Link to first oxalate food chart fixed. Oxalates. How to know if you should avoid oxalate-containing foods.

Some health professionals tout oxalate dangers. Should you be concerned?

Oxalates. Your Questions Answered.

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So many food groups get a bad rap these days, such as oxalates, lectins, phytates, and FODMAPs. In this substack, I will discuss why oxalates can be a problem, how to identify those problems and address them so that you can eat some healthy oxalate-containing plant foods.

What Are Oxalates?

Oxalates, natural compounds found in plant foods (i.e., vegetables, fruits, nuts, grains), can impact the absorption of the plant's minerals because oxalic acid will bind to calcium in the digestive tract, block its absorption and increase calcium excretion (Gropper & Smith, 2018).

If an individual consumes a meal high in oxalates, the calcium absorbed is less than 5% (Gropper & Smith, 2018). Additionally, unabsorbed oxalates can chelate to magnesium and iron, reducing their bioavailability (Gropper & Smith).

This compound is considered an antinutrient because oxalates can bind to other nutrients. This suggests that oxalate-rich foods can have a negative effect on your body; however, this is not always the case.

Plants high in oxalates include spinach, rhubarb, Swiss chard, beets, celery, eggplant, okra, squash, strawberries, blackberries, pecans, peanuts, tea, cocoa, and other whole foods.  If one is trying to avoid foods high in oxalates, leafy greens that are safe to eat include kale, broccoli, mustard greens, turnip greens, and collard greens.

Several factors can affect the level of oxalates in a food, such as the growing season, weather conditions, and the plant variety. For instance, Avon spinach may have a higher oxalate content than Butterflay spinach. Cooking can reduce oxalate content in some foods. For instance, cooking spinach versus putting it into your green smoothie will have a lower oxalate content.

Why You May Have An Oxalate Intolerance

Gut Health and Oxalate Intolerance

Suppose you have increased intestinal permeability, gut dysbiosis, GI disorders such as IBS, yeast overgrowth (candida), or small intestinal bacterial overgrowth (SIBO). In that case, you may be susceptible to greater oxalate absorption than someone with a healthy gut who consumes the same amount of oxalates.

Beneficial gut bacteria help the gut get rid of oxalates. When there is dysbiosis, the oxalates can pass through the GI tract and contribute to common gut issues such as constipation, bloat, and diarrhea. If you have a healthy gut, very small amounts of consumed oxalates are absorbed into the bloodstream. In a healthy gut, roughly 1 to 2% of oxalates are absorbed, but it could be as high as 40 to 50% in an unhealthy gut.

A gut bacteria, called Oxalobacter formignes, breaks down oxalates and uses them for energy. Therefore, if you have this bacteria in your gut, it can prevent oxalates from binding to minerals and limit oxalate absorption. Studies indicate that people who have low levels of this bacteria strain in their gut are more prone to higher oxalate levels in the body.

The GI MAP via Diagnostic Solutions Laboratory is a helpful test for determining whether you have gut issues that need to be addressed. You can view the GI MAP test in my Lab Shop to see what it includes. You can also sign up for a free 15-minute phone consult to ask questions about the test.

It may be wise to remove high-oxalate foods while working on gut health, then slowly re-enter oxalate-rich foods and monitor your progress.

High-Dosing Vitamin C

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Vitamin C-rich foods can increase the body’s oxalate levels since oxalates are produced as the end product of vitamin C metabolism. If you consume more than 1 gram of vitamin C daily via food and supplementation, reevaluate the dosage and decrease the amount to see if this helps to reduce oxalate sensitivity. High C dosing can increase the number of oxalates in the urine and increase the risk of kidney stone formation.

If you take a vitamin C supplement, keep it at 500 mg if you have oxalate issues. Some people require higher doses, but most only need higher doses in the short term, such as during a viral infection. If you eat a whole-food diet, you probably do not need to supplement with vitamin C regularly.

Antibiotics

Taking antibiotics regularly, such as twice or more in a year, can increase the body’s oxalate levels.

I am not opposed to taking an antibiotic when it is required, but often, doctors prescribe antibiotics when they are not needed. For instance, years ago, my son had a very bad sore throat, and when the PA examined him, she concluded he had strep throat. I asked for a strep test, and she rolled her eyes at me but complied. I was glad I did ask because the result was negative for strep, and we treated the sore throat like any other minor viral infection.

If you have taken an antibiotic in the past year before your symptoms began, I again suggest the GI MAP test to determine if gut health warrants attention.

Diets High in Oxalates

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A serving of 10 mg. or more of oxalates is considered a high oxalate food and should be avoided while addressing the underlying root causes.

Diets that tend to be high in oxalate-rich foods include vegan, vegetarian, raw food, paleo, ketogenic, and low-carb diets.

This food chart helps indicate which foods are negative for oxalates or have very low, low, moderate, high, or very high oxalate content. For instance, beef, fish, and chicken contain no oxalates. Acorn squash, avocados, and butter are very low oxalate-containing foods. Apples, asparagus, and olive oil are low oxalate-containing foods. Artichokes, banana, and steamed green cabbage are moderate oxalate-containing foods. Some foods high in oxalates include kidney beans, oranges, and tomato paste. Lastly, high oxalate-containing foods include raw carrots, cashews, and celery.

However, the chart I provided does not indicate the mg. content of the foods. For example, three ounces of cashews, a very high-oxalate-rich food, contains 260 mg of oxalates. This chart provides the oxalate amounts.

Some foods fall into different oxalate level categories depending on whether they are consumed raw or cooked.

Autism and Oxalates

Some parents follow the SCD (specific carbohydrate diet) for their autistic children, which is high in oxalates. The SCD may not result in improvements for the child because of the oxalates. This is because many children with autism will need to address gut health first and remove oxalates while addressing underlying gut issues.

Add Calcium-Rich Foods to a High Oxalate Meal

A different approach to take instead of reducing the oxalates in the diet may be to increase the amount of calcium. This approach may be helpful if you consume a calcium-rich food at the same meal as a high oxalate-containing food. The calcium and oxalates will bind together before they reach the kidneys, making it less likely that a kidney stone will form.

Calcium-rich foods to add in (organic) include dairy, broccoli, watercress, kale, kidney beans, garbanzo beans, navy beans, sardines with bones (I checked, and Wild Planet sardines do contain the bones), and salmon (not farmed). Some of these calcium-rich foods, such as navy beans ( 76 mg of oxalates per 1/2 cup), may also contain oxalates.

Kidney Stones and How to Prevent Them From Developing

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Oxalates can bind to minerals such as calcium in the kidneys to form calcium oxalate kidney stones, the most common type of kidney stone. Most people can remove these compounds in the urine, but accumulation can occur for others, leading to stones.

Even if you address the root causes mentioned in this substack, some people are just more prone to stones than others, and in this case, a low-oxalate diet may be beneficial. However, staying hydrated with water to dilute urine may be a better option to prevent oxalate collection in the kidneys.

Kidney stones may not be caused by oxalates but by something else, such as a high-protein diet, dehydration, or a diet high in processed sodium.

Most people require .8 to 1.2 protein grams per kg of body mass (not extra fat stored on the body). There is no reason for most individuals to overdo protein intake, especially if you are prone to kidney stones.

A high-salt diet may cause more calcium to be lost in the urine. The more calcium and oxalate in the kidneys, the greater the kidney stone risk. If you consume a whole foods diet, sodium should not be an issue.

Deli meats, sausages, hot dogs, canned products, dry soup mixes, packaged snack foods, and a host of other products are concerning high sodium-containing processed foods. You may not need to keep track of salt intake; instead, you should replace processed sodium-containing foods such as some fastfood meals.

Here is a link to 25 of the saltiest fast-food meals. For reference, one teaspoon of salt equals 2,300 mg of sodium. If you use the salt shaker on whole foods, your salt intake is likely acceptable or even low. The majority of sodium concerns are related to a highly processed diet.

Staying hydrated can help clear stones and prevent them from forming. Spread fluid intake throughout the day and choose filtered water. Some research suggests that lemon water may reduce oxalate stone formation and will inhibit stone formation and can help break up small stones just beginning to form.

What is Oxalate Dumping?

The term oxalate dumping applies when you quickly remove oxalate-rich foods from the diet. This can result in cramps, dizziness, pain, and fatigue. A better option is to slowly reduce the oxalate content in the diet or add more calcium and stay hydrated with filtered water or lemon water.

Testing

In addition to the GI MAP, which identifies potential gut issues, the Organic Acid test (OAT) measures oxalate levels. The OAT is a urine test that examines levels of organic compounds in the urine. These compounds are produced in the body as part of many vital biochemical pathways. The oxalate metabolites include glyceric acid, glycolic acid, and oxalic acid. Ideally, all three should be low.

If you want to order this test, more details can be found at https://mosaicdx.com/test/organic-acids-test/. If you want me to order and review the test results, sign up for a free 15-minute phone consult, and we will order it then. You can also visit my Lab Shop and order the OAT there.

Bottom Line

Most people do not need to follow a low-oxalate diet unless they are prone to kidney stones even after addressing underlying root causes such as gut dysfunction. A green smoothie or a glass of fresh vegetable juice for most people is not an issue when consumed in moderation.

Symptoms of an oxalate issue include acid reflux, heartburn, bloating, constipation, diarehia, gas or kidney stones.

However, these are also symptoms of many other health-related issues as well. To determine if oxalates pose an issue for you, test or reduce the oxalate content in the diet for several months and then reintroduce these foods back into the diet or use some of the strategies mentioned in this post such as increasing foods rich in calcium and hydrating with filtered lemon water and monitor your symptoms.

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Additional Source

Gropper, S., & Smith, J. (2018). Chapter 11. Major Minerals. In Advanced nutrition and human metabolism (7th ed.). Cengage Learning.

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My goal is to get true health information to as many people as possible so that you can take charge of your own body instead of relying on the system to take care of it for you.