and bake in the oven until crispy, about 10 minutes.
- Mix together the banana mixture, and the rice cake mixture with the rest of the ingredients. Mix well to incorporate all ingredients.
- Make 1-2 oz balls and bake in the oven for 10 minutes until the protein balls have set. Let cool and enjoy.
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