The TRUTH about tofu

So what is the truth about tofu and kidney stones? Let's talk about that. Welcome back to the Kidney Stone Diet Podcast, the show about reducing your kidney stone risk and living your best life.

I'm your host and fellow student, Jeff Sarris.

And I'm Jill Harris, your kidney stone prevention nurse.

So this one, tofu, this is a listener question that we're going to get to in a second. If you have a question, you can find a link in the description where you can leave us a voice message that we can then feature on the show in the future. But let me jump right over to Steve's question.

Hi, Steve in Seattle. I think you've done a show about soybean oil, but I don't know of anything that addressed tofu. I tend to consume a considerable amount of tofu, often in Chinese dishes.

So it could be eating at least a quarter to half a block of tofu in one sitting. That would be as much as 8 ounces. Wondering if there's concern there for tofu's oxalate content, or maybe it contains calcium that kind of negates the oxalate content?

Would love to have your insights. Appreciate you guys and the show. Thanks so much.

So I just looked up this. So for a half a cup of tofu, you know, we have 434 mg of calcium in there. So it's a nice source of calcium.

And so let's put that on the side. So and but it differs depending upon, guys, turn it around, must turn, look at your labels. Tofu, the calcium in tofu can be anywhere from 250 mg to 800 mg per half cup serving.

So people don't understand that, you know, if they chose tofu, and I say it has, however, if I've got tofu, which I have in my house, if I turned it around and said it has 400 mg of calcium in it, people think that all tofu does. And all foods have different amount of varying different amounts of ingredients and salt and calcium.

Every product you have is going to be something different. So all tofus will not have the same amount of calcium is what I'm trying to say, folks, okay? So it is, it can be a good source of calcium.

So that is that is true, Steve, but let's put this all together. So the first thing he asks is, "Hey, Jill, I'm eating a lot of tofu." I think he said up to 8 to 10 ounces per serving? That's what he said, I believe.

Okay, so this is a lot. So Harvard did study tofu. They studied soft tofu, and for 3 and a half ounces, it's 10.6 mg of oxalate.

So let's just round up, because who wants.6 anywhere? So let's just say it's 11 mg of oxalate for 3 and a half ounces. He's eating more than double that, so he's probably getting like 30 mg of oxalate, no, Jeff?

If he said 8 to 10 ounces, and you're much better at that th- than I am, math.

Yeah, yeah, he did say 8 is sort of the amount that he typically has.

Okay, so we multiply 8 times 4, and that's—

Yeah, so that's 32.

32, okay. So, Steve, you're getting about 32 mg of oxalate. Also, Harvard studied soft, soft.

There is firm, there's super firm, there's extra firm, holy guacamole firm, you know, you've got to look at the label. Will it be that the firmer it is, it will be more nutrient dense, meaning will, you know, there's going to be less liquid in that? Typically, that's what that means.

So will there be more oxalate in it if you're using firm, Steve? Could be. But then most of you are also squeezing that tofu so you get all the fluids out, so I mean, you know.

So do you really have to take all this into consideration? Not really. I don't like getting in the nitty-gritty, I'm just talking about it, okay?

So what we know is Steve likes tofu, as many of my patients do. Many of my patients just hear the word tofu, and all my vegans and vegetarians give it up, and they never go to kidneystonediet.com and look at the Harvard list, put tofu in the search, and then it's there. So tofu is listed on the website.

But because around the block, around the internet, around town, tofu is thought to be high, I can't tell you how many patients when they come to me for a consult, and they tell me all the foods they have taken away because they're so afraid of oxalate, and I bring 95% of them back. They're like, "Are you kidding? Really, Jill?" They're a little bit nervous.

I explain, I've looked at thousands of urine collections. When I give my advice on the first call that I give people, and then when they call me for the follow-up test, look what I did now. I'm looking, after they take my advice, their oxalate level is exactly where it should be, it's low.

I've had some people that come to me, their oxalate level is over 100, and the second time they talk to me, they show me the follow-up test, and now it's 22. And that's a case study on Dr. Coe's website.

So the reason I say all that is I want you guys to understand that I would never put you in harm's way, ever. So I'm looking at data all day long based upon the advice I give. The advice I give is based upon years and years of research.

And you can Google Fred Coe, C-O-E, University of Chicago Kidney Stone, and see where all that research is. It's not all his research, he's combined, he's brought together all the leading researches in kidney stone disease and put it on his website for kicks and giggles, that's what he does, for free, to leave it out there in the ethers.

Okay. So Steve's like, "Jill, I took a nap, what are you talking about?" Shut up, Steve, here we go. So it's about 32 mg of oxalate you're eating per session.

You get 100 mg of oxalate a day. If you'd like to spend your oxalate dollars on that tofu, absolutely. And we do know that it has calcium in it.

So people will say, "Well, if that's the case, Jill, why can't I have spinach? It too has calcium! Actually, Jill, I'm a vegan, and I was eating spinach for calcium." But spinach is so high in oxalate, there's not enough calcium that's going to bind that and flush it out of your system.

But the tofu is a lot less. He's having a fairly nice amount of tofu, 8 ounces, and I wouldn't have more than 8 ounces, let me keep it there, because you're getting, depending upon the tofu, I'm sure, just say, just let's just say, let's round up because I like rounding up to be safe, about 35 mg of oxalate. And then you're going to want to spread it throughout the day, so I would cut it at 8 ounces.

And you are getting some calcium with that, and it's not a crazy amount of oxalate. Gorgeous, I say, "Manja!" Go ahead, Steve, enjoy that. I love the question.

I don't think anybody's asked us about tofu before, so it's a great question, and it's a very common food. It's one of the most common foods, actually, which could be a good title, Jeff, that people take away and they don't need to.

Yeah, and it's surprising with all these episodes we haven't touched on tofu specifically yet. So, yeah, thank you so much, Steve. And if you have a question, the website is right in the description, you can click there, leave us a voice memo, and we will feature your voice on a future episode.

I think with that, we'll wrap. Thank you everyone for tuning in, and we'll see you next week.

Thank you, Steve. Everybody, have a good week.