If you read the ingredient labels  on your favorite chewing gum,   you may see a sweetener called xylitol.  Which is a scary sounding word.

Like, it’s got the letter X in it, so  surely that stuff can’t be healthy! But it turns out there’s a lot of evidence that  xylitol can do a bunch of good things for us,   like fighting infections, managing blood  sugar, and even helping reduce preterm births.

So pop some gum, and let’s get into it. [♪ INTRO] Before we talk about what xylitol can  do, let’s talk about what it even is. Xylitol is a naturally-occurring sugar alcohol  that’s found in some fruits, mushrooms, and other   plant materials, and we’ve been putting more of  it into our food since the mid-twentieth century. And a quick sidenote: while we know that  xylitol is regarded as safe for humans,   it is very dangerous for  dogs.

So no sharing with Fido! There are other sugar alcohols you might see on  food labels, like sorbitol and erythritol. These   all have a chemical structure that allows them to  stimulate the sweetness receptors on our tongues.

And xylitol is unique among the sugar  alcohols because its shape lets it   bind to those receptors really well,  making it just as sweet as table sugar. But the structural differences mean sugar  alcohols are broken down differently and   more slowly in the body than table sugar. So  our bodies don’t absorb them as efficiently.

This means that while xylitol does  have some calories, it contains   around forty percent fewer calories  than sugar in terms of sheer energy. Which may be why we started putting  it in our food. And as it turns out,   that was a sweet choice with a lot of added  benefits, which start with your first bite.

If you’ve heard of anything  that xylitol is good for,   it’s probably that it’s great for your  teeth and gums. There are plenty of   studies that show it can prevent tooth decay,  especially in cavity-prone kids and adults. And you might think that the only  reason that stuff sweetened with   xylitol doesn’t rot your teeth is just  that there’s not as much sugar in it.

Since xylitol is found in a lot of  sugar-free gum it might seem like   the dental health benefit is either from  replacing sugar or the gum chewing itself. Which is true, since chewing  stimulates the production of saliva,   which washes away substances that erode  tooth enamel. So chewing on any kind of   gum will help at least a little bit,  as long as it’s not a sugar-bomb.

But there’s also something about xylitol itself  that packs a few cavity-fighting punches. First, multiple studies suggest  that xylitol impedes the growth   of bacteria that contribute to cavity formation. It seems to do this by getting in through the cell   walls of certain types of pathogens  and disrupting their metabolism.

Cavity-causing pathogens love sugar, and  the more they get, the more they can grow. When they digest that sucrose, it creates  acidic byproducts that eat away at our teeth. But when the same bacteria chow  down on xylitol instead of sucrose,   their metabolisms get jammed up and  they eventually run out of energy.

So giving these sugar-hungry microbes  xylitol stops them from multiplying and   sticking to our teeth, and prevents them  from making that decay promoting-acid. This is a big deal, because bad  oral bacteria have been implicated   in various diseases like cancers,  heart disease, and even Alzheimer's. So xylitol’s ability to basically  starve unwanted pathogens in the mouth   could have ripple effects all throughout the body.

Not only can it kill cavity-causing bacteria and  dial down oral acidity, but combining xylitol   with certain calcium products and fluoride may  even help prevent the demineralization of teeth. Xylitol binds to calcium, creating  a structure more resilient against   acid damage or demineralization. And it  allows that calcium to stick into your   enamel before it can get washed  away into the digestive tract.

And not only does that help  prevent demineralization,   some studies suggest that it can even help  re -mineralize enamel that people can lose   over time. So early stages of tooth  decay could be reversed with xylitol. This is still really early days,  so please do not try this at home,   but who knows?

Maybe someday xylitol will  keep your dog’s mouth as healthy as yours. And Xylitol’s ability to strengthen  your tissues isn’t just restricted   to the mouth. It may also help your bones.

See, your bones are actually changing a  lot more than you might think they are. There’s a constant rhythm of new bone  getting built as older bone gets recycled,   all of which keeps your bones strong and healthy. At least, when it’s all working like it  should be.

Sometimes the recycling part   outpaces the rebuilding bones, resulting  in issues like osteoporosis or arthritis. And one way we might be able to  fix that mismatch is with xylitol. This improvement is partly  due to increased acidity,   not directly around the bones, but in the gut.

See, sometimes the reason your bones can’t rebuild  as fast as they need to is if you’re not absorbing   enough calcium in your diet. But when xylitol  enters the mix, it decreases the pH in your gut,   helping your intestines absorb more calcium  and minerals to use for bone rebuilding. Now to be clear, most of the studies on  xylitol’s role in bone-building have been   done on rodents, where adding  xylitol to their feed resulted   in decreased bone resorption and  increased bone density in rats.

In at least one study, researchers saw the  bone-strengthening effects of ingesting   xylitol just a couple days after the first dose. However, the amounts studied  were like, a lot of xylitol,   probably way more than a human  would want to consume in a day. But a 2022 study using rabbits suggests that   actually applying xylitol topically to  bones may also help rebuild them too.

In the study published in the Journal  of Applied Veterinary Sciences,   twenty-four white rabbits were anesthetized  and had their femurs drilled into. Ouch. Amazingly, the group of rabbits that  had xylitol applied directly to the   break had way more new bone tissue  than their untreated counterparts.

That same study also tested whether  xylitol in food sped up bone healing,   and while they found that rabbits that  got extra sweet treats did heal faster   than the control group, and both oral and  topical xylitol had faster rates of healing. Who would’ve thought that the secret to faster  bone healing was adding a candy coating? But before we keep talking about  the many benefits of xylitol,   let’s talk funding.

Specifically, ours. Thanks to Brilliant for  supporting this SciShow video! Brilliant is an online learning platform where you   can build your knowledge through  their fun and interactive lessons.

Their easy to use platform lets you  expand your horizons at your own pace,   meaning that you’re not limited to  a traditional classroom schedule. With Brilliant and a smart phone, you can  learn any time, anywhere. In the doctor’s   office waiting room?

Easy. Waiting for  your train? Absolutely.

On a date? I mean,   maybe not the best idea, but that’s your  call. Brilliant certainly won’t stop you.

To try Brilliant for free,  visit brilliant.org/scishow,   scan the QR code onscreen, or click on the link in   the video description. You’ll also get  20% off an annual premium subscription. Xylitol isn’t just great for  the parts of your body made   of minerals.

It can be super  beneficial for your gut, too. Part of what makes xylitol special  is the way that it’s digested. It’s something called a prebiotic,   a type of fiber that feeds the beneficial  bacteria in our gut and helps them thrive.

See, our human tissues can’t  digest xylitol all alone. But certain types of good bacteria that normally  colonize healthy digestive tracts can take xylitol   in and happily ferment it into short-chain fatty  acids, which help you absorb water and minerals,   balance the pH of the colon, and feed  even more of our microbial friends. For instance, in a 2024 study published in  the journal Food and Chemical Toxicology,   researchers used a colon simulator with  fecal samples from children to study   what happens in digestion with or without xylitol.

They found that xylitol increased  the production of butyrate,   a fatty acid that provides energy  to the cells of your colon. Xylitol’s prebiotic power can be a good thing,  but it’s also kind of a double-edged sword,   specifically because it can  also have a… laxative effect. Xylitol and other sugar alcohols  have been known to cause diarrhea,   especially in people who are more sensitive to  them.

This is one reason why there’s a general   warning against overconsuming it, which, of  course, is true of pretty much all substances. This excessive pooping with too much  xylitol happens because it’s hydrophilic,   meaning it draws water into itself, including when   it’s in the digestive tract. And that  extra water helps… move things along.

But that also means that a dose of  xylitol may also help with constipation. Some research even suggests that  several doses of xylitol after   surgery can help patients’ bowels  start moving again more quickly,   reducing the amount of time patients  need to wait around in the hospital. So xylitol could be just as good for you  on the way out as it is on the way in.

Yet another way that xylitol’s structure makes  it distinct is that it doesn’t require as much   insulin to break it down as sugar does. Plus, it  may help control the accumulation of body fat. Part of this is for the obvious  reason—replacing sugar with a   lower calorie sweetener is going to  naturally mean lower blood sugar.

But again, xylitol seems to have  its own diabetes-fighting tricks. Xylitol can stimulate enough insulin secretion at  the right dose to help us process carbohydrates,   and in diabetic individuals, it might get and  keep insulin levels within a healthy range. You can think of insulin like  a key that unlocks our cells,   allowing glucose in to be used for energy.

For people with type 2 diabetes, either the  pancreas doesn’t produce enough insulin,   or their cells don’t seem to get unlocked by that  insulin key as efficiently,or sometimes both. That prevents sugar from getting into  their tissues to be used as energy,   and causes it to build up in the blood. This excess sugar often  ends up being stored as fat.

A study in mice suggests that ingested  xylitol may help cells respond to insulin,   allowing them to take in and  process glucose more efficiently. There’s also evidence, largely in rats, that  high doses of xylitol may be able to help   pancreatic cells produce more insulin, which  may also reduce the accumulation of body fat. All in all, the blood sugar benefits of this  sucrose alternative make it pretty…. sweet.

We’ve covered how xylitol fights bacteria  in your mouth. But it turns out it has   infection-fighting properties  beyond your pearly whites, too. In the right conditions, xylitol seems to be  able to bust biofilms, which are colonies of   microorganisms that stick to various surfaces  in clingy layers.

If you’ve ever dealt with a   stubborn smelly drain or slipped on slimy rocks  in a river, you’ve had a run-in with a biofilm. The plaque on our teeth is  an example of a biofilm too. And while some biofilms are pretty annoying,   some other biofilms are actually pretty  helpful in the right circumstances.

But one place we don’t want biofilms  is on our skin. While everyone’s skin   is teeming with various species of  bacteria, people with bad eczema   tend to have specific types of bacteria  populating their skin that aren’t found   in people without the condition, at  least not in such high quantities. And there’s evidence that xylitol can  damage these unwanted skin microbes.

A 2005 study published in the Journal  of Dermatological Science found that a   xylitol solution could dissolve a biofilm of  Staphylococcus bacteria that researchers grew   on collagen-coated plastic, and it could also  prevent the formation of new staph biofilms too. The same researchers also conducted a small  clinical study on six eczema patients in Japan   back in 1999. They found that application of  a cream that contained 5% xylitol along with   other active ingredients significantly reduced  the presence of this problematic pathogen.

And when applied topically, xylitol may also  help skin with wound healing by reducing   moisture loss and accelerating  the repair of the skin barrier,   which is a layer of skin  tissue that holds in moisture. Some in vitro studies suggest that xylitol  may also fight infections in the nose, throat,   and ears. It may even help inhibit or kill  pathogens that cause all kinds or ailments,   like ear infections, pneumonia, and flu,  although the studies in vivo, AKA in us, vary.

And there’s even more. These  infection-fighting benefits   of xylitol may help the next generation  too, even when they’re still in utero! Researchers conducted a randomized  controlled trial lasting over three   years of over ten thousand pregnant or  soon-to-be-pregnant people in Malawi,   a country with a really  high rate of preterm birth.

In their paper published in the journal Med in  2024, they reported that expectant mothers who   chewed xylitol gum had a whopping 24% reduction  in preterm births over the course of their study. See, researchers have known for a while that  periodontal disease during pregnancy is associated   with negative birth outcomes. And since people  in Malawi also have high rates of periodontal   disease, these researchers thought they could  hit both birds with one, uhh, pack of gum.

So it’s possible that this  positive effect of xylitol on   pregnancy outcomes is a byproduct  of reducing periodontal disease. In any case, it’s pretty amazing that  a simple ingredient in candy may help   fetuses and newborn babies whose  teeth haven’t even come in yet. So there’s a lot that xylitol  can do for us, from head to toe.

And it’s a great reminder  that some substances that   might sound a bit scary can have their perks, too.