Oxalate or oxalic acid is a compound that body produces and naturally found in a spectrum of plant and animal food sources such as fruits, legumes, nuts and grains. It is not an essential nutrient for human beings, hence too much can lead to the development of kidney stones.
Minimal amounts of calcium and oxalates are present in the urinary tract does not cause any problems. However, in plants, oxalates aids to clear off excess calcium by binding with it, this is why many plant sources are abundant in oxalate.
As per the National Kidney Foundation, calcium oxalate stones are the most common type of kidney stones. These stones develop when there is excess oxalate or minimal fluid intake, causing the oxalate to bind to calcium and form crystal which stick together and form into stones.
How Does The Body Process Oxalate?
When you consume foods rich in oxalate, it travels via the gastrointestinal tract and eliminates out in the urine or stool. As it goes through the G.I tract, oxalate bind with calcium and it is excreted. However, excess oxalates get accumulated in the kidneys leading to kidney stones.
What Is A Low-Oxalate Diet?
A low-oxalate diet is a dietary plan that is low in oxalate, making very less oxalate available for absorption, this results in less oxalate in the urine and also reduces the risk of kidney stones formation. People with kidney stones are at a higher risk of forming stones again, the most common type of stone is made up of crystals that contain calcium and oxalate.
Causes of Oxalates Build-up
Food sources abundant in vitamin C can increase the body’s oxalate levels, as vitamin C is converted into oxalate. Research has shown that when the intake of vitamin C goes over 1000mg/day it elevates oxalate levels. Taking certain drugs like antibiotics and the history of digestive disorder can also increase the body’s oxalate levels. Gut healthy bacteria play a vital role in getting rid of oxalate, when the levels of good bacteria are low, higher volumes of oxalate are absorbed by the system.
How To Reduce Oxalate?
Drinking plenty of fluids can help clear kidney stones and also reduces the risk of stone formation. Hence adequate hydration is vital, choosing water over other drinks is desirable. Restricting intake of animal protein is also recommended, as a higher intake of meat products are known to cause stones. In addition, a low calcium diet also increases the amount of oxalate that gets to the kidneys, which increase the risk of kidney stones. In addition, reducing salt intake can also lower the risk of kidney stones, as a high-salt diet may lead to more calcium to be depleted in the urine.
Foods To Eat And Avoid In Low Oxalate Diet
The food sources are grouped into four categories based on their content of oxalates
Very High - more than 100 mg of oxalates per serving
High – 26-99 mg per serving
Moderate – 10-25 mg per serving
Low – 5-9 mg per serving
A low-oxalate diet emphasises a person to include foods from low to moderate category and avoid or limit foods and drinks that are high in oxalate.
Foods To Eat
There is a spectrum of food sources that are naturally low in oxalates and you can have them as part of a nutritious diet.
Here are some foods allowed to eat on a low oxalate diet
Fruits: Bananas, berries, cherries, strawberries, apples, apricots, lemons, peaches
Vegetables: Broccoli, cabbage, cauliflower, mushrooms, onions, peas, zucchini
Grains and starches: White rice, corn flour, oat bran
Proteins: Eggs, lean meat, fish, poultry
Dairy products: Yogurt, cheese, milk, butter
Beverages: Coffee, water, fruit juice
Herbs and spices: Cinnamon, black pepper, turmeric, cilantro, cumin, dill
Foods To Avoid
Some of the foods that are not allowed on a low oxalate diet include:
Fruits: Kiwis, dates, raspberries, oranges, tangerines
Vegetables: Spinach, potatoes, beets, turnips, yams, okra, carrots
Legumes: Navy beans, fava beans, kidney beans, refried beans
Nuts: Almonds, walnuts, pistachios, cashews
Seeds: Sunflower seeds, pumpkin seeds
Grains and starches: Brown rice, couscous, millet, bulgur, cornmeal
Beverages: Chocolate milk, hot chocolate, tea, tomato juice
Soy products: Tofu, soybeans, soy burgers
Remember soaking and then cooking food can remarkably reduce the oxalate content of most vegetables and legumes.