We’ve had numerous requests for a post on the idea that dental cavities can be cured through diet. It’s a popular theme at Natural News, and Wellness Mama, along with many other websites offering “wake-up calls” and extolling the virtues of living “naturally”. From what I can gather, the enthusiasm with which the notion of “healing” cavities at home is currently being promulgated seems to be owed in large part to a book with the amusingly imperative title, Cure Tooth Decay, published in 2010 by Ramiel Nagel. It is loosely based on the work of Weston A. Price (on whom more later). All of the holistically-flavoured articles I’ve come to read on this subject mention Price, and most of them also draw from studies conducted by dentists Edward and May Mellanby. IFHP has received two or three messages from readers directing us to Natural News’ take on the subject (repeated verbatim at many other online locations). The sources it cites are: itself (twice), Wellness Mama and the Weston A. Price Foundation. Incidentally, regarding ‘wellness’, John E. Dodes, D.D.S., a dentist and outspoken critic of ‘holistic dentistry’, has noted that this is “something for which quacks can get paid when there is nothing wrong with the patient.” This note deals mostly with the claims made by NN, but also touches on some of those found elsewhere, on websites of the same bent.
So, first things first: I am not a dentist. While I have done everything I can to make this as accurate and comprehensive as possible within a reasonable amount of time, I would like to make it very clear from the outset that suggestions for improvement, particularly by dentists, are very much welcomed. First, here’s a brief word on the theory of tooth decay accepted by mainstream dentistry.
Tooth enamel is a dense tissue made mostly of hydroxyapatite, a molecule comprising calcium, phosphorus, carbon, hydrogen and oxygen. Being a-cellular, it is in fact a dead tissue, as is dentin – found directly beneath the enamel – which is also a-cellular.Enamel is is 96% minerals. (Dentin is 70%.) In the mouth, enamel is subject to constant cycles of softening and hardening. After eating foods containing fermentable carbohydrates such as sucrose, glucose and fructose, residues left in the mouth are broken down by oral bacteria, which produce lactic acid as a waste product. This local reduction in pH increases the solubility of hydroxyapatite, which begins to dissolve, in a process calleddemineralisation. However, once the sugar has gone and the pH has risen again, mineral ions suspended in the saliva are reuptaken by the tooth enamel. This part of the cycle is called remineralisation. Nowadays, the remineralisation process is enhanced by water fluoridation. Here is a useful article discussing fluoride’s multifaceted role in remineralisation: http://www.accessscience.com/studycenter.aspx?main=13&questionID=4858
The more frequently teeth are exposed to fermentable carbohydrates (particularly sucrose, see later) and acidic food, the less time the teeth have for remineralisation before they are subjected to the next round of demineralisation. As such, tooth decay (also known as ‘dental caries’) occurs when the rate of the latter exceeds that of the former, and lesions of softened, pitted enamel start to form. These weak areas represent the first stages of decay, and are sometimes known as ‘microcavities’. The good news (and herein lies our kernal of truth) is that, if treated properly with remineralising pastes, the development of these lesions can be reversed. However, once tooth decay has penetrated all the way through the enamel, forming a ‘true cavity’, this is irreversible. Why? because since enamel is a-cellular, it cannot grow. It is formed early in development by the ‘enamel organ’, which recedes by the time teeth erupt. Filling a true cavity is particularly urgent because, since the dentin is less mineralised (and therefore less resistant to the acid produced by oral bacteria), the decay process typically mushrooms out rapidly once it reaches the dentin, in a way that is sometimes described by dentists as a “cavity bomb going off inside the tooth”.
It should be borne in mind, then, that there is an important, qualitative difference between microcavities and the kind of cavities shown in this very popular picture (http://www.healthy-holistic-living.com/images/healcavities.gif), which accompanies many of the online articles in question. Later in this note, we’ll investigate the (misrepresented) source that has been exploited to gloss over this difference and promote the slap-dash notion that “cavities” can be “healed” at home.
Now for some direct quotations from Natural News:
The world is slowly waking up to the fact that, when you give the body what it needs, it can heal things we previously thought were impossible. A fine example of what is often deemed as an incurable health problem is dental cavities, but extensive research is now becoming more public about the true nature of tooth decay and the fact that there are proven remedies that can remedy it.
Starting with a sweeping statement that implies all illnesses result from not giving the body “what it needs”, is an obvious red flag. Even if it were theoretically true that all disease could be prevented by feeding the body in such a way as to match supply perfectly with demand, with the ingestion of nutrients in exactly the right measurements, at exactly the right times, not enough is known about minute-to-minute body chemistry to put such a regime into action. And that’s before considering that every human body is different. This attitude, moreover, is implicitly dismissive of congenital diseases such as cystic fibrosis, a very serious condition caused by the unlucky pairing of two dodgy mutations from mother and father, and which requires an arduous daily schedule of treatment with drugs and mechanical intervention to prevent childhood death. This opening statement is redolent of willful ignorance and unconditional distrust in medicine, and we should probably expect what follows it to be flavoured with an antiscience bias, even if it originated somewhere other than Natural News.
The lies perpetrated about tooth decay:
According to the American Dental Association, the reason we have tooth decay is as follows:
“[Tooth decay] occurs when foods containing carbohydrates (sugars and starches) such as milk, pop, raisins, cakes or candy are frequently left on the teeth. Bacteria that live in the mouth thrive on these foods, producing acids as a result. Over a period of time, these acids destroy tooth enamel, resulting in tooth decay.”
There are a few problems with this theory, including:
- Groups of indigenous people who had fermentable carbohydrates stuck on their teeth all the timethat did not brush or floss were mostly or completely free of tooth decay.
This is a reference to the work of Weston A. Price, a dentist who has inspired a lot of praise, particularly in ‘holistic’ circles (see http://www.westonaprice.org/) and a fair bit of criticism, too. See, for example:
The Quackwatch article is arguably a little harsh, and it is important to note that Price’s work has often been pilfered and warped by others to promote dodgy theories that actually bear little resemblance to his own research. The Wiki articles on him (and the dubious foundation inaugurated in his name) are worth a read.
In Nutrition and Physical Degeneration (1939), Price gives an account of his observations of “primitive” peoples from various indigenous populations around the world, reporting that they were remarkably free of diseases afflicting Westerners, including dental caries. One of his conclusions was that Western food preparation methods were stripping away nutrients, resulting in deficiencies which, he proposed, explained tooth decay (and other diseases). During his research, Price observed that these indigenous groups, when they moved towards more Western diets, began to develop dental caries, interpreting this as support for his theory.
Price did in fact believe that sugar was a significant cause of dental caries, but hypothesised (incorrectly) that its cariogenic (tooth decay-inducing) action was to reduce the amount of minerals absorbed by the body. It wasn’t until the 1940s and 50s that the actual role of sugar in tooth decay was discovered, so this was a valid hypothesis at the time. Full appraisal of Price’s work is far beyond the remit of this note but, in short, it seems he did some interesting research which perhaps fell short on scientific and quantitative rigour. Some quick points:
- Malnourished people, overrepresented in Price’s subjects, get fewer dental cavities, as they experience longer periods of time without dental exposure to food.
- The serious increases in tooth decay experienced by indigenous people who then gained access to Western foods could be explained by overindulgence, by virtue of sugary foods being a novelty to them.
- Archaeological evidence tells us that tooth decay is not exclusive to Westernised society. For example, here is recent study finding caries in humans from more than 13,700 years ago. http://www.bbc.co.uk/news/science-environment-24332237
- Price’s research was conducted before the time of vitamin-fortification of Western processed carbohydrates, before the time of water fluoridation, and during a time when tooth decay in the Western world was almost at its highest in history (it reached a peak during the 50s and 60s). For a full-text review of the history of dental caries, published by Nature,see http://www.nature.com/bdj/journal/v191/n9/full/4801214a.html
- Despite the controversy surrounding Price’s work, it is actually compatible with a sugar-centric theory of tooth decay.
- I have not been able to give the time it would take to read Price’s entire book, but after the research I’ve done around this subject, it seems unlikely that he claimed his subjects “had fermentable carbohydrates stuck to their teeth all the time”, as reported by Natural News.
Here is a link to an e-version of Price’s book, which is now in the public domain: http://gutenberg.net.au/ebooks02/0200251h.html#ch1
- Bacteria do not consume processed sugar or flour because of the lack of nutrients in them
This is a bizarre statement, made, Naturally, without any supporting reference. There is ample evidence that sucrose, the molecule constituting refined sugar, is eaten by bacteria in the mouth. De-germed (processed) flour contains less (though not nothing) in the way of vitamins, minerals and protein, but is full of polysaccarides, which can be digested by oral bacteria. In any case, the mouth contains a multitude of essential nutrients with which bacteria can supplement their diets. Here are a few references to support the role played by sucrose in caries-formation:
Krasse B, Edwardsson S, Svensson I, Trell L. Implantation of caries-inducing streptococci in the human oral cavity. Arch Oral Biol 1967;12:231–6
Minah GE, Lovekin GB, Finney JP. Sucrose-induced ecological response of experimental dental plaques from caries-free and caries-susceptible human volunteers. Infect Immun 1981;34:662–75.
Sheiham A. Sucrose and dental caries. Nutrition Health 1987; 5: 25–29.
Van Houte J, Upeslacis VN, Jordan HV, Skobe Z, Green DB. Role of sucrose in colonization of Streptococcus mutans in conventional Sprague-Dawley rats.J Dent Res 1976;55:202–15.
Another, related angle of attack (not included in the NN article) comes from Cure Tooth Decay by Ramiel Nagen. It is repeated in various online articles similar to the one from Natural News. It goes like this:
[Mainstream theory of tooth decay] further dissolves because white sugar actually has the ability to incapacitate microorganisms since it attracts water. In a 20% sugar solution, bacteria will perish. Yes, bacteria are present as a result of the process of tooth decay, but a lot of sugar at once will destroy them. If dentistry is correct about bacteria, then a high sugar diet should eliminate them.
Nagen clearly reckons he’s delivered a real blow with this one. To somebody who has never studied biology, perhaps it sounds like the kind of simple, razor-sharp idea that seems so obvious when voiced that everyone says, “why didn’t I think of that?” Only, this idea is toosimple. It’s one thing to plonk a blob of bacterial cells into a beaker of sugar solution and leave them there, out on a limb, floating around in an abyss with nowhere to hide. As long as the percentage of solutes in the liquid contained inside the cells is lower than the percentage of solutes contained outside them in the external solution, osmosis will ensure that the cells’ watery insides are sucked out, desiccating the little blighters as molecules strive towards equilibrium from both sides of their outer membranes. (http://en.wikipedia.org/wiki/Osmosis) But this lab situation is completely different from the one going on in the human mouth, which doesn’t have smooth glassy surfaces, for one thing. The bacteria in the mouth are established residents. They’ve worked their way into all the nookiest nooks and the cranniest crannies, living in gooey bundles, all huddled up together, nice and cosy. They nuzzle between teeth and ensconce themselves under the harbourage of the gum-line. They squelch around in a caggy spread on the rough, grainy surface of the back of the tongue. Most importantly of all, to help them nuzzle and congregate thus, oral bacteria manufacture an extrapolysaccharide (EPS) slime, also known as a biofilm, using broken-down sugar. This EPS acts as a protective sheath against dessication, holds them together, and keeps them glued to their terrain. Biofilms are why dentists stress the importance of mechanical cleaning with brushes and floss – your antibacterial mouthwash might have “kills 99% of oral bacteria” printed on it, but this kill-rate is likely based on tests with bacteria unprotected by biofilms. When a host human chomps up a cake, the sugary, masticated stodge might feasibly break through some patches of bacterial biofilm, in a similar way to a toothbrush, displacing some of the unlucky bacteria on the outskirts of the huddles, and dragging them, stomach-wards, down the oesophagus. But once the cake-eating eating has stopped, the plentiful remaining bacteria will of course begin spreading over the fermentable residue, digesting it and multiplying afresh.
- Foods that bacteria like to eat, such as milk, vegetables, meat, fish and fruit, are not commonly implicated in causes of tooth decay.
Lactose does not appear to be as cariogenic (decay-inducing) as other mono- and di-saccarides. It also tends to be consumed in the presence of other food components such as proteins, fats, and minerals from milk and other dairy products, which act as a buffer, minimising its carious impact. Milk and other dairy products also contains calcium phosphate and casein, both of which aid in the remineralisation process. Fruit, which contains fructose, glucose and some sucrose, doesn’t seem to be a major player in tooth decay, though its acid content can be a cause of tooth erosion, particularly in juice-form, which can increase susceptibility. Something not acknowledged in the NN statement above is that people who eat lots of fruit also probably tend to eat fewer doughuts, meaning that their overall sucrose-intake may be lower. It’s worth pointing out, also, that there is a staggering diversity of bacterial species, some of which have even evolved to digest radioactive material. The phrase “bacteria like to eat” fails to acknowledge the fact that different species of bacteria have different tastes. A class of bacteria called the mutans streptococci represent the main culprits in tooth decay. Of these species, S. sobrinus and S. mutans are the most highly associated with carious lesions on the teeth. The reason sucrose (not found in high concentrations in milk, vegetables, meat, fish, or even fruit) is the biggest dietary factor in tooth decay is because these bacteria specifically rely on it to manufacture sticky, long-chain molecules called glucans, the main ingredient of EPS, discussed above. Thus, the idea that some “foods that bacteria like to eat” are not implicated in tooth decay is not at odds with the modern theory of tooth decay – none of the foods listed in this bacterial tasting menu, à la Natural News, are particularly high in sucrose. See the following papers for further reading on the cariogenicity of lactose and fruit.
http://www.nature.com/bdj/journal/v193/n10/full/4801628a.html#B18 (free full-text article)
So if the modern explanation of tooth decay is not accurate, what is actually the cause of tooth decay?
What actually causes tooth decay
Tooth decay, as researched by Dr. Weston Price and other dental pioneers, boiled down to three factors:
- Not enough minerals in the diet.
- Not enough fat-soluble vitamins (A, D, E, and K) in the diet.
- Nutrients not being readily bioavailable, and your intestinal system not properly absorbing them.The presence of phytic acid largely influences this factor.
Over a period of time, if your diet lacks vitamins and minerals from a poor diet and/or contains high levels of phytates (from grains, seeds, nuts, and legumes), the blood chemistry and the ratio of calcium and phosphorous become out of balance, which results in minerals being pulled from bones, causing tooth and bone loss.
So, the long-standing belief that sugar causes tooth decay is true, but as a result of it depleting nutrients from the body, not because bacteria eat it and produce acid that ruins your teeth.
“Other dental pioneers” appears to be a reference to Dr. May Mellanby and Dr. Edward Mellanby (who discovered vitamin D). These two doctors did a lot of work on the effect of vitamins on tooth structure and decay. The graph, which comes from (http://wholehealthsource.blogspot.co.uk/2009/03/reversing-tooth-decay.html) has been reproduced in a large number of other online articles making claims similar to those made by Natural News. I must have seen it in at least six or seven articles. It is based on the summary of Dr. May Mellanby et al’s series of experiments done on children in hospitals, and, as far as I can tell, seems to be an accurate representation. Except for one crucial ambiguity. The graph uses the word “healing” (unqualified), in the context of “cavities”, neglecting to mention the difference between microcavities (lesions of softened, demineralised enamel) and true cavities – actual holes in the enamel. While softened and weak enamel can remineralise, it cannot grow back, as explained earlier in this note. I will say it again: this crucial difference between the early and late stages of tooth decay is something that is systematically ignored by all the web pages advising readers to ditch the dentist in favour of “natural” cures for “cavities”, a term which they fail to qualify. Some points on the Mellanby studies:
- Supplementation of vitamin D (which is needed for absorption of calcium, a major component of teeth, as discussed above) was indeed found to have an ameliorative effect on dental caries, and the recommendation is made, in the concluding summary, that sufficient vitamin D and calcium should be consumed by mothers during pregnancy and by offpring from birth.
- But the amelioration should not be, and was not, described by Mellanby simply as the “healing” of cavities, as it is in all these over-zelous articles. The improvements seen in Mellanby’s experiments were:
- hardening of carious lesions on the enamel (ie. remineralisation of microcavities, something accounted for uncontroversially within mainstream dentistry) – the word “healing”, out of context, is misleading, especially when the picture presented at the top of the NN the article (and others) is one of multiple, plainly visible, gaping holes in the enamel surfaces of a set of teeth.
- The laying down of tertiary protective dentin (dentin being the calcified tissue just below the enamel) in cavities that had already penetrated the enamel. Again, the observation that this response can occur in teeth, arresting the development of caries, is encompassed by modern dental theory. However, there is still debate surrounding how commonly and under what circumstances this occurs. This ‘laying down’ of new dentin, when it occurs, is achieved by the living pulp (remember, dentin is dead tissue). However, this new dentin does not extend very far, and is irregular in structure and far less dense than primary or secondary dentin*, so extremely vulnerable to further decay.
- Whereas, across all the other diets studied experimentally by Mellanby, carbohydrate content was kept constant, carbohydrate content was considerably lowered in the cereal-free (low phytic acid) diet. Now that we know about the role of fermentable carbohydrates in tooth decay, this should be flagged up as confounding factor in the experiment’s results and the author’s conclusion regarding the detrimental effect of phytic acid on teeth, an idea which is so popular in current-day articles on natural “healing” of tooth cavities, as well as in “paleo” circles. Phyates are now not considered to have a detrimental effect on teeth. (In fact, when isolated from foods, they have even been found to have an anti-caries effect, though this doesn’t carry through to when they are eaten as an intrinsic component of food.)
- Mellanby herself was clear in pointing out that, even on a high-vitamin D diet, “caries is not arrested in all children”, saying that it “appeared that there might well be dietic factors apart from vitamin D influencing the carious process”, and recognising “that some local chemico-parasitic condition in the mouth might explain the continued activity of caries at some points”. She was right, of course – “chemico-parasitic” being a rather apt way to describe the condition imposed by the presence of lactic acid-producing bacteria.
- Again, this work was done during a time before vitamin-fortification of cereals and processed carbohydrates, before sugar was identified as the main causal factor in tooth decay, before water fluoridation, and during a time when, accordingly, tooth decay was rife.
The full text version of the report on all four experiments conducted by Mellanby et al. on tooth decay progression in children, from which the graph is taken, can be found here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2520490/?page=3. In fact, all of the Mellanby articles are available online in full.
The food remedies that can heal cavities and tooth decay
In order to restore the ratio of calcium and phosphorus in our blood, and to enable minerals to bond to our teeth, it is not enough to just avoid eating too many sweet or processed foods. We must also eat health-building foods, containing copious amounts of minerals and vitamins that will build a glassy hard tooth structure.
Foods to focus on are:
- Coconut oil, grass-fed organic dairy (especially butter), grass-fed meats, seafood and bone broths.
- Organic cooked vegetables (soups with bone broth are ideal).
- Organ and gland meats, like liver.
Limit foods that are high in phytic acid, like grains, beans, nuts and seeds, as well as limiting processed food intake full of processed flours and sugars that upset blood sugar balance.
Supplements to consider are:
- Fermented cod liver oil – very high in fat soluble vitamins A, D and K.
- Magnesium – required to use calcium and phosphorous effectively.
- Gelatin – if you don’t have time to make bone broth, this is a good alternative and is great for gums and digestion.
Now go get your pearly white smile back.
The idea that every one of us needs to be working to “restore” the ratio of calcium and phosphorus in our blood has no basis. Aside from being the conclusion of an article deliberately based on anachronistic theory from the 1920s and 30s (and loosely, at that), in general, people who eat reasonable diets based on standard dietary recommendations have no reason to believe that they are suffering from nutritional deficiencies or inbalances. Claims that modern dentistry dismisses the importance of nutrition for healthy teeth are false. Evidence points to the importance of nutrition in the pre-eruptive stage, when teeth are forming, and deficiencies in (for example) vitamin D and A, as well as protein energy malnutrition, have all been linked with poor enamel composition (enamel hypoplasia), which increases susceptibility to tooth decay (see following reference). Furthermore, other nutrient deficiencies are recognised to interfere with saliva composition and quantity (http://ajcn.nutrition.org/content/78/4/881S.full), minimising its protective effect. But in healthy people who eat a normal, balanced diet, in the post-eruptive stage, by far the most important cause of tooth decay is sugar consumption. The authors of the articles addressed in this note offer dental advice but, in so doing, clearly demonstrate that they are neither qualified nor equipped to do so. When seeking out advice on how to maximise the health of your teeth, be sure to check for accreditation by dentists. If you think you’re at risk of being subjected to unnecessary drilling and filling, ask your dentist whether remineralisation with fluoride therapy is a possible alternative. If you still suspect him/her of ‘over-enthusiasm’, go and get a second opinion. But don’t abandon dental appointments in favour of diet regimes invented in the 1930s, before the era of food fortification, water fluoridation, or an understanding of sugar’s role in tooth decay.
For a full-text read on teeth and nutrition: http://www.nature.com/bdj/journal/v193/n10/full/4801628a.html#B18
*These experiments were conducted in the 20s and 30s. At that time, what is now called tertiary dentin was then known as secondary dentin. The new category reflects the greater understanding dentists now have of tooth structure and function. Thanks to dentist Adrian Stewart, who provided the following explanation in a comment: Secondary dentin is laid down on the inner wall of the dentin throughout the life of the pulp. Dentin is tubular in structure (diameter of approx. 1 micron) with an ondontoblast (the cell that makes dentin and secondary dentin) at the interface of the pulp and he dentin tubule, with a cell process extending into the tubule. Decay entering the dentin leads to death of this ondontoblast, which is replaced by a prto-ondontoblast from pluripotent stem cells within the dental pulp. These then lay down irregular tertiary dentin, which is nowhere near as dense as primary or secondary dentin but acts as a basic defense against the decay process.