Evidence is mounting that the effects of oral health on the body are not localized to oral tissues only. A study in 2020 found that compared to a healthy control group, saliva from patients who recently had strokes showed increased biomarkers for inflammation and protein oxidation, suggesting a link between oral health and stroke risk.^[4] Another study published in the same year found a link between periodontitis (infection of the gums) and high blood pressure.^[5] Furthermore, some evidence shows that poor oral health is associated withcan predict cardiovascular and respiratory disease mortality.^[6] The effects of oral health are not limited to the cardiovascular system, however, as periodontitis has been linked to at least 50 systemic diseases.^[7]. Although the details and mechanisms are still being sorted out, it is clear that there is a relationship between oral health and systemic health.

Did you know that orange juice causes about as much dental erosion as soda, on a per-cup basis? Luckily, dose matters, and people are more likely to drink multiple cans of soda each and every day than multiple glasses of orange juice.

But that brings up an interesting question: ascorbic acid (aka vitamin C) is at fault for orange juice’s erosive effect. So what happens when you drink a powdered vitamin C supplement, which can contain up to 10 times more vitamin C than orange juice?

Let’s go through the existing research, in order to better understand the potential risk.

What does the research show?

In 2012, a meta-analysis found that chewing vitamin C tablets (in the form of ascorbic acid) significantly increased dental erosion. Chewable tablets, gummies, and liquids all contact the teeth, so a similar line of reasoning applies for each. Gummies and tablets may stick to teeth more, and powdered drinks less, but powdered drinks often contain more vitamin C. Swallowed pills, however, are in the clear.

So what exactly happens to the tooth enamel?

Oral bacteria are the most common culprit for stripping away tooth enamel, stealing some of the sugar you eat and producing enamel-eroding acid from it. But acid in the mouth can also come from non-bacterial sources, such as from chronic vomiting or directly from things you eat and drink. The usual suspects are soft drinks and acidic foods and beverages, while milk and yogurt can help protect enamel.

More specifically, enamel can dissolve at pH levels under 5.5, and chewable vitamin C tablets have a pH of around 2.3. Now that isn’t quite as scary as it sounds, since saliva can protect you by buffering some acid. But this only works to a degree, and continual exposure will lead to enamel loss. One study showed that salivary pH can drop quite a bit with vitamin C tablets, allowing enamel erosion to proceed, and a typical dose of 500 mg will lower the pH for up to 25 minutes.

Vitamin C supplements that contact your teeth (chewable tablets, gummies, liquids) can impact enamel to varying degrees. Exposure time and frequency of dosing are important factors.

What should you watch out for?

Watching might not actually help! You might not notice dental erosion at all, since the process can be slow, and tooth sensitivity won’t show up as long as the dentin under the enamel isn’t very affected. That means going to a dentist regularly is quite important.

As far as preventive measures, it depends on how safe and/or obsessive you want to be.

If you frequently drink those popular effervescent vitamin C packets aimed at reducing colds (oh, the lengths we’ll go to at Examine.com to avoid brand names …), drinking them through a straw will help avoid prolonged contact with our teeth. And whether you use vitamin C powder, tablets, or gummies, brushing within an hour of taking them substantially raises your risk for dental erosion.

Using Occam’s razor, another method would be to simply not use these products. Plain old ascorbic acid is much cheaper (albeit not as colorful and artificially tasty), and sporadically taking vitamin C isn’t shown to help prevent colds.

A third method is to avoid prolonged exposure. There isn’t much data out there, but six weeks of chewing a lot of vitamin C didn’t impact oral health in one trial, while a case study of three YEARS of nearly continuous vitamin C chewing and sucking led to massive dental erosion. Another case study also showed that three years of chewable vitamin C (but limited to three tablets a day) caused severe dental erosion.

Obviously, there’s a wide range in between six weeks and three years that has not been studied. Plus other other vitamin C forms haven’t been studied much, although vitamin C chewing gum actually helped reduce gingival calculus (which is basically hardened plaque, with plaque being the home of bacteria).

A final option would be to take a non-ascorbic-acid form of vitamin C, such as liposomal C or a mineral ascorbate. These are more expensive than ascorbic acid though.

Considering the large number of people who take vitamin C supplements, there’s surprisingly little research on vitamin C and dental erosion. While no effect was seen after six weeks of vitamin C tablet chewing in a very small trial, years of chewing has been associated with very severe enamel loss. Unfortunately, nobody knows how long you’d have to supplement to cause damage, and this could also vary depending on other oral health factors.

Luckily, vitamin C can be easily obtained in forms that aren’t powdered, chewable, or gummy. Just go to the grocery store and look for an amazing non-proprietary food product called: Fruits and Vegetables™, which also taste better than supplements. If you want to supplement for certain health goals, consider a method that doesn’t give your teeth prolonged exposure to ascorbic acid. For example: swallowed pills, liposomal C, or mineral ascorbates. If you drink powdered vitamin C or use chewables or gummies, consider swishing water around afterwards to reduce the enamel impact.

Please, for the love of all that’s evidence-based, don’t routinely brush your teeth after taking vitamin C chewables, gummies, or liquids. This same line of reasoning applies to brushing after drinking your morning orange juice.

Most people have chewed gum at some point in their lives. It’s possible you’re chewing gum right now as you read this post. But are there any health benefits to chewing gum? How about detriments?

Oral health

There’s one benefit that chewing gum aficionados are often aware of: improved oral health.^[8][9] After eating a meal, some of the leftover food stuck in your mouth gets broken down by oral cavity microbes, which produce acidic byproducts that can damage our teeth.

Chewing gum may offset this by increasing saliva production, which helps neutralize these acidic compounds.^[10] Recent research has also found that gum can trap and remove bacteria from your mouth.^[11]

Chewing gum containing xylitol has shown extra benefit, since xylitol reduces levels of the acid-producing (and hence enamel-eroding) bacterium mutans streptococci.^[12]

Alertness

The majority of studies that looked into chewing gum before cognitive tasks showed increased alertness and sustained attention, ^{[13][14][15][16][17][18][19][20][21][22][23]} while one of them showed mixed results with decreased alertness but increased sustained attention.^[24] One systematic review summarized the findings of 22 studies that investigated the effects of chewing gum on sustained attention and found that more than half of the studies found positive effects.^[25]

The process of mastication (chewing) seems to increase overall blood flow to the brain as well as to specific brain regions, which may be the mechanism responsible for increasing attention and alertness. Studies in various populations are lacking though. For example, one study found that chewing gum had a negative impact on vigilance in children with ADHD, and also had no impact on sustained attention.^[26]

Chewing gum seems to increase alertness and sustained attention, although the evidence isn’t conclusive, especially for specific populations.

Anxiety

The effects of chewing gum on anxiety and stress also seem to be fairly consistent. A number of studies have found that chewing gum decreases anxiety and stress,^{[27][28][29][30][31][32][33][34][35]} but a few have also found no detectable effect.^[36][37][38]

The mechanism isn’t fully understood, but gum chewing has been found to increase cerebral blood flow and alter brain waves, and these effects may also be influenced by gum flavor.^[39][40]

Chewing gum seems to have a somewhat consistent positive effect on anxiety and stress.

Appetite

A few studies over the years have investigated the effects of chewing gum on appetite and hunger, finding that chewing gum seems to reduce subjective appetite and reduce snack energy intake.^[41][42][43] One study even found that it reduced hunger by increasing satiety.^[44]

Gum chewing might trick your brain into (sort of) thinking you’re eating. It increases the levels of an intestinal hormone called GLP-1, which is involved in producing the feeling of satiety.^[45]

Chewing gum may reduce energy intake from snacking, and may reduce hunger levels.

Headaches and TMJ

While chewing gum might provide some interesting benefits, it doesn’t come without potential detriments: in certain people, chewing gum seems to worsen headaches, and a few studies have found associations between gum chewing frequency and headache frequency.^[46][47]

Excessive gum chewing also is correlated with worse TMJ (temporomandibular joint) symptoms,^[48] and TMJ problems can be headache triggers.^[49]

If you’re prone to tension or migraine headaches, or TMJ issues, you might want to avoid excessive gum chewing.

The bottom line

Gum chewing is somewhat akin to drinking coffee. It's a common habit that has mixed evidence, with a decent number of studies showing potential benefit, and just a few suggesting potential for harm. Remember that the dose is important here: excessive gum chewing is much more likely to cause problems than occasional chewing. If you find that gum chewing helps lower your appetite, or improve your anxiety or oral health... chew away!