Our Most Frequently Asked Questions

Oxalate and Oxalic acid are terms used interchangeably to describe a naturally occurring compound found in plants and your body. It is not something you can see, touch, taste or even smell yet they are everywhere… including the grass you walk on. They are not needed by the human body and considered an anti-nutrient as they provide no nutritional value and bind to vitamins and minerals of the foods you do eat to reduce the nutritional amounts that your body absorbs. In short, they take away and destroy essential vitamins and minerals.

Oxalates are found in foods, animals, and in your body. In plants, they are part of their defense system against pests & predators and to promote seed germination by storing calcium for offspring. In foods, oxalates are naturally present and found in plants and their by-products including fruits, vegetables, seeds, nuts, grains and even cocoa. It can be found in meats from animals that were grass fed or processed, and even fish whose diet is only phytoplankton. Some foods contain miniscule amounts while others contain high amounts. It is also found inside your body produced within your liver from amino acids, red blood cells etc. If you were to consume no oxalate, it would still be present in your urine due to your body’s metabolism. In other words, oxalates can be hard to avoid but you can limit the amount you ingest.

All components that make up the parts of a plant contain oxalates (oxalic acid). Each plant brings it own health benefits to your plate as well as oxalate content. Most people consume the bulk of their dietary oxalate from the following:

Leaves or leafy greens: Salads, pesto, stir fry or smoothies with lettuce, kale, spinach, basil, beet greens etc. as the primary ingredient.

Root plants: This includes foods from your popular tubers and bulbs such as French fries and baked potatoes, potato chips, carrot sticks, onion rings, candied yams, water chestnuts & bamboo shoots in your stir fry, and roasted Jerusalem artichokes to name a few.

Stems/stalks: Yes, that celery stick you are munching on, and those asparagus spears on eggs benedict (my fave!) and rhubarb are all plant stalks.

Flowers: In addition to the familiar rose or marigold that looks pretty in spring, this category also includes a wide variety of vegetables (squash, pumpkin, tomatoes and eggplants) and popular fruits such as berries, apples, oranges, plums and bananas to name a few. They are consumed fresh, cooked, or within condiments, sauces, marinades, yogurt etc.

Nuts & Seeds: Mostly associated with raw nuts from trees (almonds, pecans, pistachios, walnuts, macadamia etc.) they are more commonly consumed in nut butters & oils, spreads, granola, energy bars, breads, flours and soups to name a few.

As you can see from the above, oxalates are pretty much found in all plant-based foods.

Calcium oxalate stones are a type of kidney stone which accounts for 80% of kidney stones found in patients.The stone which starts out about the size of a grain of sand is formed when your urine becomes too concentrated with high levels of oxalic acid. It is this high concentration of oxalate (oxalic acid) that alters your urine’s pH and over time will bind with calcium salts to form crystals. When these crystals stick together they harden into tiny stones. The stones can take weeks or even months to develop. The size and number can vary from a couple of large stones to many small stones depending on the amount of crystalline material present.

Calcium oxalate stones are the most common type of kidney stone. Calcium oxalate and calcium phosphate stones account for 80% of kidney stones found in patients. This app is focused on Calcium Oxalate kidney stones.

There are 4 different types of kidney stones:

• Calcium stones You can have either Calcium oxalate stones or Calcium phosphate stones.

• Uric acid (formed from monosodium urate crystals) These are the second most common stone found, possibly caused by a high protein diet where intake of "purines" (instead of oxalates) may need to be restricted.

•Stuvite (formed from magnesium, ammonium, and phosphate) Found mostly in women and associated with urinary track infection (UTI).

• Cystine This type of stone accounts for less than 1% of kidney stones found making them extremely rare. These stones are generally found in individuals with a hereditary condition known as "cystinuria”.

Do not assume you have calcium oxalate kidney stones. Have your stone analyzed to identify the specific type. Each stone type has a different chemical composition which in turn will help your physician focus on the cause and the appropriate dietary approach to reduce the risk of recurrence. In other words, a low oxalate diet may not benefit someone with uric acid stones. Check with your healthcare professional.

Your healthcare professional may be able to advise you based on the results of a urine test or blood test. If a stone is available, a lab analysis can be performed to determine the composition.

A common misconception is calcium oxalate stones come from too much calcium. If you think about it, your body has and needs calcium to maintain your bones, teeth, tissues, etc. Eating foods high in calcium or pairing calcium rich foods with moderate or high oxalate foods will actually reduce the likelihood of calcium oxalate stones forming due to the way it binds to oxalate in the stomach and intestines. Unless you are lactose intolerant, the recommendation is not to stop eating or cutting back on calcium, but to maintain your calcium intake (preferably without using calcium supplements).

A low oxalate diet combined with adding more fluids daily has been proven to lower the risk of forming oxalate kidney stones. Does it guarantee you’ll never get a kidney stone again? Unfortunately, there are never any guarantees.

Some people are more susceptible to developing kidney stones. Many go through life not experiencing the passing of a stone, while others live with it on a continuous basis. There is not one single cause responsible, but a combination of factors that increase your risk.

• Family history/hereditary: It’s in your genes and passed down to you from earlier generations. Nothing you can do about that. If you ask, you’ll learn you aren’t the first in your family to have kidney stones.

• Dehydration: Simply put, you don’t drink enough water to dilute minerals in your urine. Your fluid intake is too low. You can judge your hydration level by the color of your urine. Dark/deep yellow is a sign that you don’t drink enough water and your urine is concentrated. Light/pale yellow or clear are a healthy sign of hydration making it harder for stones to form.

• Diet: Yes, food choices and diets are a contributing factor. A diet rich in high oxalate foods, animal proteins, sugary drinks and salty foods increases the amount of calcium in your kidneys which in turn increases your risk for kidney stones.

• Obesity: Your kidneys do not increase in size to support your extra weight. When you are overweight, your kidneys are forced to work harder to support the extra body mass. That extra body mass or high body mass index (BMI) makes your kidneys less effective which increases your risk for stones to form as well as diabetes and heart disease.

• Medical conditions: You are one of those individuals with a disease or condition (i.e. Diabetes, Dent or Crohn’s disease, surgery...) where your body is sensitive to oxalates that unfortunately makes you susceptible to kidney stones.

• Geography: Where you live may also increase the risk of developing kidney stones. According to a population survey by the National Institute of Health, if you reside in the Southeastern part of the United States (known as the ”Stone Belt” by urologists) you are 50% more likely to form kidney stones than the rest of the country. Continuous exposure to the heat and sun’s rays make you more susceptible to water loss (sweat) and dehydration. The typical Southern American diet and its comfort foods is also a major contributor. Southern foods are rich in fried foods and added fats (fried chicken, fried catfish, fried okra, hushpuppies, biscuits & gravy, pork green beans etc), sugary drinks (sweet tea, sodas) and high oxalate foods (grits, okra, turnip greens, collard greens) that can lead to heart disease, high cholesterol, high blood pressure, obesity, diabetes and kidney stones.

No. Once a stone is formed it will either pass or it will grow. Water will not ”dissolve” an existing stone. Water only aids in passing existing stones and preventing new ones from forming.

Yes and no. With the exception of blanching or boiling (and removing the liquid), the amount of oxalate removed by steaming, pressure cooking, slow cooking, blanching, frying, grilling and baking is not significant to reduce the amount of oxalate to impact your daily limit. Additionally, the process of cooking or overcooking to remove oxalate may actually result in the loss of other beneficial vitamins and minerals at the same time, as well as giving your food a less desirable taste. A high oxalate food (for example, spinach) will remain high oxalate even after boiling and removing liquids. Your best option is to avoid oxalate dense foods altogether or pair with a calcium rich food for the occasional treat.

Depending on your individual situation, your healthcare professional will limit the amount of oxalates you consume. For most stone formers the daily limit is 40-50 mg per day. To maintain your daily goal you will need to make certain dietary adjustments to avoid high oxalate foods and manage your intake of others to stay within your limit..

A ketogenic diet is basically a low carbohydrate, high-fat, low sugar and moderate protein diet that forces the body to rely on its fat for fuel instead of intake of carbohydrates and sugar. There is no scientific evidence to suggest a Ketogenic diet will “give you” kidney stones. It will not increase or decrease your risk for kidney stones. It may however, exacerbate an untreated condition if you are predisposed to kidney stones, have oxalate hyperabsorption or do not drink enough water to stay hydrated.

There are many factors that can affect your daily oxalate limit. The average person consumes upwards of 200-300 mg daily. Your physician or health care professional will recommend the appropriate amount for your individual situation. Typically, the amount for calcium oxalate stone formers or individuals at high-risk is 40-50 mg daily.

The current database contains a little over 1100 foods.

Yes. As marijuana becomes main stream with more states legalizing for either medical or recreational use, it was only a matter of time before this question would become a popular one. Oxalate crystals are found throughout leafy green plants therefore, all parts of the cannabis plant (leaves, flowers, buds, seeds, hash, stems) contain oxalic acid crystals. Any bi-products including edibles derived from any part of the plant (cannagidiol “CBD” oil, wax, smoothies & other beverages/foods, gummies, the popular “brownie” etc.) also contain oxalic acid crystals. How much oxalate? As to specific amounts, I have found no scientific evidence to indicate cannabis has been tested for oxalic acid concentrations at this time.