But in order for you to understand what I say about fluoride and to make the best decision about fluoride, both in drinking water and toothpaste, et cetera, for you, you have to understand the remineralization process just a little bit, just a little bit. So a little bit of chemistry here, a little bit of structural biology, and this'll be fun.

I promise, even if you know no biology, no structural biology, no chemistry, you're going to like this part, and it's very simple. Those minerals that form the crystals within the enamel and some of the deeper layers of your tooth, or teeth, rather, those crystals form through a specific type of bond, and those bonds are very strong.

Think of them like Lego chains, but these are not just conventional Lego chains. These are Lego chains that when they stick, when two pieces come together, things are tough to pull apart. They're not indestructible, but they're tough to pull apart. And they're also special because unlike a string of Legos, like a single string of Legos, these bonds that form during remineralization of the teeth are interdigitated with one another, or rather, are at angles with one another that make those bonds especially strong.

Any architect or somebody that understands structural biology will understand that bonds can be weak or strong depending on whether or not they're linear, whether or not they're crossed, whether or not they're in lattices. There's a whole bunch of interesting angled forces stuff that the architects will understand, and the construction workers will understand at a very intuitive and in concrete level, no pun intended, and on and on.

But just think about it. A bond is only as strong as the number of different points at which it can resist shearing and pressure. So the way that these remineralization bonds form is through the addition of specific minerals at specific angles and the naturally occurring mineral that's responsible for the majority of these bonds in the enamel and teeth is called hydroxyapatite.

What a great name if you're talking about oral health, right, 'cause we use the mouth for a lot of things. You can think of the small list or long list of those things. There are many of them, you know, depending on who you are and what you like to do with your mouth.

But the point being that we do indeed eat with our mouth. Appetite is part of eating. So you just remember hydroxyapatite bonds, and they are very strong, but they're not indestructible. Acid can actually break those bonds. Okay, that's the demineralization process. Now, fluoride is a substance that is not a vitamin.

It's not a mineral. It is not an essential nutrient, but that in the last century, it was discovered, can actually replace some of the hydroxyapatite bonds in teeth and actually make those bonds hyper strong, super physiologically strong. Now, we'll talk about the safety considerations with fluoride in a little bit, because there are some safety considerations, but it was decided en masse in the United States and Europe that the addition of fluoride to the drinking water and to many toothpastes or tooth powders would be useful because it creates these super physiologically strong bonds within the minerals of the teeth.

And indeed it does, it does. Fluoride gets between those Lego pieces and makes them extra, extra strong. And this is why fluoride is added to the drinking water. But, and this is very important to emphasize, but nowadays there's a really polarized debate about fluoride, because some people out there believe that fluoride can disrupt thyroid health, might even be disruptive for brain health.

Certainly if fluoride levels are too high in drinking water or any substance, it can be very dangerous. It can be a poison, but of course the dose makes the poison, right? Fluoride itself may not be poisonous at very low levels, but there are really two camps now that have formed.

And I'll just illustrate those two camps by virtue of what's happening right now. Right now in the state of California, there is a major lawsuit against the government because people want fluoride removed from the drinking water because of the long list of bad things that excessive, I wanna highlight excessive fluoride can do for bodily and brain health, especially in kids, but also in adults.

At the very same time, meaning right now, there is also a major lawsuit, this one in Buffalo, New York, from mostly parents who are suing the city of Buffalo, saying that there was not enough, maybe even zero fluoride in the drinking water for some period of time. And as a consequence, their children's teeth or oral health or both is depleted and they are suing for damages.

Okay, so this is a really polarized camp. Now I did a full episode of the Huberman Lab Podcast all about water. And I talked about fluoride levels, which levels are thought by the CDC to be safe, which levels are not thought to be safe. I talked about some of the theories as to how fluoride might disrupt function of the thyroid and some considerations there.

Please check out the timestamp in that episode. I linked to that timestamp in the caption for this episode. But the important point here is that if you are at all concerned about fluoride in the drinking water, the simple answer is to just filter the water that comes out of the tap.

If you're concerned about fluoride, then I suppose you'd probably wanna avoid toothpaste that have fluoride. Indeed, there are some. I will provide links to some of those in the show note captions for this episode. There are a variety of these zero fluoride toothpaste that have started to accumulate. But keep in mind that when fluoride is introduced into the bonds of the minerals of the teeth, they do make the teeth really, really strong.

But, and all the dentists I spoke to emphasize this point, the bonds that form are not the natural bonds. Now, the fact that they're not the natural bonds doesn't necessarily mean that they aren't good for us or that they're bad for us. But the bonds that form when viewed under what's called electron microscopy look different.

They look wavy. They're not smooth bonds. And they do increase the resistance to different forces, including cavities or acid that would create cavities to be specific. They make the teeth stronger structurally, so resistance to chipping, et cetera. But there is a growing concern about excessive fluoride, which by the way, if you drink a lot of tap water, you're going to be exposed to more fluoride than if you drink less tap water.

That's just kind of stands to reason, but people don't really talk about this, right? When you talk about X amount of fluoride by concentration in a given liter of water or gallon of water, you also have to ask, well, how much tap water are you drinking every day? Okay, you have to ask that question, right?

It's not simply the concentration, it's how much you're ingesting overall. And that's something that's much harder to control for. Again, in the water episode, I talked about ways to eliminate or reduce fluoride in the drinking water if that's a concern of yours. But if you want to know why there's fluoride in drinking water, it's because governments figured out, hey, well, if we want to reduce tooth decay, what's the simplest low cost method to do that?

Well, it's to put fluoride in the drinking water. And you now also now know why there's fluoride in a lot of toothpaste. But given the concerns about thyroid health, potential concerns about brain health, now you also know why many people, including some dentists that I spoke to, are not big fans of fluoride, both for children and for adults.

So you just have to make a decision for you. I'm not here to tell you what to do. You just have to decide, are you pro neutral or against fluoride in your drinking water? And if so, are you going to filter? Are you going to completely avoid drinking any water, maybe even cooking with any water from the tap and on and on?

But now you know why fluoride is in drinking water and fluoride is in toothpaste. If you're somebody who's concerned about fluoride in either or both of those sources, well, then what you really want to think about and what most of us probably should be thinking about anyway is trying to increase the remineralization state of our teeth and mouth in ways that don't create the opportunity for any other health hazard.

And I will say this as well, which is that there's some data, not a lot, but some data that fluoride might not be so great for our oral microbiome. And as we'll soon learn, the oral microbiome is critical for our oral and overall health. (upbeat music)