Doctor's Note

That was a long one! Normally I’d split this information up across a few videos into a series, but I didn’t want to leave people hanging. And, I figure this is easier to share with friends and family if it’s all packaged into one video. Well, almost all—for other aspects of oral health, check out my video Plant-Based Diets: Oral Health.

What’s so great about citrus? I’ve got a bunch of interesting videos coming down the pike, but here are a few current ones that hint at the benefits:

Anything else people eating healthy diets should be aware of? The most important consideration is vitamin B12. See my blog posts Vitamin B12: how much, how often? and Vegan B12 deficiency: putting it into perspective.

I imagine there are those not happy with my mention of the F-word, but I am not convinced by the concerns that have been raised about fluoride (see my Ask the Doctor entry The dangers of fluoride (tap water fluoridation)?)—though it may be possible to get too much in tea, especially for children (see my video Overdosing on Tea).

Also, be sure to check out my associated blog posts for further context: Do Vegans Get More Cavities? and Hibiscus Tea: The Best Beverage?

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  • David Cooley

    Dr Greger – I have always felt and your video seems to confirm this, that drinking water after eating is beneficial, especially if its alkaline water, which is what I drink. I dont think there are any studies that specifically show that alkaline water reduces the risk of cavities, but from your video today, I suppose one could conclude that it would.

    Drinking alkaline water throughout the day, and even when waking in the night, taking a drink of alkaline water may decrease any acidity buildup.

    Thank you for your continued daily informational tidbits.

    • Thea

      David: If you haven’t seen it already: You might find Dr. Greger’s video that is specifically on the topic of alkaline water to be very interesting.

      • bouldercreeker

        Could someone help clarify? I drink unsweetened mild lemon water throughout the day; I love how it tastes and heard it was good for me. I’ve heard that the acid in lemons ends up having an alkalinizing effect. Should I be using baking soda in my water instead?

        • Jeff K

          I think it depends how much lemon you add to your water. If it reduces its pH to 5.5 or less, then you’re adding too much. That’s the point where cavities start forming. You can buy some pH test strips either on-line or at some health food stores to find out if you’re adding an appropriate amount. It might take a bit to get used to the taste of baking soda in water.

          • ted

            I added the least amount of lemon juice to tap water that I could without using any special equipment (I’m guessing about 4 drops of lemon juice to 12 oz tap water) and the pH dropped from 6 to 5. I repeated the first step once again and the pH dropped from 5 to 4.
            It would be pretty difficult to add any appreciable amount of lemon juice to (unbuffered) water without the pH dropping lower than 5.5.

        • ted

          Instead of adding baking soda to your water, I would suggest drinking your lemon water through a straw. I drank lemon water for more than a year–using a straw–and the dentist never mentioned noticing any accelerated enamel erosion. I also rinsed with regular water, if I thought I got some lemon water on my teeth.
          I personally wouldn’t just add baking soda to my water. Since lemon juice (very acidic) is apparently alkalizing for the body, (odd, I know), then maybe baking soda has an acidic effect on the body. Plus, your stomach pH can range from 1 to 5 acidic) depending on whether or not you are digesting food. The low pH is necessary for initial breakdown of proteins. Perhaps slurping a baking soda solution throughout the day would affect your efficiency of digesting proteins.

          • Alex

            “Since lemon juice (very acidic) is apparently alkalizing for the body, (odd, I know)”

            Odd and doubtful. An acid would be “alkalizing for the body” if some other process were involved like, oh I don’t know, decalcification?! From where does this idea comes from?

  • Varda

    From this data it seems that brushing is promoting teeth erosion???

    • b00mer

      Not brushing per se; when you eat acidic foods, your enamel becomes softened for a period of time. It is brushing while your enamel is in this “softened state” that the erosion occurs. Giving your enamel time to harden back up before brushing will help to prevent the erosion. I have also seen the advice that if you do need to brush right away, rinsing with a baking soda solution prior to brushing may help. You do not want to stop brushing altogether! The bacterial buildup that would ensue would result in a lot more erosion.

  • Ed1618

    I’ve found rinsing with a dilute solution of baking soda (1/2 tsp in a cup of water) after eating foods – oranges, or even salads with a lemon juice based dressing, as extremely effective in reducing and even eliminating tooth sensitivity, both in the short and long term. Certainly it’s worked far better than any dental product I’ve tried, many of which seem both toxic and ineffective. I’d bet a dilute solution of baking soda works a lot better than rinsing with plain water, as it will neutralize any acids, even those in relatively inaccessible areas, almost instantaneously.

    • Jordan Bray

      Lovely! I’m going to give a baking soda rinse a try… This video for me was long-awaited because I want to take great care of my teeth, but they do feel slightly more sensitive after going vegan.

      Also, I’m curious which herbal teas may cause dental erosion. Anybody have some info on this?

  • Dr. Ze’ev Gross

    Dr. Greger – I am a vegan Family Physician (Edmonton, Canada) and take the opportunity to thank you for your comprehensiveness and dedication in sharing essential nutritional facts. I was inspired by you, as well as some other remarkable physicians (e.g. late Dr. David Servan- Schreiber) and provide free nutritional and healthy life style lectures. Evidenced-based knowledge about healthy life style is indeed one of the majo tools for preventative medicine in which nutrition plays the dominant role.

    As for Oral Hygiene – I’d recommend to mouthwash with alkaline water (cup of water with a pinch of baking soda – lasts for the whole day) after every meal. Teeth brush with a gently teeth paste (containing fluoride), flossing and rinsing with Listerine mouthwash before bed time.

    In light of your last video – can you comment on that?

    Specifically, what are the potential benefits and possible harms in using baking soda and Listerine?

    Thank you in the name of many who cherish your work.

    • Mack

      I tested Listerine with pH paper and found it to be acidic. I wouldn’t use it, but your baking soda idea sounds great

    • hmm

      fluoride is toxic…

      • Dr Cingel

        Chloride is toxic too! And you put it on your food… as Sodium Chloride. Fluoride treatment is usually in the form of sodium fluoride. Remember salt can kill you as well as drinking too much water. Is water poison?

        • Joe

          Comparing fluoride to chloride isn’t so helpful. They have different properties and act differently in the body.

        • AC

          Is arsenic not poison because too much water can kill you? 5 grams of sodium fluoride will kill you. Will five grams of sodium chloride kill you? You’re a doctor…I would have expected a MUCH better argument from you.

          • Bernard

            Actually, sodium fluoride’s toxicity is rated at 52mg/kg. So 5.2g will have a 50% chance of killing a 100kg person. However, we don’t consume that much.

            Capsaicin’s LD50 is actually lower than sodium fluoride. 4.7g is enough to cause a 50% chance of death in a 100kg person.

            The point is that just because something is toxic in certain doses doesn’t mean it’s toxic in other doses. There are 4.0mg of sodium fluoride in a liter of drinking water. A 100kg person would have to drink about 1300 liters of water before risking poisoning.

            Also, if the fluoride in water were as toxic as you fear, then we would see more fluoride related deaths.

          • Pedecia

            You don’t see the deaths because it kills you slowly. That is the main reason has been added to the water in the first place. Depopulation. There are several videos on youtube done by very respectful people that will help you to understand. Gerson for Cancer Patients don’t even recommend to shower on normal fluoridated water think about drinking it. It has been shown also from many studies to low the immune system.

          • Bud

            Depopulation??? The Democrat sponsored immigration laws of 1990 now bring about 3 million immigrants into the US each year, including those with AIDS, since AIDS was specifically removed as a disqualifying factor for applicants. If it’s a conspiracy to depopulate, it’s all about depopulating the race that founded the entire damned country. To hell with Democrats.

    • Just curious why you think fluoride is necessary when so many studies suggest not? Also why do you think people should use Listerine? I don’t feel it is necessary for good oral hygiene. If you have a good diet and floss and brush (with non fluoride toothpaste!) you don’t need some chemical mouthwash! I also use to be a dental assistant and although most dentists push fluoride, (probably cause they make a lot of money doing treatments) I prefer not to use it and tell our dental office not to use it on my children and husband! Can’t believe they used it on my husband last time and he has fluorosis!!!

    • Check out this video from a few months back:

      Don’t Use Antiseptic Mouthwash

    • Dan Lundeen

      The problem with listerine is that it kills the beneficial oral flora, see

  • Nunya Biznez

    My dentist always comments on how my teeth are in the top 1% :-) I’ve had a high fruit diet for 20 years. Yes I can notice that my teeth are more sensitive after citrus though. But I avoid brushing them after citrus like the video says :-)

    Dr Greger, keep researching fluoride. There’s a BIG difference between Calcium Fluoride and Sodium Fluoride. Sodium Fluoride is some scary stuff. I’ve always avoided it and have perfect teeth. Unfortunately, recently, my city added it to the water and, although I don’t drink it or use fluoridated toothpaste (only shower in it), I’ve noticed a little Dental Fluorosis (white flecks on my teeth in my case) in the morning. Luckily due to the reduced levels of Fluoride in my system, it fades during the morning, but now I see many people with severe white flecks on their teeth. Something I never saw before the Fluoride was added. I’ve watched documentaries on the stuff. Scary.

    • ted

      There are many misconceptions about fluoride. Fluoride is not necessarily toxic. It depends on the concentration. The drinking water in Denver, CO, for example, contains naturally-occurring fluoride very close to the levels that are recommended for drinking water fluoridation (0.7 mg/L to 0.9 mg/L). The water company (Denver Water) actually removes some fluoride when the naturally-occurring levels exceed the recommended levels. This water comes from the Platte River which is used by many other cities on down the line. This water supply has been used by millions of people over 100’s of years without problems related to fluoride.
      I find that the public’s perspective is that the government adds all of
      this fluoride to all of the drinking water. That’s simply not true. The communities that add it are using a target value that’s very close to a natural concentration of fluoride, just not the natural concentration in their particular water supply.

      • Joe

        Yes, but they’re not adding natural fluoride are they? They’re adding hexafluorosilicic acid from China. A dirty byproduct from the fertilizer industry contaminated all sorts of wonderful things.

        Why add it to the water anyway when it is in the toothpaste? Study after study has shown that topical application is all that is needed, and internal application is an unnecessary risk.

        The biggest misconception about fluoride is the misconception that adding a pharmaceutical product to the water supply is the best method for giving the correct dose to a public that hasn’t even given their consent.

  • guest

    Very important to note that the study does not specify if the fruit juice was; fresh pasteurized, or fresh concentrated juice. Though these two should not be confused with fresh squeezed straight from a juicer. All three types are different and have different effects on the body. It is well known that concentrated fruit juice ravages teeth much like sugar (highly acidic).

    Fluoride is toxic, and is usually coupled with SUGAR, dyes, pork fat, among other substances in regular toothpaste and should not be consumed or used. Fluoride toothpaste comes with a warning in the usa as its a poison.

    • ted

      The warning about fluoride is so you don’t swallow the toothpaste which can be highly concentrated in fluoride. Simply passing it over your teeth then spitting it out won’t hurt you.

      • Pedecia

        Wrong again. It gets absorbed by the oral cavity. The oral cavity is the first line of nutrients absorption and definitely can absorb fluoride. Why all this push on fluoride when there is not a single study that shows it helps teeth?? Because the Lying government told you so? Fluoride has been used by governments like was used by Hitler. Go and research on the Illuminati Agenda and the New World Order… People do not use Fluoride, do not drink fluoridated water and do not use Toothpaste with Fluoride. Private clinics and Hospitals that cures Cancer Naturally do not even let patients shower in fluoridated water as it gets absorbed and lowers the immune system.

        • Thea

          Lt. Nimitz/Pedecia: Did you know that many natural streams/water have fluoride in them? And that fluoride is one of the main substances our bones are made out of. When governments attempt to add fluoride to drinking water, the goal is to add enough fluoride to match that found naturally in normal/untreated water.
          I’m not trying to make the argument that fluoridating our drinking water is good. (I don’t know one way or another. I think the issue is complicated.) My goal is to provide some balance to the picture as posts such as yours paint fluoride as being a poison and all bad. Clearly that’s a misunderstanding about nature and our biology.
          If you are interested, you can learn more about this topic and bone health in general from the book: Building Bone Vitality:–Without/dp/0071600191/ref=sr_1_1_twi_pap_1?ie=UTF8&qid=1466355009&sr=8-1&keywords=building+bone+vitality

  • beccadoggie10

    For the first time in decades, I had zero cavities at my last checkup. Perhaps, it is because I’ve been eating vegan and avoiding wheat as a way to reduce pain and inflammation.

    As for brushing, my dentist and periodontist said it’s not as important to use a fluoride tooth paste as it is to brush, even with plain or filtered water twice a day with flossing and brushing at night. This works! But, diet is also critical and eating healthy vegan has worked for me.

  • beetsbeansbutts

    Thanks Dr. Greger! This was very informative.

  • Lisa

    Kangen water also will balance ph as it is alkaline. Please look at Let me know if you have any questions.

  • J

    Would drinking through a straw help?

    • Kaen

      I also wonder if straw drinking would decrease the negative effect. Are there any comparative studies on dental effects from straw vs non-straw drinking of fruit juice/smoothies?

    • LynnCS

      I’ve always thought it was funny that some people think that if they drink something through a straw, that it wouldn’t get on their teeth. It’s just impossible.

      • Nicola

        actually he had a video out today that shows that straw use does REDUCE erosion caused by acids. Yes of course it does not eliminate it from touching your teeth at all, but it is limited by using the straw. And if you use straws, glass straws are the best for you and the environment. They are reusable (clean with pipe cleaner type brush) and they come with a lifetime warranty against breakage.
        Here is a link to the video on his YouTube channel. Part about the straw use I believe was around the five minute mark

    • James

      My dentist says yes. If the straw is shoved all the way to the back and you take short sips and short swallows, you can avoid the teeth entirely, but this is difficult to achieve and becomes tiresome very fast. If done correctly, you will not taste much. Taking bigger sips/gulps is easier but you will get the rear of the back molars exposed. Even if the teeth are avoided completely, some acids can remain on the tongue and make their way back to the teeth via saliva, which is why the water rinse immediately afterwards will help but make sure you swallow the water, as opposed to spitting.

  • Miles Roberts

    What an incredible resource you are. Thank you very much for your great work. In your presentation regarding “Plant based diets and oral health” coffee was not mentioned. Where might coffee stack up when compared to fruit juice, or soda in terms of it’s erosive potential?

    • Mike Quinoa

      I believe coffee is fairly acidic. I add a little salt to my coffee to help neutralize the pH.

  • leet

    Should be important to note that a poor diet is associated with high risk of cavities vs a healthy diet has been shown to prevent and sometimes reverse cavities.

    • melanie

      I have never heard that reversal of cavities was possible. My dentist denies that, but it goes against the principle of the body trying to heal itself. Do you have a source for this? Thanks.

      • Thea

        melanie: I can’t provide you with a source, but I can repeat what my dentist told me. He said that they used to think that once a cavity formed, there was nothing that could be done about it. But now they have evidence that small cavities at least can be reversed. However, I was not given a site/source for this information. He also did not seem to know if we know what conditions need to be in order for cavities to reverse. I’m sharing this with you so that you know at least one other person has heard this same type of news.

        I think it is really exciting and wish they would do a lot more research on it.

  • SnarkyVegan

    So if we follow the logic presented in the studies, should I NOT drink coffee/tea/wine right AFTER as well as BEFORE brushing my teeth? Seems like the dentin would be more easily stained or otherwise damaged either way.

  • banat masr
  • melanie

    I remember in the 90s, in Victoria, BC (Canada), there was a campaign to encourage people to eat cheese after a meal, claiming it helped reduce cavities. Or perhaps it was an apple and cheese. Looking back at it now, it seems like a bizarre recommendation, and I question what science was behind it and who funded it. It certainly hasn’t lasted the test of time.

  • Delisa

    I’ve personally experienced this problem with my teeth. After eating a vegan diet high in fruits and veggies for 20 years, I began to get cavities that resulted from the loss of tooth enamel. I’m glad you’re reporting on this here. I like to use a Water Pik to rinse my mouth after eating, but now I know to wait awhile before brushing. I was doing that wrong!

  • Cynthia

    On page 169 in Dr. McDougall’s book, the Starch Solution, he says:”the methylcobalamin and hydroxycobalamin forms of B12 are better choices.” I respect both of you and would like clarification. Thank you

    • I was given this same rec in the T Colin Campbell/eCornell Plant-Based Nutrition course.

  • Dr Antony Tam

    Chinese Taoist tradition use making of saliva enough to swallow loudly and at least 3 times with tongue tip to the anterior palate to promote health of the “kidney system” ( one of the 5 that include every parts and tissue of the whole body) that includes and support the bone, whose outward (glory) sign is the teeth; the the brain and all the nerves. Saliva is alkaline, has substances for immune defence, enzyme for digestion, neutralise toxins, has 27 names down the 2000+ yrs of history ,describing it in the Chinese health and Taoist literature–showed its significance.
    There are popular Chinese exercises described, to make more saliva, if it does not flow naturally–by swirling one’s tongue over all the surfaces of teeth, naming
    “red dragon (tongue)churning the sea (of saliva)”

    Dr Gregor , is there studies about the caries preventing effects of saliva?

    • LynnCS

      My old dentist told me that keeping your saliva healthy was the most important think for your teeth. He advised eating meat and no starches. Haha! He tried. Never said anything about alkalinity, but I soon got into Macrobiotics and learned about it there. It takes a lot to figure this thing out. Thank you Dr.Greger for your posts.

  • 12tanks

    I thought fluoride was a toxic poison and produced no beneficial effects on oral health.

  • 12tanks

    Fluoride in drinking water and toothpaste is poison! There’s all kinds of documentaries, studies and evidence that support my statement.

  • Lyn-doe

    Why would they encourage fluoride? Fluoride is bad for you. Wild animals do not brush their teeth and have no problem with dental hygiene. What about all of Weston Price’s work showing that native cultures eating their native diets had almost no incidence of dental problems. Most of them didnt practice what modern day considers good oral hygiene. I think when you brush your teeth, especially if you use a standard tooth paste, it disrupts the natural mouth flora.

    • Thea


      Some thoughts for you:

      1) Wild animals do not eat the types of unnatural foods that humans today eat

      2) Dogs, who tend to eat the processed types of foods that humans now eat, do have dental problems.

      3) “native cultures” would not have been eating candy bars and chips and TV dinners, etc. Thus, it would make sense that they would not have dental issues just like wild animal’s teeth seem to do pretty well – at least during their relatively short lifetimes.

      4) given that modern human eating habits do lead to dental problems, using having a substance that is clinically proven to prevent dental problems sounds like a good thing to me.

      5) Health information or guidance from the Weston Price foundation/website is of highly questionable value. I refer you to the scholarly work posted called Primitive Nutrition on YouTube if you want to learn about the weaknesses of the information given on the Weston Price Foundation site. Plant Positive covers much more than just Weston Price, but you can search until you find the Weston Price material (again, only if you are interested of course).

      Good luck to you.

      • Thea

        Ah, found it. While I highly recommend the entire series, it is Primitive Nutrition 26, where you can learn what you need to know to put the information that the Weston Price foundation gives out into perspective.

      • Thea

        Well dang, I don’t know where that picture above came from. I didn’t put it in and I can’t figure out how to get it out. If anyone wants to check out the Primitive Nutrition series of videos, I recommend clicking on my link, not the picture of the video that seems to be attached to my post.

    • Roberta Peck

      When visiting Anasazi Indian cliff dwelling ruins like Chaco Canyon,it was amazing to discover the poor dental health on skeletal remains which was attributed to grinding corn on sandstone. There are always various factors which impacted various native populations, but certainly a lack of refined sugars and grains was a common denominator, in the study you point out.

  • Friend

    Can tooth decay be reversed by diet?

  • Rand

    Appreciate the abundant relating of how increasing plants in diets is strongly helpful and healthful. However, in one footnote the use of fluoride toothpaste is advised. Use of fluoride has now been rejected by the Canadian Dental Assoc. and by most European Dental Associations as being a risk/hazard to long term health with little or no consistent benefit to dental health. Fluoride is a severe toxin, hazardous waste from chemical production. If fluoride producers could not sell it to toothpaste manufacturers, they would instead have great expense in securing safe disposal of this very hazardous, toxic chemical waste.
    Research it. Fluoride is extremely hazardous, harmful, toxic and has no credible benefit to oral health.

  • John

    Dr. Greger:

    Can you do a video on enamel remineralization? I eat A LOT of fruit and I am worried that it is keeping my oral pH too low and dissolving my enamel, even though the rest of my body and mind is loving it.

    Also, there is a book on amazon about remineralization and it says you need a diet high in oil and fat soluble vitamins (A, D, K) the only problem is that the diet it recommends is predominately non-vegan. BUT, people who have done the diet have COMPLETELY fixed giant black caries in their teeth! That’s crazy! Even though they did it by eating animals, it seems to be on the right track for what is necessary to remineralize enamel.

    Thanks for being totally awesome!

    • dogulas

      That’s pretty interesting. Care to link to the book page, or give the title?
      Seems like a fluoride rinse is the best option at the moment, that I’m aware of.

    • Bob Dorris

      I’d love to hear more on dental remineralization with a vegan diets, as well.

  • Chez

    My dentist suggested that we eat more dark green leafy veggies to help re-calcify our teeth. I asked whether chewing the greens before eating would be more beneficial than just eating them (smoothies, juice, cooked, etc). Can you get any calcium out of the greens and into your teeth through mastication? I want to get your take on it. Thanks.

  • Jeff and Karen Hay

    Aloha NutritionFacts,

    Have you ever heard of an Ayurvedic practice known as “oil pulling” whereby one pushes and pulls oil (usually coconut oil) back and forth through ones teeth and gums for 20-30 minutes which allegedly removes a great deal of bacteria?

  • Maree Chambers

    Having had a heartattack and nervous about antibacterial mouth washes. I would like to know what I can use because at the moment I have a small swelling on one side of my mouth palate. I have been using warm sea salt water. Also drinking the South African Rooibos (redbush) tea with fresh lemon juice and organic honey.
    I was told that combination of Tumeric and honey taken into the mouth would help heal my palate.
    Chlorhesidine Glutonate seems very bad for heart patients.

  • Katherine T M

    I’ve been vegan about 1 year and I never had cavities (caries) in my whole life. Yesterday I saw a small cavity in one of my molar tooth and I feel very upset. I started thinking about something that has changed in my routine because I don’t believe that is something wrong with my diet. (I always had a good diet with lots of plant based food, no much sugar and regularly brush my teeth.)
    So, I moved to the UK a year ago and I’ve stopped to drink water with fluorite (I’m from Brazil and they artificially fluoridate the water) and also haven’t been using toothpaste with fluorite since I moved.
    However, I’d like to discuss about the uses of fluorite for health. Because many people say that it’s terrible for your health, but I guess the problem is how much you are exposed (inside your body) by fluoride (ej drinking fluoridate water), not in the toothpaste. (water fluoridation in the UK:
    Now I started to look for vegan toothpastes with fluorite (for treatment and prevention) but it’s so hard to find. Why do some vegan people avoid products with fluoride? And why don’t the UK fluoridate the water?
    Obs: Vegan Brazilians also are against the widespread use of fluoride. I read some articles about cancer(?) and fluorosis (yes, this can be happen). But I agree with the NHS article bellow (
    Please, share your knowledge and experience with me. Thank you

    • Thea

      Katherine T M: I’m sorry to hear you have developed a cavity. Regarding some of your questions: I don’t have any data to back up my guess, but I’ll share it just the same. While I think the benefits and harms of consuming fluoride in water are unclear, I haven’t seen any data showing that just brushing with a fluoride based toothpaste is harmful. Seems to me that at a minimum, you would want to get a good toothpaste. You could even look into prescription strength toothpaste.
      I’ll also state that Dr. Greger does not share my doubt/concerns over water fluoridation.
      Good luck!