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I need to make some kidney stones and not in the traditional way, because I wanna try out a potential home remedy for preventing them.

That's great, we got calcium oxalate crystals.

Kidney stones come in a couple of different types.

You have calcium stones, you have uric acid stones, you have cystine stones, and you have struvite stones, and all of those describe what it's made out of.

And so yes, I also did wonder what struvite was.

So let me lemme show you that.

Struvite is magnesium ammonium phosphate, and it turns out you only get this kind of stone if you've had a UTI with a type of bacteria that turns urea into ammonia through an enzyme called urease.

Biology is wild.

We're not talking about that.

What we care about today are the most common type of kidney stones called calcium stones.

These are typically things like calcium phosphate or calcium oxalate, or sometimes a little bit of both.

So what I'm gonna be trying to make today are calcium oxalate stones.

And I had a plan to do this.

So my plan was to mix calcium chloride with sodium oxalate and then get out calcium oxalate and salt.

This is what I wanted, that's the calcium oxalate.

However, when I opened up my package from Amazon, I did have calcium chloride, that's great.

But then instead of the sodium oxalate, they sent me sodium perborate tetrahydrate, what's that?

I noticed because it had a lot more danger, danger warnings on it than I anticipated.

So now we have is calcium chloride plus sodium perborate.

and that, do you know what that makes, 'cause I don't?

I don't know what that makes and I'm not gonna find out.

You can figure that out if you want to.

We're not experimenting with this.

And so we improvise because I don't throw things out.

And so I have a leftover bag of oxalic acid from the antifreeze video, ethylene glycol, because I was showing the terrible things that happen in your body if you drink antifreeze, which is basically kidney stones just everywhere.

Anyway.

So now what we have is calcium chloride plus oxalic acid, and those together will also make calcium oxalate.

But instead the other product will be hydrochloric acid instead of just sodium chloride, which I'm a lot less excited about, so thanks, Jeff Bezos, just making me make hydrochloric acid over here.

Did I balance this right?

Calcium, calcium, two chlorides, one chloride.

Oh, oh, no.

Two HCL.

Now we're balanced.

So this is called a precipitation reaction.

The ions in the solution are so concentrated that when they combine, they're no longer soluble.

Oxalic acid is a pretty weak acid and it won't totally dissociate in water right away, but as the calcium starts precipitating out with the oxalate that's available, more of it will dissociate to replace it.

Yeah, oh yeah, that's working.

I love it when chemistry works.

This is not in the script, but I'm adding it in because I think it's kind of cool to understand here.

So oxalic acid, you know, when it's just sitting in that bag like that, has this kind of structure.

However, when you put it into water and we talk about that dissociation, what happens is that you get oxalate.

And so we lose these two hydrogens.

What a funky looking molecule, right?

And the reason why this works is because actually those negative charges are shared between the two oxygens.

So sometimes you can also write it like that, so that like these two oxygens are sharing that negative charge, and these two oxygens are sharing that electron kind of thing.

And so this is the like 2 negatively charged oxalate that then our calcium can just like hang out by.

So that's how this oxalate is binding to this calcium, cool?

Cool.

About two years ago, I woke up in the middle of the night and thought that my body was trying to implode, and it turns out that I had a kidney stone.

And if you've had one too, you know that you wanna try to avoid getting another one.

Now I heard that one way to prevent them was to put lemon in your water.

But like do you know how little lemon juice there is in a slice of lemon?

It's 1.62 grams, but I also got two seeds in there.

Stomach acid is like 1.5 to 3.5 pH, lemon juice is about two, so like could adding just a slight amount of acid to your stomach actually have any effect on your kidney stones?

That didn't seem right.

And actually that is right, because it has nothing to do with the acidity of the lemon, mostly.

So typically when you have too much calcium in your diet, what happens is that your kidneys just flush out all that extra calcium in your urine because that is what your kidneys do.

They take all the stuff that your body doesn't need, stuff like urea and ammonia and extra minerals and vitamins and toxins and electrolytes, and all that kinda stuff that is too much in excess in your blood, and it gets rid of it.

But the way that it works is super cool, and I love the way that the nephron works, because what it does is you have a bundle of capillaries called the glomerulus, great name.

So your kidney pushes all the blood into the glomerulus at high pressure.

And what happens is that everything other than like big proteins in your blood gets pushed out into a space called the Bowman's space, which I also think is a great name.

So you have your blood, everything other than big chunky proteins gets pushed out, and then your body decides selectively what it wants to put back in.

So all these extra salts and ions and junk end up in your urine, including things like calcium and oxalate, which make our calcium oxalate stone.

At normal levels, both of these ions just get diluted in your urine and excreted out.

However, if the levels get too high, either because you're dehydrated or maybe there's something funky going on with your metabolism, they can come together to create these crystals, basically what's happening right here in this tube.

So what about the lemon?

The lemon juice could stop it because of something called citrate.

You're probably familiar with citric acid, which is what gives lemons their tang.

However, when citric acid dissociates into its anionic form in something like physiological blood levels, you get citrate.

Citric acid, citrate.

Very similar to the oxalic acid and oxalate we talked about before.

So we have citric acid which dissociates into the anionic citrate.

Now, once again, we've lost these hydrogens off of these OH groups, and now they have a negative charge.

And you might be wondering why an OH group can just like lose a hydrogen, that doesn't happen in something like an alcohol, right?

And again it is because there's actually resonance structures happening here between this O and this O-.

So here, this double bond O, OH, this is a carboxyl group, and this can donate those Hs because of the way that that electron can be shared between the double bond and O and the O-.

So again, you could also draw this carboxyl group that's lost a hydrogen here with this resonance structure.

So actually these two would be sharing this negative charge, and same thing with this carboxyl group here and that one there.

So they're sharing that electron.

I feel like if you're actually a chemistry professor, you must have to spend so much time like perfecting your handwriting.

And again, citrate is how citric acid exists at normal physiological pH.

So if you're drinking lemon juice, your body is dealing in citrate.

And so doctors will sometimes actually prescribe citrate drugs to patients who have recurrent kidney stones because this negatively charged citrate can actually go around in your urine and bind to free-floating calcium, preventing it from binding to the oxalate and forming calcium oxalate kidney stones.

Citrate is a chelator, a name for an organic molecule that binds to metal ions like calcium.

'Cause remember you could look at this and it has a 3- charge on it, so it combines to positively charge calcium ions.

Okay, so at the top we have our kidney stone equation where calcium and oxalate come together to form calcium oxalate kidney stones.

But if we add citrate into the equation, now we can also get calcium citrate, and that will push the equilibrium of this top reaction to the left away from the kidney stones.

So now we are getting fewer kidney stones, which is a positive thing, we like that.

So now let's try it in my little kidney stone test tube.

All right, maybe we need more than five mil.

I think that's not helping.

For kicks and giggles.

Does not look very different.

So actually I think everybody just needed a minute to work.

So I think there's actually a pretty clear difference between citrate, no citrate, and also all the precipitate in here was starting to fall out of solution, so you couldn't see the difference.

But like citrate, no citrate, crystals, no crystals, kidney stones, no kidney stones.

Okay, now that these have been sitting for a bit, I think there is a clear difference between the sort of straight kidney stone reaction and the one with citrate.

I think you can tell like a big difference.

The citrate really prevented that precipitation.

But let's look for some crystals.

And yeah we have... That's great, we got calcium oxalate crystals.

But what I'm gonna put next to this is the one with citrate.

Without citrate, with citrate, there's just like dust that was on the slide.

So drinking lemon juice, lemonade, and even some store-bought mixes can increase the amount of citrate in your urine, decreasing your chance of getting kidney stones.

Now drinking lots of those fluids also means that you can be extra hydrated.

And did you know that you were supposed to be producing like between 2 and 2 1/2 liters of urine per day?

That's a lot of urine, that's a lot of pee.

I mean, I've never measured, I'm not going to measure.

I don't like where this is going.

Okay, so being properly hydrated means that the concentration of all the things we're worried about is lower, so lower chance of making stone.

But not every citrate containing juice seems to work the same way.

For example, in some studies, orange juice seems to have the most protective effect against kidney stones, but grapefruit juice could actually increase your risk of getting kidney stones, weird.

We're gonna try all three anyways.

Also, remember how I said it was mostly not about the acidity?

Ironically, some of these acidic juices can actually make your urine more alkaline.

When that same citrate hits your liver, it can be metabolized into bicarbonate, which is alkaline.

That bicarbonate could make your urine less acidic and prevent a different type of stone, uric acid stones.

Less acid, less acid stones, makes sense.

So it's not all about the acidity, but it does play some role.

So obviously I ran this experiment three more times.

I have equal parts calcium chloride and oxalic acid in these tubes and then I added lemon juice, grapefruit juice, and orange juice.

And to prove that it is not just acid that makes the difference, I also made one with vinegar.

Oh yeah.

We do have crystals.

Here's the thing that I think is interesting though with the lemon one, is that, do you see these like sort of diamond-shaped crystals?

I don't think we saw many of these sort of diamond shapes before, which reminds me of more of like a tetrahedral crystal, something like salt.

Okay, and now we go to orange.

There's so much other junk in orange juice.

It said no pulp, but there's for sure a pulp in here.

These crystals are so much bigger.

Look at these like diamond tetrahedral crystals.

There are different shapes in here, so I do wonder if it's forming other stuff, kind of cool.

Next up, we got grapefruit juice and vinegar, not together.

It's hard, right, 'cause there's definitely pulp in here too.

It's funny, I don't see any of those like tetra... Oh, there is one.

All right, there's some tetrahedral crystals in here too.

It's really hard to do a one-to-one comparison of like more or less crystals with this.

Yes or no is pretty easy, but like I don't have the precision here to really say if one has more or less.

Let's grab vinegar, we got those calcium oxalate crystals.

Vinegar didn't solve it.

Now obviously I am not that kind of doctor and you should not take medical advice from a random YouTube video.

But if you happen to be a Falcon tube with a recurrent problem of kidney stones, I would recommend citrate and orange juice.

When I wrote this, I actually wrote, "I'm not a doctor," and then I was like, "No, I am.

I'm just not that kind of doctor."

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