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Raisins and Dental Health

Raisins have a long-standing reputation as a food that promotes dental caries (cavities),” based on decades-old studies on rats that ranked raisins up there with cupcakes as among the most cavity-promoting foods. To this day, you’ll see dental authorities advise against eating dried fruit, like raisins. As I discuss in my video Do Raisins Cause Cavities?, more recent evidence—from studies done on actual people—“casts some doubt on the role of raisins with regards to tooth decay.”

The formation of cavities depends on three factors: acid, adherence (the stickiness of food to teeth), and the bacteria that make up the dental plaque. If you have kids swish some sugar water in their mouth, within five minutes, the pH of the plaque on their teeth plummets as the bacteria convert the sugar to acid. A commercial raisin bran cereal was practically just as bad. Bran flakes alone, without the raisins, weren’t as bad, however. Is that because the raisins in raisin bran cereal are crusted with sugar, though, or because of the raisins themselves? Well, raisins didn’t lead to much acid at all, and the big surprise was that if you combined the non-sugar-coated raisins with the bran flakes to create a kind of experimental raisin bran cereal, the raisins seemed to help prevent some of the acid the bran flakes were causing.

Although raisins are about 70 percent pure sugar, they caused less acid to be produced, and don’t actually appear to adhere to our teeth. Wait. Raisins do stick to our teeth, don’t they? Twenty-one foods were put to the test, and there was actually no relationship between food retention and how sticky the foods appeared to be. Bits of cookies, crackers, and potato chips actually stuck to the teeth the longest, whereas foods you’d think would stick, like caramels and raisins, disappeared within minutes. Fresh fruit like apples and bananas disappeared from the mouth almost immediately.

Phytonutrients in grapes appear to actually prevent the adherence of bacteria and prevent plaque formation, so much so that grape pomace, the by-product of wine making, is being investigated as a cavity-preventing food additive. Or, you could just drink the wine. Non-alcoholic wine inhibits the growth of the primary cavity-causing bacteria, though raisins would probably be a more appropriate snack for kids.

There’s a new test available to measure the cavity-causing activity of plaque bacteria. A pilot study was performed to see if the risk for cavities increases, decreases, or remains the same after eating raisins. They took 156 folks, swabbed their teeth, waited for the readings to get up over 1,500, which indicates high cavity-causing activity, and had half eat a little box of raisins and the other half eat nothing. In the eat-nothing control group, they started out at around 6,100 and, 15 minutes later, were still up at 6,100. The raisin group started around 5,950, but, after raisin consumption, their cavity risk score dropped down to 3,350. Although that’s a big reduction, note the score was still higher than the 1,500 cutoff, indicating they were still at risk—but the risk went down after eating raisins, not up. So, while raisins traditionally have been thought to promote tooth decay, current research suggests that raisins may not contribute to cavities after all—or at least not any more than other foods.


For more on raisins, see:

What about dried fruit in general? Check out:

To learn more about oral health, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Discuss

Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.


39 responses to “Raisins and Dental Health

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  1. I eat raisins every day, mainly for their salicylate and other phytonutrient content.
    Plus, of course, WPF diet in general, with ample, herbs, spices and green tea.
    Haven’t had a cavity in years!
    Anecdotal case of n=1, for what it’s worth.

  2. Eat a few slices of apple (or eat the whole thing) after eating and see how clean your mouth feels. Your stomach will feel better too!

  3. This is very interesting to me.

    I am pondering it because when I looked at “fruit only” diets the disadvantage listed was teeth problems and Ryan from Happy Healthy Vegan had a tooth extracted from when he was eating like that.

    Not saying it to disagree with this.

    Just trying to understand it.

    If wine / grapes is protective, it would seem like raisins might also be protective. They are partially dried grapes, right?

    The sticking to teeth part is what I was pondering during the date discussion from yesterday.

    This gives me a lot to think about.

    Wondering if there is a way to do home tests for the tooth decay risk?

    Okay, I am really confused about the teeth studies.

    Okay, I went back and looked at the don’t brush your teeth directly after eating fruit video. So that could be one issue.

    Oatmeal and grains are questions, which I am only finding the Keto perspective. Give up grains and use oils and your teeth cavities will reverse.

    I really felt like I also found studies a few years ago, where they helped the teeth lowering the blood sugar through eating grains, but if I ever did read that, I can’t get to that study through Google right now because page after page after page is anti-grain right now.

    When I was watching Mic the Vegan’s saturated fats harming the bones video, I pondered if saturated fats harm the teeth, but they are “eat oil” to help the teeth oriented and I think I found a saturated fats hurt the teeth PubMed article the day I watched that, but right now my computer is fighting against me. (Or I am remembering things in a dyslexic way?) Lets go back to the preserved teeth with no cavities you have spoken about in the past, didn’t they eat grains?

    Fat soluble vitamins help do help. Vitamin D.

    Yes, you have just generated a long research project with this.

  4. That test you mentioned measures ATP production of both good and bad bacteria.It does not tell you if you have lots of good bacteria,lots of bad bacteria or both.
    It concerns me that one uses this test for determining whether a food is more carcinogenic than others.
    Would you please site that study you discussed?

  5. Okay, I am back to the Stone Age diet one and they were eating cereal and their gums were getting better and that was helping not to erode the structure of the teeth.

    Cereal might equal oatmeal sometimes?

  6. From the PubMed link: Streptococcus Mutans, bacteria that is a primary cause of dental caries.

    So can we just find something to kill this?

    Or drink high PH water after our oatmeal?

    1. treptococcus mutans was the dominant species in many, but not all, subjects with caries. Elevated levels of S. salivarius, S. sobrinus, and S. parasanguinis were also associated with caries, especially in subjects with no or low levels of S. mutans, suggesting these species are alternative pathogens, and that multiple species may need to be targeted for interventions. Veillonella, which metabolizes lactate, was associated with caries and was highly correlated with total acid producing species. Among children without previous history of caries, Veillonella, but not S. mutans or other acid-producing species, predicted future caries. Bacterial community diversity was reduced in caries as compared to health, as many species appeared to occur at lower levels or be lost as caries advanced, including the Streptococcus mitis group, Neisseria, and Streptococcus sanguinis. This may have implications for bacterial community resilience and the restoration of oral health.

        1. Okay, I just went back and re-watched your other videos and read your other blogs on dental health.

          I am still not understanding oatmeal.

          1. Deb

            I wouldn’t obsess about oatmeal. The only ones who make the claim that oatmeal causes dental caries are cranks with websites, low carbers, Weston Price types and the like. It is based on some old experiments from the UK done long before World War 2. They basically involved kids being fed three fairly bad diets and counting the resulting caries. The oatmeal supplemented group did worst apparently. However, porridge (oatmeal) in the UK is basically eaten with a large toppping of sugar (although in parts of Scotland, oats were traditionally eaten with a topping of salt). The possibility that sugar, now known to be a major risk for dental caries, confounded those results is obvious,.

            What does modern science tell us about this? This review from 18 years ago commented:

            “Studies of caries in animals, human plaque pH response, and enamel/dentin demineralization leave no doubt that processed food starches in modern human diets possess a significant cariogenic potential. However, the available studies with humans do not provide unequivocal data on their actual cariogenicity. In this regard, we found it helpful to distinguish between two types of situations. The first, exemplified by our forebears, people in developing countries, and special subject groups in more modern countries, is characterized by starch consumption in combination with a low sugar intake, an eating frequency which is essentially limited to two or three meals per day, and a low-to-negligible caries activity. The second, exemplified by people in the more modern societies, e.g., urban populations, is characterized by starch consumption in combination with significantly increased sugar consumption, an eating frequency of three or more times per day, and a significantly elevated caries activity. It is in the first situation that food starches do not appear to be particularly caries-inducive. However, their contribution to caries development in the second situation is uncertain and requires further clarification.”
            https://www.ncbi.nlm.nih.gov/pubmed/11021636

            and

            “A cariogenic diet is characterized by a high content of quickly fermentable carbohydrates (e.g. fructose, glucose, sucrose, or cooked starch) and the easy adherence on tooth surfaces. The frequent consumption of such substances lowers the pH of the saliva and thereby, favors the multiplication of cariogenic oral bacteria at the expense of beneficial strains [50].

            A key cause of today’s caries lesions in humans is our diet that is rich in free sugars. Beside these refined sugars, the naturally present sugars (e.g. in fruits or honey) and starch-containing foods are supposed to be cariogenic. However, the role of starch as a cariogenic or co-cariogenic substance is complex. The starch granules first need a mechanical and heat treatment to become effectively cariogenic [50, 55]. This process of gelatinization releases the glucose polymers amylose and amylopectin, which makes them susceptible to the enzymatic breakdown [55]. As an elaborated food preparation is required for this, starch can largely be ignored as a major source of caries in wild animals.”
            https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6117023/

            In, other words,avoid highly processed foods. Traditionl oats (oat groats, steel cut and even rolled oats) are less likely to cause cries than instant or quick cooking oats – and don’t eat them with sugar. I don’t think that traditional grain eating cultures (eg rice in Colin Campbell’s China Study, wheat/oats/millet in Europe/Middle East, maize in the Americas) have been noted for high rates of dental caries.

            That said, I don’t eat my oats with dried fruit like raisins any more. Dried fruits are very high in natural sugars. I use grapes – same thing but, pound for pound, the sugars are much less concentrated. That said, high fruit diets may well faciltate dental caries – this apparently even occurred in our remote ancestors – because of the sugar content.
            https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6117023/

            1. Tom,

              That was exceedingly helpful!

              I do eat steel cut oats.

              Unfortunately maple brown sugar is the flavor I really like. I tend to mix plain steel cuts with maple steel cuts with flaxseeds and a handful of walnuts.

              The flavoring is what I have to ponder.

              I also have to go back on Flouride and try the green tea.

              Thank you so much! Your sentences make sense!

            2. Mr. Fumbles said, “I wouldn’t obsess about oatmeal.”
              — – – – – –

              It’s my lowly opinion that some people obsess about food waaaay too much. Good lord, they anguish over every little thing!

              Our thoughts and attitude about what we eat have a lot to do with whether they’ll be (perceived as) healthy for us or not. According to Abraham-Hicks, if we’re not “in the vortex” even the best of foods could cause trouble.

      1. Thanks Hal!

        I have never had teeth problems before, but just got one spot, which suddenly looks like the enamel is wearing.

        So strange that I didn’t get that the years I drank soda and ate sugar all day long.

        It has caused me to look at everything and I think it might be since I switched from a fluoride toothpaste. I have been doing Tom’s. It has caused me to stop in my tracks because I don’t want to make it worse.

  7. Again, nitrates in food are a contributing factor AGAINST caries via the destruction of cariogenic bacteria and the creation of alkaline substances during that destruction. Just another reason to eat high nitrate food!

  8. My teeth are sensitive for the first time today.

    Trying to figure out what changed.

    Toothpaste did change.

    I might be missing some nutrition.

    I am not taking a D vitamin this year.

  9. So, you are saying that after eating raisins, their cavity counts dropped, we must increase our raisin intake then to have a beautiful smile without dental issues and cavities.

    1. No. I think that it is just pointing out that old beliefs about raisin consumption causing cavities appear to have no factual foundation.

      1. Dr. G. sums up his article by saying, “So, while raisins traditionally have been thought to promote tooth decay, current research suggests that raisins may not contribute to cavities after all—or at least not any more than other foods.”
        – – – – –

        As I don’t like overly sweet foods in my diet (raisins being way up thar’ on the list), I’m not about to get all happy with this current research. Gaggingly sweet is gaggingly sweet, says I.

        https://eatouteatwell.com/how-many-teaspoons-of-sugar-are-in-raisins/

        I’m probably one of the few who could stand more salt/sodium in my diet, so I’d much rather hear good things about salty foods — that they actually help us in some way. Never happen, of course.

  10. Please ofrgive me for raisin’ an off-topic subject (but I couldn’t resist the pun).

    However, those of us who will never see 21 again may appreciate kn/owing about these studies below, which I recently came across on ScienceDaily. In essence, they suggest that regular exercise may be protective against dementia and cognitive decline generally.

    “A study by a Massachusetts General Hospital (MGH) research team finds that neurogenesis -inducing the production of new neurons — in the brain structure in which memories are encoded can improve cognitive function in a mouse model of Alzheimer’s disease. Their investigation shows that those beneficial effects on cognition can be blocked by the hostile inflammatory environment present in the brain of patients with Alzheimer’s disease and that physical exercise can “clean up” the environment, allowing new nerve cells to survive and thrive and improving cognition in the Alzheimer’s mice.”
    https://www.sciencedaily.com/releases/2018/09/180906141623.htm

    There is some evidence that beneficial effects from exercise also occur in humans eg
    “For example, this study showed that exercise at an average age of 73 was associated with lower PWV five years later. So, if elderly patients get flagged with a high PWV reading or marker of subclinical brain damage, they may still have the chance to stave off dementia.

    “What’s exciting to think about is that the strong association of arterial stiffness to dementia in old age suggests that even at age 70 or 80, we might still be able to delay or prevent the onset of dementia,” Mackey said.”
    https://www.sciencedaily.com/releases/2018/10/181016132021.htm

    “The authors say their results, “show a significant relationship between physical activity, cognition, functional status and Alzheimer’s disease pathology even in individuals with genetically-driven ADAD. … The officially recommended physical activity duration of 150 minutes per week was associated with significantly better cognition and less Alzheimer’s disease pathology in ADAD. From a public health perspective, this amount of physical activity was achieved by 70% of all ADAD individuals participating at the DIAN study. Therefore, a physically active lifestyle is achievable and may play an important role in delaying the development and progression of ADAD.”

    “The results of this study are encouraging, and not only for individuals with rare genetically-caused Alzheimer’s disease,” said Maria C. Carrillo, Ph.D., Chief Science Officer for the Alzheimer’s Association. “If further research confirms this relationship between physical activity and later onset of dementia symptoms in ADAD, then we need to expand the scope of this work to see if it also is true in the millions of people with more common, late onset Alzheimer’s.”
    https://www.sciencedaily.com/releases/2018/09/180925075121.htm

    Getting back more on topic though, regarding dental health::

    “The presence of gum disease at baseline was associated with a six-fold increase in the rate of cognitive decline in participants over the six-month follow-up period of the study. Periodontitis at baseline was also associated with a relative increase in the pro-inflammatory state over the six-month follow-up period. The authors conclude that gum disease is associated with an increase in cognitive decline in Alzheimer’s Disease, possibly via mechanisms linked to the body’s inflammatory response.”
    https://www.sciencedaily.com/releases/2016/03/160310141330.htm

    1. Great links, Tom!

      Interesting about the neurogenesis being blocked by inflammation and that exercise can clean things up.

      Encouraging.

      I heart brain plasticity.

      ofrgive sounds like it would be the way someone who struggles with forgiveness might say it – with their fingers crossed behind their backs. (If you understand that cultural reference.)

      1. I watched Mississipi Burning tonight.

        I feel sick to my stomach about history.

        Human beings can seemingly justify every kind of cruelty when they have power and feel superior.

        It is still so hard to watch.

        1. Oops, see I missed a “p”

          How could I misspell?

          M-i-S-S i-S-S i-P-P i

          That one was drilled into us as kids by how fun it is to spell.

          1. Tom,

            Your fumbled forgive was good timing. While I was watching Mississippi Burning, I started thinking about how hard it would have been to forgive if I was a black person in the Sixties. I am a Christian and have forgiven people who abused me but the way people were being tortured back then was so egregious that I genuinely admire people who lived through that and forgave.

            I ended up looking up a link to Herman’s House – the Black Panther who was accused of a murder he said he didn’t commit and spent 40 years in a parking-space-sized-cell in solitary confinement: https://www.youtube.com/watch?v=_WAZjz38SBg

            Twenty-three hours a day he was in a space where he could only walk 4 steps forward and 4 steps back. The thing is, his personality was so sweet for someone locked up like that. I think I would have lost my mind and that is the wrong answer for a Christian.

            Black men and Native Americans and Foster kids and people from poverty are being held like that. I never knew they abused solitary confinement like that.

            Anyway it is so far off topic and just reflects that I am feeling a little down tonight and ended up eating Biscuits – American meaning of the word. I haven’t had them in years but Tom’s use of the word for cookie seemed to coincide with me seeing some while I was shopping and that coincided with me feeling down. It is getting colder and I don’t have a good feeling about my dog.

            He is still alive and still begging for food, but he is so finicky now that I feel like he is having stomach problems. I am not even going to tell you what he ended up eating today. Oh, he got enough calories for 2 days, but he only wants the human not good for him food, which my relatives used to give him under the table. He genuinely rejected so many foods today that I know that the end is near. But he ate so much food once I figured out which food he was begging for that I don’t know if it will be this week or next week. I just am sad.

            1. Today, I felt like he would be quoting “Green Eggs and Ham” with everything I offered, but he still kept circling his bowl and coming to the table.

            2. ‘Twenty-three hours a day he was in a space where he could only walk 4 steps forward and 4 steps back.’

              Yes, appalling. Yet we still do worse to billions of our fellow living creatures – chickens, catte, oigs, sheep and the like – for all or large parts of their lives. Often zoo animals also suffer this fate – although in many modern Western countries now, there is a movement to provide more space and a more natural environment than a concrete-floored cage.

  11. The dogs on the Turkey Tail Mushrooms lived 149 days (not sure whether that was median or average.

    it looks like he will have lived just about 5 months.

    He is still alive but I don’t see that he is getting cured and now he isn’t on a diet which would cure him.

  12. The experimental cereal with natural raisins and bran, it’s a real thing here in Denmark. I have never heard of sugar coated raisins before that is crazy

  13. Interesting that studies were done on rats with raisins since raisins are TOXIC for mice and rats and most other rodents. Look it up. In fact I unknowingly did my own study when I trapped some house mice to be released out doors when a storm was over, and kept them in a glass tank with screen top and exercise wheels and food and water. They were doing fine until I put in some raisins I had. After eating that they all died. So how does this study work??

  14. There is no high quality evidence (peer reviewed published studies) demonstrating that raisins are toxic to rats/mice. If you’re aware of one, feel free to post it here and we can evaluate it and then possibly answer your question. Please keep in mind that testimonials, blog posts and feeding raisins to some trapped animals are not considered evidence.

    Dr. Ben

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