In this episode of Functional Medicine Research, I interview Sally Norton in a discussion about how oxalates affect your thyroid and your health. We covered what oxalates are and how they can damage the body. We also discussed how oxalates affect gut health, liver health, thyroid health as well as all the symptoms and associated conditions connected to oxalates.
If you're really struggling to get well, but your diet appears to be healthy, oxalates may be the missing link.
Full Transcript on Oxalates and Thyroid Health
Dr. Hedberg: Well, welcome everyone to "Functional Medicine Research." I'm Dr. Hedberg, and I'm really looking forward to my conversation today with Sally Norton. Sally is a consultant writer, educator, and speaker with over 30 years in the health promotion and wellness field. Sally specializes in helping people improve their health with an oxalate-avoiding diet. Sally holds a nutrition degree from Cornell University and a Master's of Public Health degree from the University of North Carolina at Chapel Hill. She worked in the field of medical education at UNC Medical Schools Program on Integrative Medicine and as a research grant writer and research administrator at the Virginia Commonwealth University School of Medicine. Despite a healthy lifestyle, she struggled for over 30 years with seemingly unanswerable health challenges, including chronic pain and fatigue. When she finally discovered the cause and turned her health around, she committed to teaching and reaching out to others stuck in similar frustrating situations. Sally, welcome to the show.
Sally: Thank you. It's great to be here.
Dr. Hedberg: Yeah, I'm looking forward to this and we were kind of discussing this early on. Oxalates is something that I've always kept my eye on for the last 17 years and I was really looking forward to this conversation. So why don't we lay a little bit of bedrock for the listeners? And if you could just talk about what are oxalates, and do we know why plants actually have oxalates?
Sally: Yes. Plants are a major producer of oxalate and obviously, it's also ubiquitous in nature itself. Soil is loaded with it. Even apparently sea spray produces some oxalate and polluted air produces oxalates, so, in really heavily polluted cities, the air has got oxalate in it too. So oxalate is this really minuscule molecule that its parent compound is called oxalic acid. And acids ionize and become charged particles because they drop off the acidic protein and so they become these negatively charged ions that attract positively charged things and oxalates can have a one negative or two negative. It is a tiny, tiny little compound. It has four oxygens, which is a heavy load of oxygen on just two little carbon molecules. So it's very oxygen-heavy, which is probably partly why it's such a pro-oxidant molecule, you know. Oxidation is very bad for tissues, membranes, mitochondria, and it is a great mitochondrial poison, membrane destroyer, and troublemaker. And it's not just the oxygen, though. It's much more about this reactivity that the charge creates where it bonds with minerals and becomes salts. And so, salt is a chemical term for things that can dissolve, but when it...because it can have two negative charges, it will also hook up with minerals that won't dissolve well. So calcium, for example, is a two positive charge mineral. With that double-positive and double-negative marriage between the two, you create an insoluble oxalate, which is the backbone of oxalate you see in nature because calcium is everywhere in soils and in nature, and plants are having to manage their calcium. And one of the ways they do that...because too much calcium can be toxic to the plant. So one of the ways they do that is they make oxalic acid. Often they make vitamin C first, very similar compounds, and vitamin C naturally degrades just hanging around into oxalic acid and oxalates.
So plants will create vitamin C and they'll create oxalic acid so they can manage their calcium and store it away like a pantry. And in a siege, you need to store that calcium because calcium can be an enzyme co-factor and promote the germination process. So you store it, you deep-six it in these crystals in your seeds, and then when you germinate as a seed, you liberate off the oxalic acid in the calcium and you get your enzymes going. And in the meantime, those lovely crystals of calcium oxalate in the seed coat protects the seed from degeneration and from predators, and from deterioration, so it helps preserve the seed. But the oxalate has many other uses for plants, and plants deliberately construct special shapes of crystals.
They lay out this kind of protein matrix and then the crystals nucleate and create these crazy shapes, including a double-pointed toothpick, super fine invisible toothpicks made in bundles of like 200 or more. And the plants literally use them as poison arrows to disturb the mucous membranes of predators and so on and it can kill off caterpillars and bugs and can be damaging to be eating a lot of them in certain foods. Or they haven't actually studied, like, what shape crystals in food plants that much. So we know of a handful. The kiwi is notoriously full of these tooth-picky [inaudible 00:05:05] crystals, for example. So, they use them for self-defense in a direct kind of...I say that plants invented warfare because they have these poisoned arrows and they put on these arrows, proteases and soluble oxalate-related and things that are quite toxic to cells, and if you injure the mucous membrane, then you can enter the intercellular space and potentially enter the circulation and be quite dangerous and hazardous to the victim. But, like, trees will put out hundreds of pounds of oxalate crystals in these cube blocks in their bark, which helps make the bark inedible to the beetles.
And so, they figure maybe six or seven uses of oxalate, and in desert plants, plants make oxalate during the nighttime, create the calcium oxalate crystals, and then during the day in the desert, they have to close their breathing holes under the leaves in order to not dry out. But if you can't get CO2 through your breathing holes in your leaves, you can't produce energy as a plant. You need sunlight and you need air. So instead of using CO2 to do photosynthesis in the day, you use calcium oxalate. You break off that... Oxalate becomes a reservoir for carbon because there's so much oxygen, CO2, right? There's so much oxygen in that oxalate so perfect carbon-oxygen sync so you can make energy as a plant in the desert. So, like, there's this really cool stuff. The plants need it for their biology and they're using it against the predators, against them, and so in us, oxalate is quite toxic. In a plant, it's a clever strategy for survival.
Dr. Hedberg: Okay. So that was really interesting, and it's interesting that you bring up the structure of the oxalates because I do remember seeing some microscopic pictures of oxalates and I just thought, "Wow, that looks really deadly looking at them." The number of spikes, the size of the spikes, how sharp they look. And, you know, you've mentioned plants defending themselves and we see that not just with oxalates but also, you know, like, things like methylxanthines in coffee beans and cocoa beans are, you know, natural pesticides and a large human usually can detoxify those but sometimes small amounts or moderate amounts can also be damaging. So can you talk a little bit more about what foods contain oxalates and what foods people should look out for?
Sally: Yes, yes. So the animal kingdom does not have a lot of oxalates, although there's one rare exception of some giant snail in Asia that is not going to run across your menu anytime soon. It is the plant kingdom. It tends to be the seeds. There are four leafy greens that are particularly problematic and, unfortunately, a lot of people have flattened out the idea about where oxalates are to say all leafy greens are high in oxalate, and that's just not the case. There's spinach, which is the poster child of a high oxalate food. Beet greens and...Swiss chard is basically beet greens without the beet, is even worse than spinach. Swiss chard and beet greens are...Spinach is plenty bad enough, but that's even worse. And then there's sorrel, which is popular in other countries, not so much here unless you're going to upmarket restaurant. So those are leafy greens. Beans as a group are generally quite bad, the white beans, the black beans. The peas are not as bad, like a better choice would be black-eyed peas, green peas, and chickpeas would be much safer to use than black beans, for example.
Let's see. And the grains, it's almost all of them because the bran and the germ contains oxalate. So bran, whole wheat, bran-related things can really add up to a lot of oxalate. So the white flour stuff tends to be lower in oxalate but, of course, that's really devoid deficient food, and even that can add up. So even heavy bread users can get into a lot of oxalate, but I think the two most, or I would say the three most common foods that's universally interesting to modern people across the planet include potatoes and sweet potatoes. You know, the French fries, the tater tots, the potato chips, that is loaded because we eat it so much. Peanuts and peanut butter and anything made with peanuts, nuts in general, and then chocolate. So if you love your Reese's Peanut Butter Cups and your super dark chocolate and you like nuts, or if you're on a keto diet, you're probably super overloading your diet with oxalates.
Dr. Hedberg: Right. And one of the things that I've found is that the resources outline for oxalate content in foods tends to be highly variable. So on your website, I purchased the oxalate handout. And then if you compare that to, you know, some of the other handouts that are out there from certain universities and other...you know.
