I have had more than one client ask me lately whether they need to worry about oxalates in their food.
It is easy to see why the question comes up. Spinach and almonds keep getting treated like suspects online, held up like evidence of something gone wrong. And I understand why it lands. When you have been tired for a long time and nothing has worked, the idea that one hidden thing in your food is behind all of it is an enormously appealing idea.
So let us slow it down and look at this properly, because there are people for whom oxalates matter a great deal, and there are far more people being told to worry about something that is doing them no harm at all.
The quick version
Oxalates are natural compounds found in plenty of very good plant foods.
Most people handle them without any trouble whatsoever.
A specific group of people does need to pay real attention.
How you cook and what you pair food with often matters more than removing it.
What oxalates actually are
Oxalates, also called oxalic acid, are compounds that plants make on their own. They are not an additive, they are not contamination, and they are not new. They have been in our food since food existed.
Here is the friendliest way I can explain what they do. Oxalate is a bit like a magnet for minerals. When it meets calcium, it grabs on and the two form a pair.
Most of the time that is a perfectly good thing. When oxalate meets calcium down in your digestive tract, they link arms, the pair is too big to be absorbed, and it simply leaves the body. Nothing dramatic happens. That is the system working exactly as designed.
The question is only ever about what happens when more oxalate gets absorbed than your body is set up to pass along. And for most people, that is not what is happening.
Where oxalates show up on your plate
You are going to notice something about this list.
Spinach: the highest of the common ones by a wide margin
Rhubarb: very high, though most of us eat it seasonally
Beets and beet greens: both the root and the tops
Almonds: and almond flour and almond milk, which add up fast
Sweet potatoes: higher than white potatoes
Dark chocolate: cocoa is naturally high
Look at that list again. Spinach. Beets. Sweet potatoes. Almonds. Dark chocolate. These are not junk foods hiding in a corner of the grocery store. These are the exact foods most of us have been told to eat more of, and for very good reason. They bring fiber, potassium, magnesium, folate, vitamin A, vitamin K and antioxidants to the table.
That is why I will not tell you these foods are bad. They are not bad. They are wonderful foods that a small number of people need to approach differently.
Healthy food is not one size fits all.
Why most people handle them just fine
Your body has more than one way of dealing with oxalate, and I think this is genuinely lovely.
First, the calcium pairing I mentioned. Eat something calcium-rich alongside an oxalate-rich food and much of that oxalate gets bound up in your gut and escorted out before it ever gets absorbed.
Second, you have help. Certain bacteria living in your gut break oxalate down as part of their own daily business. You have a whole microscopic crew working on this for you, free of charge, and you never think about it once.
Third, your kidneys are built to filter and clear what does get absorbed, and staying well hydrated makes that job easier.
Three separate systems, all working quietly. For most healthy people with a varied diet, that is the end of the story. The spinach in your omelet is not doing anything to you.
Who tends to pay attention
Now, there absolutely are people for whom this is real and worth taking seriously. Generally that includes:
People with a history of calcium oxalate kidney stones. This is the big one, and it is where nearly all of the good research lives. If you have had a stone, your provider may well have already talked with you about this.
People with conditions affecting fat absorption. Things like Crohn's disease, celiac disease, chronic pancreatitis, or a history of bariatric surgery can change how much oxalate gets absorbed, sometimes considerably.
People with a rare inherited condition that causes the body to produce far too much oxalate on its own. This one is uncommon and is managed with a specialist.
People who have taken one of these foods to an extreme. Three cups of raw spinach in a smoothie every single morning, an almond-flour-based way of eating, a daily beet drink. Quantity and frequency change the math.
And here is the part I really want you to hear. Notice that every category on that list is defined by something about the person, not by something about the spinach.
A daily habit deserves a second look
This is the bigger idea underneath the whole conversation, and honestly it applies to far more than oxalates.
We are quick to scrutinize the occasional thing. The birthday cake. The restaurant meal. The glass of wine on a Friday. Those get examined closely and sometimes apologized for.
Meanwhile the thing you do every single morning without thinking gets a complete pass, simply because it is labeled healthy. The green smoothie. The handful of almonds at three in the afternoon. The overnight oats. Those became a habit, and habits stop getting questioned.
But a daily habit deserves the same scrutiny as an occasional one. More, really, because you are doing it three hundred and sixty five times a year. The rhubarb pie you have in June is not the thing shaping your health. The thing you have every day is.
I am not saying stop. I am saying look at it, because you probably never have. And most of the time the answer is not removal, it is variety. Rotate your greens. Let spinach be one of four or five, not the only one. Variety is the oldest nutrition advice there is and it quietly solves this problem before it starts.
The practical side of lowering them
If you and your provider decide this is worth working on for you, here is the good news. There is a lot of room between eating something every day and never eating it again.
Cook them differently
This is the one most people do not know, and it is my favorite. Boiling meaningfully reduces the oxalate content of vegetables, because oxalate dissolves into the cooking water. Research comparing cooking methods found boiling to be considerably more effective than steaming, and steaming more effective than baking.
The practical version: boil, then drain and discard the water. Do not use it as a broth base, because that is where everything you just removed is sitting. Sauteed spinach that cooked down in its own liquid keeps what it started with.
Pair with calcium-rich food
Remember the magnet. Give oxalate some calcium to link up with at the same meal and much of it never gets absorbed. This means eating them together, in the same sitting, not calcium at breakfast and spinach at dinner.
Spinach with feta. Sweet potatoes with a dollop of plain yogurt. Almonds with a piece of cheese. Dark chocolate after a meal that had dairy in it. These are not sacrifices, they are just good food. Sardines, canned salmon with the bones, tahini and leafy greens like kale and bok choy bring calcium too if dairy is not your thing.
Drink your water
Hydration is the least glamorous item on every list I ever write, and it is on every list for a reason. Fluid dilutes what your kidneys are filtering and helps things move along. If somebody is thinking about oxalates seriously, water is usually the very first thing their provider brings up.
Go gradually
Please do not overhaul everything in one weekend. Dropping oxalates abruptly and dramatically is not the gentle approach it sounds like, and providers who work in this area generally favor easing into it.
Gradual also means you can actually tell what is working. Change six things at once and you will never know which one mattered. Change one, give it a few weeks, pay attention. That is how you learn your own body instead of borrowing someone else's answer.
Two things worth mentioning to your provider. If you take warfarin or another blood thinner, changing how many leafy greens you eat changes your vitamin K intake, and that can affect how your medication works. Keep your provider in the loop before you shift your greens around. And if you add a calcium supplement, timing matters: calcium can interfere with the absorption of thyroid medication and certain antibiotics. None of that is a reason to skip calcium, it is simply a reason to ask about spacing.
Questions worth bringing to your doctor
Before you take anything off your plate, take these in. Removing food is a real decision and it deserves a real conversation.
I eat spinach, almonds or beets most days. Given my history, is that worth a closer look for me?
Before I take a whole group of foods off my plate, is there any reason to think oxalates are actually part of my picture?
If I do lower them, what am I giving up nutritionally, and how would you want me to replace it?
I take a daily vitamin C. Does the amount matter for someone in my situation?
I am planning to change my greens and add more calcium-rich food. Does either of those affect the medications I take, and how much fluid should I be aiming for?
My take
I love that women are paying closer attention to their food. I genuinely do. That instinct is right, and it is how almost everybody I work with got started.
What I do not love is watching someone eliminate six nutritious foods because of a video, get no better, and end up with a smaller diet and less confidence than when they started. Every food you remove takes its nutrients with it, and I have seen that trade go badly more than once.
So my honest answer on oxalates is this. If you have a history that puts you in one of those groups, take it seriously and work with your provider, because for you this genuinely matters. If you do not, eat the spinach. Boil it sometimes, put some feta on it, rotate in some kale and chard and romaine, drink your water, and go enjoy your life.
And it is October, which means roasted vegetables and soup and sweet potatoes are about to be everywhere. Fall is my favorite season by a mile, and I would hate for anyone to spend it afraid of a vegetable.
Want help deciding what actually belongs on your plate? My free Food Quality Guide walks through how to judge what you are buying, and my Healthy Pantry Swap Guide gives you the easy upgrades. Both are waiting in my free resource library.
This post is for education only and is not medical advice. I am a Certified Holistic Health Coach. I do not diagnose, treat, prescribe for or cure any medical condition, and nothing here is intended to do so. Please talk with your healthcare provider before starting any supplement or making significant changes to your diet, especially if you are pregnant, nursing, taking medication, or managing a health condition.
Where this comes from
National Institute of Diabetes and Digestive and Kidney Diseases (NIH): Eating, Diet, and Nutrition for Kidney Stones
Cleveland Clinic: Hyperoxaluria, and Oxalate-Controlled Diet patient resources
Mayo Clinic: Kidney stones, overview and prevention
National Kidney Foundation: patient guidance on oxalate, calcium and kidney stone prevention
Chai W and Liebman M, Journal of Agricultural and Food Chemistry, 2005: "Effect of Different Cooking Methods on Vegetable Oxalate Content"
Mitchell T and colleagues, American Journal of Physiology: Renal Physiology, 2019: "Dietary oxalate and kidney stone formation"
National Institutes of Health, Office of Dietary Supplements: fact sheets on Calcium and Vitamin C