Clearing Up the Confusion Within Oxalate Lists

So you’ve finally got your hands on a reliable oxalate list — let’s clear up some of the confusion that comes from trying to decipher them.

In order to come in under that 50, 100 or however many mg of oxalate per day you decide is your goal, you'll need to know about how much oxalate is in the food that you eat or which foods are considered low, medium, and high.

How Much Oxalate is Low, Medium or High?

In general, low oxalate foods will have 5mg of oxalate in a serving, between 5-15mg is considered medium, and anything more than 15mg is going to be high. The key phrases here are in general and in a serving. You might have noticed that one list will refer to a food as low oxalate while another refers to it as medium, or one will say a food is medium, and other will say that the same food is high.

One of the reasons for this is that there's really no standard for the low, medium and high categories — they can be different depending on the resource and what range they've created for their specific list. One list may have 5-10mg as the medium category, 10-15mg as high and anything more than 15mg as very high.

In all my posts, I’ll use <5mg as low, 5-15mg as medium, and more than 15mg per serving as high.

Check Your Portion Sizes

One of the other main reasons for discrepancies between foods being called low, medium or high oxalate is the portion size that they're referring to. For example, chickpeas have about 4mg of oxalate in one half of a cup. So if you're referring to a half of cup of chickpeas, then you would say chickpeas are low oxalate. But if you're referring to a cup, then that would be 8mg total, and you might say that they are medium oxalate.

Another example would be for the something like oregano, which has about 8mg of oxalate in one teaspoon. If you're referring to a teaspoon, because it's between 5-15mg, you could say it's a medium oxalate food. But many oxalate lists have spices listed in tablespoon portion sizes. Since there's three teaspoons in a tablespoon, that would put a tablespoon of oregano at about 24mg and you might call it high oxalate.

Portion size is probably the most important factor to consider when deciding which foods you want to call low, medium or high oxalate, especially when it comes to spices. If you're trying to maintain a balance between a low oxalate diet and still have a nice variety of flavors in the meals that you're eating, you’ll want to pay special attention to this, so you don’t end up excluding foods that you don’t need to.

If you're using a tablespoon of oregano in every meal you have, then that's going to add up pretty quickly and it might make it difficult to stay within your target range of oxalates per day. But in the amounts you would probably actually eat, it’s not really an issue.

If a recipe calls for a tablespoon of oregano, that doesn’t necessarily make it a high oxalate recipe either — the recipe might make 6 or 8 servings of the dish, in which case you wouldn’t be getting anything near that full tablespoon.

How Was the Item Tested for Oxalate Content?

Another thing that really makes a difference in the amount of oxalate each food entry on a list might have is the method that was used to test that food or the date that it was tested. There are a few different ways to test the levels of oxalate in different foods. Without getting into all the details, just know that the methods have improved over the last 20 years. So depending on when certain foods were tested, the levels might be different.

When in doubt, look for the most up to date test results. This is one of the reasons why the TLO spreadsheet can be very helpful. They list the date that each item was tested, and if they don't have the date there, then they have a source for where they got the information, which will have the date that the testing was done. They also send out new foods, or old foods to be tested again, a couple times per year.

Why the Same Food Might be Listed More Than Once

Another source of confusion comes from that fact that some foods are listed more than one time within a list. More than one entry is usually a good thing though, because it’s a sign of a thorough list.

The first thing to consider here is the specific type or species of food, like the avocados and apples I talked about in my previous post. But you'll also notice differences between red and green peppers, red and yellow onions, or different types of tomatoes and avocados. Another interesting difference that can come up is the ripeness of some fruits.

How Ripe is the Food You're Eating?

Avocados are a perfect example of something that changes oxalate levels a lot depending on the portion size and the species, but also how ripe it is when you eat it.

Avocados are a food that you'll usually see listed as high-oxalate. Most of the time avocados are high oxalate, but Hass avocados are lower than other varieties, and the riper they are, the lower they are in oxalate. Half a cup of a ripe, Hass avocado has less than 5mg of oxalate in it, so avocados are something that I still include in my diet.

Check Which Part of the Plant You're Eating

A few other things that can make a difference are the parts of the plant that a food is taken from, and the part of the grain or seed. For example, black pepper is usually considered a high oxalate food (even though it's similar to oregano in that a teaspoon is medium oxalate) and white pepper is low oxalate. White and black pepper are both made from the same plant and actually the same seed, but white pepper is made from the inner part of the seed and black pepper is from the outer shell portion of the seed.

The same is true for a food like sesame seeds, which can be one of the highest oxalate foods — they become much lower in oxalate if the shell is removed from them, which they are in most cases.

Are Your Grains Whole or Not?

Grains like rice need to be considered in the same way. Brown rice and white rice come from the same grain, but brown rice is the whole grain and white rice is made from only one of the three parts of the grain, so they differ in oxalate levels as well. We’ll talk more about rice and other in a bit.

Another thing that's important when it comes to discrepancies in classification is whether or not something is on the borderline between two of the low, medium, or high categories. If something has 4.9mg of oxalate per serving, then it will be listed as low. And if it is 5.1, then it will be listed as medium with other foods that have up to 14.9mg.

Small nuances like this can make a big difference because you might be limiting yourself more than you have to. Towards the beginning of adopting this diet, I was missing out on some important vitamins, minerals and fiber by only eating lower oxalate white rice, because everything other type of rice was listed as medium or high oxalate.

When I took a closer look at the TLO spreadsheet, I found that there was a whole grain red rice that was just as healthy, if not more healthy than some of the brown rice and definitely more healthy than the white rices — and it didn't have much more oxalate than the white rice I was eating, so I made the choice to include it in my diet.

It’s Lotus Foods Red Rice, which only has 5.9mg of oxalate in one half a cup of cooked rice. That puts it in the medium range technically, but just over that 5mg/serving borderline.

Looking for Low Oxalate Recipes?

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More Reading on Low Oxalate Diets

• What Kind of Bread Can You Eat on a Low Oxalate Diet?
• How Boiling, Steaming, and Other Cooking Methods Affect Oxalate Content
• Low Oxalate Substitutions and Sticking to the Diet