Rinsing with Green Tea Improves Oral Health

Rinse with green tea and keep your teeth happy. (Photo by Daria)

I've written before about the protective effects of green tea against dental caries. Several studies have shown that green tea helps tooth and gum health by reducing harmful bacteria, increasing enamel strength and inhibiting the breakdown of starch to sugar.

Black tea, cocoa and coffee protect against oral problems too, but green tea seems to be the most effective. A new study sheds more light on how drinking green tea improve oral defense mechanisms through oral peroxidases (OPOs) (link).

The two major defensive peroxidases of the mouth are salivary peroxidase (SPO) and myeloperoxidase (MPO). Their function depends partly on diet and probably also on genes.
In the abstract of the paper, the authors mention that their earlier study showed that elderly people who drank green tea for 3 months had higher levels of oral peroxidase activity than non-drinkers. In this study, they compared the effects of green tea on OPO in vivo and in vitro.

Adding a green tea infusion to saliva increased oral peroxidase activity by 280%, while black tea increased it by only 54%. Adding only epigallocatechin gallate (EGCG), the main polyphenol in green tea, increased activity by 42%. The effect was dose-dependent, which I assume here means that the stronger the tea, the greater the effect.

In human subjects, green tea gave a very similar result. Mouth rinsing with a green tea infusion resulted in a 268% increase in OPO activity. Thus, while green tea extracts may be more useful than just drinking regular green tea for some purposes, for dental health drinking and/or rinsing is probably the most effective way.

Note, however, that higher levels of salivary peroxidase don't necessarily mean better oral health; in fact, people with more dental caries and gingivitis tend to have higher SPO activity (link). My guess is that this is a defense mechanism against the harmful effects of excess hydrogen peroxide, which is excreted by oral bacteria. In other words, the stronger the attack, the stronger the defense.

In the case of green tea it seems that increasing SPO really does lead to better oral health, though.

For more information on green tea and dental health, see these posts:

Drinking 10 Cups of Green Tea Daily and Not Smoking Could Add 12 Years to Your Life
Green Tea Extract Enhances Abdominal Fat Loss from Exercise
Vegetable vs. Animal Sources of Vitamin A: Why Eating Carrots Isn't Enough
Genes, Diet and Oral Health: Why Do Some People Get Cavities and Others Don't?

Vegetable vs. Animal Sources of Vitamin A: Why Eating Carrots Isn't Enough

Think you're getting enough vitamin A from carrots? Think again. (Photo by Ben Hussman)

In the comment section of my previous post on genes, diet and cavities, a couple of readers commented that vitamin A is necessary for proper dental health. I replied that I get plenty of beta-carotene (the vitamin A precursor found in vegetables and fruits) from red palm oil, which I use for most of my cooking these days.

Today, however, I came across a couple of papers looking at how well humans actually absorb beta-carotene and convert it to vitamin A (link, link). To my surprise, the conversion rate was much poorer than I'd previously thought. The first paper, which looked at beta-carotene absorption in 11 men, had this to say:

The vitamin A activity of ß-carotene is variable. The carotene in fruit, grains, and oils seems to be more effective as a source of vitamin A than that in dark-green leafy vegetables.

So, not all sources of beta-carotene are equally good in terms of absorption. The conversion rate also depends on the amount of beta-carotene (the higher the amount, the lower the rate) and whether fat is included or not.

Strikingly, only 6 of the 11 men included in the study absorbed and converted the beta-carotene they were given. The remaining 5 were classified as non-responders. The authors conclude that the vitamin A activity of beta-carotene can be "surprisingly low and variable". Even in those who did respond to supplementation, mean absorption was only ~4% and the conversion ratio was ~0.05.

In a similar study on 11 women, the same thing happened: only 6 of the women absorbed and converted beta-carotene enough to be measurable, while 5 women were non-responders. In those who did respond, mean absorption was ~6% and the conversion ratio ~0.1. This confirms earlier findings reporting that women absorb and convert beta-carotene more efficiently than men; the same also appears to be true in rats.

These figures suggest that the commonly accepted conversion rates of beta-carotene from plant sources may be too optimistic. Even red palm oil might not be up to par with animal sources. In one study, switching from green leafy vegetables to red palm oil did increase retinol levels, but only in subjects who were vitamin A deficient to begin with (link). And for many Westerners who don't eat palm oil or organ meats, the reality is even worse:

Also, it seems that the vitamin A activity of ß-carotene that is not dissolved in oil and emulsified is low and variable. Most ß-carotene in the American diet is not consumed in an emulsified form with fat. Our intent was to replicate a typical diet to develop better leads for how the body utilizes its given resources. The fat content of the meal that accompanied the doses in our study was the recommended amount, 30%. Many professionals recommend lower-fat diets.

Now there's something for the low-fat raw food vegetarians to chew on. On the other hand, the absorption of retinol, found in animal sources such as liver and eggs, appears to be much higher. Most of the estimates I've seen on various websites are between 60-90%, but even that may be too conservative, as the only actual study I could find showed that absorption was >99% (link).

Since my vitamin D levels are already good, and I take vitamin K2 supplements, the missing link in the trinity of dental health could indeed be vitamin A in my case. While I do eat eggs every now and then, their retinol content is only about 10% of that of liver. I guess it's time to put organs on the menu.

For more information dental health, see these posts:

Genes, Diet and Oral Health: Why Do Some People Get Cavities and Others Don't?
Tea, Coffee and Cocoa: All Good for Your Teeth
Dental Health Effects of Green and Black Tea
Preventing Mouth Ulcers with Tea Tree Oil Toothpaste - Results after Two Months

Genes, Diet and Oral Health: Why Do Some People Get Cavities and Others Don't?

Getting rid of candies didn't prevent me from getting caries. (Photo by exper)

As you may know, I have something of an ongoing experiment with dental health. This includes reducing cavities, preventing gingivitis and the receding of gums, and also finding safe ways of whitening teeth.

In previous updates, the main focus has been on the teeth whitening aspect. The last product I purchased was called "Plus White 5 Minute Bleach Whitening Gel". Compared to the supposedly teeth whitening toothpastes out there, this product does seem more effective.

However, in recent months, I've noticed increased sensitivity along the gumline. Specifically, the gums next to two of my upper teeth seem to be the problem. The whitening gel probably has very little to do with it, but it doesn't solve the problem either. In the short term, whitening gels can increase sensitivity, so for the time being, I've turned my focus elsewhere – to preventing caries and improving gum health.

The motivation for this post is that I've struggled with these things my whole life, and despite my various experiments with diet, I've yet to find a proper solution to the problem. When I was a kid, the common explanation was that too much candy and soda was the reason for dental cavities – despite the fact that scientists had already shown that carbohydrates in general give rise to the bacteria that cause caries. So when I got a bit older, I cut back on candy and soda, hoping it would be enough.

Unfortunately, it wasn't. Apart from the Snickers Bars and Coca-Cola I'd occasionally enjoyed that were now gone, my diet remained the same. It took me a long time to discover that all carbs are essentially sugars, that all acidic drinks make the issue worse, and that it's not just Coke and candy that are the problem. You can get cavities just as easily by eating bread and drinking apple juice. Then it was time to get rid of those too.

When I reduced my carb consumption and switched to a more paleo-like diet, my dental health improved, but it still didn't stop me from getting a new cavity every now and then. Furthermore, I knew several people who ate junk food and drank acidic sodas all the time, and yet had never had cavities. Some didn't even brush their teeth every day, let alone floss. When we were kids, my brother and I had very similar diets, and yet I was the only one to get cavities.

These things have led me to believe that genes play a more important part than most dentists would have you believe. Kind of like some people stay thin no matter how much they eat. But, just like in the case of weight loss, your genes do not necessarily determine your fate – it just means you have to know what you're doing. People who don't have the genes for staying naturally thin have to be more careful with what they eat if they want to avoid weight gain. Similarly, people who get cavities easily have to be more careful with dental health.

While keeping your teeth clean by brushing, flossing and chewing gum prevents cavities, I'm wondering whether all the cleaning really strikes the problem at the root (no pun intended). If genetics do play a role, what is it specifically about some people's genes that keeps them from getting cavities, despite their poor dental health habits?

One important factor in cavity formation is saliva. The surfaces of teeth are constantly going through a process of demineralization and remineralization. The balance depends, in part, on salivary flow and the pH of saliva, with the mineral content probably playing a role as well. I know my mouth often feels kind of dry and acidic, which can't be a good thing for remineralization. What is unclear to me is how to affect these things.

There are a million websites out there listing foods that are "acid-forming" or "alkaline-forming", but the classification seems very unscientific. Some list apples as acid-forming because apples themselves are acidic, some list them as alkaline-forming because they claim we should look at what happens after digestion. Here's a quote from one such website:

All foods are "burned" in the body -- more commonly called "digested" -- leaving an ash as the result of the "burning", or the digestion. This food ash can be neutral, acid or alkaline, depending largely on the mineral composition of the foods.

I'm not sure how scientifically valid this theory is in the first place, but I do know that even those who promote the "food ash" theory disagree on which foods leave acid or alkaline ash. One person will tell you plums are acid-forming, while others will tell you they're alkaline-forming. I doubt any of them have actually burned plums and studied the ashes.

So, expect some dental health related posts in the upcoming weeks and months, as I go through some of the papers on the subject. I'm also interested in hearing your comments, especially if you've previously suffered from cavities but managed to find a solution.

Meanwhile, for more information on dental health, see these posts:

Tea, Coffee and Cocoa: All Good for Your Teeth
Dental Health Effects of Green and Black Tea
The Role of Coenzyme Q10 in Oral Health
Whitening Teeth & Healing Gums: In Search of the Perfect Toothpaste

Teeth Whitening Experiment: Plus White 5 Minute Bleach Whitening Gel

Do vampires dream of electric teeth?

It's been about three months since my last update on the teeth whitening experiment. This experiment is my attempt to find safe ways to whiten my teeth and keep gums from receding. Given that I drink copious amounts of green tea and coffee daily, the whitening part has proven rather challenging.

For those who haven't been following the blog for very long, here's a quick recap. The first toothpaste I tried was Beverly Hills Formula Natural White, which I found in a grocery store while abroad. On paper, this toothpaste had all the good stuff – including coenzyme Q10 and green tea extract – but I didn't really see any real results. For the next few months I turned to Colgate Sensation White with its "micro-cleaning crystals". Again, no visible whitening of the teeth.

After Colgate it was time to try an ordinary store brand. The product I tried contained a combination of hydrated silica and triglycerides, which were supposed to work together to remove plaque and whiten the teeth. Granted, my teeth didn't get any more discolored despite all that tea, coffee, dark chocolate, and turmeric, but still, they didn't get any whiter either.

So now, after discovering that none of these whitening toothpastes seem to have any real whitening effect, I've brought out the big guns. Or at least slightly bigger than those pathetic toothpastes. This product is called Plus White 5 Minute Bleach Whitening Gel (for sensitive teeth), which is not a toothpaste per se but a gel that you leave on the teeth for a few minutes.

The whitening effect of this gel is based on hydrogen peroxide, a common ingredient in DIY teeth whitening products, and best of all, a substance actually proven to whiten teeth. You could probably make a very similar gel at home if you got your hands on some hydrogen peroxide, but I took the easy way and ordered the product online (since they don't sell Plus White in Europe, at least not in Finland). With international shipping it was a bit costly, but if you live in the US, you can get this stuff for a few dollars in several retail stores.

The instructions say to apply the gel on the teeth twice a day and leave it on for five minutes. After two weeks of use, you can start applying it less often. I'm going to start by applying it once a day to track any possible whitening effects more carefully. I'll probably be too lazy to take pictures, though, as it's a hassle to get the lighting right to make any worthwhile comparisons of tooth color. But rest assured, once I see results (or once I run out of the stuff), you'll be the first to know.

I have to say this is the first teeth whitening product that I actually expect to work. But then, I've seen absolutely no effect from so many supplements I've experimented with that I won't be too surprised if it doesn't. I'm just worried that if this doesn't work, the next step is going be an expensive visit to the dentist.

For more information on oral health, see these posts:

Tea, Coffee and Cocoa: All Good for Your Teeth
Dental Health Effects of Green and Black Tea
The Role of Coenzyme Q10 in Oral Health
Preventing Mouth Ulcers with Tea Tree Oil Toothpaste - Results after Two Months

Whitening Teeth & Healing Gums – Experiment Update: Colgate Sensation White

The search for the perfect teeth whitening toothpaste continues. (Photo by jet platypus)

It's time for another update on my teeth whitening & gum healing experiment, which has been going on for quite a while now. As you may have guessed, the idea behind the experiment is to find safe and easy ways to whiten teeth and stop gums from receding.

To recap, for the past months I've been brushing my teeth with Colgate's Sensation White. This toothpaste has something called "micro-cleaning crystals", which are supposed to get rid of stains from coffee, tea, etc. According to Colgate, regular use will have a whitening effect in general. As a sign of confidence, the toothpaste even comes with a color strip to compare your teeth against.

I thought the included color strip was a great idea, but in practice, it's surprisingly difficult to find an exact match for your teeth color. So I decided to just rely on visual inspection. Subjective as it may be, I can say with a fair amount of certainty that my teeth are no whiter than they were before using Colgate. In fact, I would go as far as to say that they may have gotten even more discolored during these months.

This is most likely due to the fact that I drink several cups of green tea per day. While it most likely has a smaller effect than black tea, it still stains teeth in the long run. Another culprit is coffee, which I love. None of the supposed nootropics I've tried so far give me that mood-lifting energy boost quite like coffee does.

Two cups per day is my maximum at the moment. While it's not as much as many other coffee lovers I know, it probably has a significant effect on teeth color even in these amounts. And then there's dark chocolate, possibly my favourite food in the world. Goes brilliantly with coffee, mind you. I suspect consuming a copious amount of cocoa powder each day doesn't exactly make teeth sparkle, either.

It's important to note here that while staining, coffee, tea and cocoa are all good for dental health in general. It's just that the color and health of your teeth don't necessarily go together. For me, the choice between a longer life and shiny teeth is clear. Combining both would be optimal, of course.

My trust in whitening toothpastes is waning rapidly, but nonetheless, I have chosen another product for testing. This one is an ordinary store brand toothpaste with a claimed whitening effect. According to the label, the patented whitening mechanism is based on a combination triglycerides and hydrated silica. The latter is a common compound in toothpastes, as it a mild abrasive that helps in removing plaque and apparently also whitens teeth to some degree. Triglycerides in toothpaste is a new one for me, however.

I could just stop drinking tea and coffee for the duration of the experiment, but since most people looking to whiten their teeth are probably unwilling to quit enjoying their favourite beverages, I feel the experiment is much more interesting this way. If there's a product out there that can really make teeth whiter despite near-constant bombardment with tea, coffee and chocolate, then hey, we've got it made.

And if such a product indeed exists, I intend to find it.

For more information on dental health, see these posts:

Dental Health Effects of Green and Black Tea
The Role of Coenzyme Q10 in Oral Health
Tea, Coffee and Cocoa: All Good for Your Teeth
Preventing Mouth Ulcers with Tea Tree Oil Toothpaste - Results after Two Months

Tea, Coffee and Cocoa: All Good for Your Teeth

The caffeine in coffee is good for dental health. (Photo by Ballistik Coffee Boy)

It may not come as a big surprise to you that green tea is good for dental health. After all, green tea is the miracle cure for pretty much anything, right?

If you're not a huge fan of green tea, worry not: there are other beverages out there that can do the same. In fact, if you're a long time follower of this blog, then you already know that not only green tea but also black tea helps prevent dental caries. Both are also good for the gums.

The good news doesn't stop there, however. A recent review found that in addition to tea, cocoa and coffee showed anti-cariogenic potential as well (link). The reason behind this effect is the polyphenol content in all three. Though each three has different polyphenols that work in different ways, they all appear to get the job done and improve oral health.

Cocoa and dental caries

According to the authors of the review, studies have shown that additing cocoa powder or chocolate to hamster diets reduces their caries incidence. Unsurprisingly, cocoa powder or dark chocolate works better than chocolate with high sugar and low cocoa levels. Water-soluble extracts of cocoa powder also inhibited caries formation in rats.

The two main strains of bacteria that cause caries are Streptococcus sanguinis and Streptococcus mutans. Although the case is not entirely clear, cocoa polyphenols seem to inhibit the growth of the former but not the latter.

Cocoa also reduces plaque formation by inhibiting the enzyme dextransucrase, which forms plaque extracellular polysaccharides from sucrose. In one study, a mouth-rinse made from the ground husk of cocoa beans was effective in reducing plaque scores in children.

Coffee and dental caries

Roasted coffee beans were shown in two studies to be antibacterial against S. mutans. Coffee also appears to interfere with the adsorption of S. mutans to teeth. In another study, coffee did not inhibit the growth of the bacteria, but did reduce the adherence of bacterial cells to dental surface. In other words, while coffee might not kill the bacteria, drinking coffee could prevent it from sticking to your teeth.

The compounds in coffee that are most active in terms of dental health are trigonelline, caffeine and chlorogenic acid. It is possible that the anti-adhesive effect is due to the synergistic action of these (and other) chemicals in coffee.

Tea and dental caries

Since I've already covered the topic of tea and dental health in an earlier post, I'll just go over the review findings briefly here.

Tea polyphenols appear to protect from dental caries primarily through their anti-microbial action. While cocoa and coffee are mostly effective against the adhesion of bacteria on the surface of teeth, tea in addition actually inhibits the growth of several strains of Streptococcus. The polyphenols in tea also reduce the formation of plaque, the production of acidic compounds and the synthesis of glucan from sucrose. Importantly, commercial teas have been shown to inhibit salivary amylase activity, which may significantly reduce caries formation from foods with starch.

Green tea, black tea and oolong tea (which is somewhere between the two in terms of fermentation time) have all been shown to be beneficial for oral health. Even though white tea has not been studied, it very likely has much of the same benefits as green tea. Due to its light color, it may also stain teeth less than green or black tea.

Conclusion

Tea, coffee and cocoa are all beneficial for dental health. Tea appears to be the best choice, since the polyphenols in tea are not only able to inhibit the adherence of bacteria to teeth, but also prevent the growth of cariogenic bacteria.

Tea is also effective against S. sanguinis and S. mutans, the two main strains responsible for caries, while coffee and cocoa seem to only work against the latter. While the effects of coffee have only been tested in vitro, cocoa has been shown to prevent caries formation in animals and reduce plaque in humans.

For more information on oral health, see these posts:

The Role of Coenzyme Q10 in Oral Health
Whitening Teeth & Healing Gums – Experiment Update
Dental Health Effects of Green and Black Tea
Preventing Mouth Ulcers with Tea Tree Oil Toothpaste - Results after Two Months