Preventing Tooth Decay

Meet Sir Edward Mellanby, the man who discovered vitamin D. Along with his wife, Dr. May Mellanby, he identified dietary factors that control the formation and repair of teeth and bones. He also identified the primary cause of rickets (vitamin D deficiency) and the effect of phytic acid on mineral absorption. Truly a great man! This research began in the 1910s and continued through the 1940s.

What he discovered about tooth and bone formation is profound, disarmingly simple, and largely forgotten. I remember going to the dentist as a child. He told me I had good teeth. I informed him that I tried to eat well and stay away from sweets. He explained to me that I had good teeth because of genetics, not my diet. I was skeptical at the time, and rightly so.

Tooth structure is primarily determined during growth. Well-formed teeth are highly resistant to decay, while poorly-formed teeth are cavity-prone. Drs. Mellanby demonstrated this by showing a strong correlation between tooth enamel defects and cavities in British children. The following graph is drawn from several studies he compiled in the book Nutrition and Disease (1934). "Hypoplastic" refers to enamel that's poorly formed on a microscopic level.
The graph is confusing, so don't worry if you're having a hard time interpreting it. If you look at the blue bar representing children with well-formed teeth, you can see that 77% of them have no cavities, and only 7.5% have severe cavities (a "3" on the X axis). Looking at the green bar, only 6% of children with the worst enamel structure are without cavities, while 74% have severe cavities. Enamel structure is VERY strongly related to cavity prevalence.

What determines enamel structure during growth? Drs. Mellanby identified three dominant factors:

1. The mineral content of the diet
2. The fat-soluble vitamin content of the diet, chiefly vitamin D
3. The availability of minerals for absorption, determined largely by the diet's phytic acid content

Teeth and bones are a mineralized protein scaffold. Vitamin D influences the quality of the protein scaffold that's laid down, and the handling of the elements that mineralize it. For the scaffold to mineralize, the diet has to contain enough minerals, primarily calcium and phosphorus. Vitamin D allows the digestive system to absorb the minerals, but it can only absorb them if they aren't bound by phytic acid. Phytic acid is an anti-nutrient found primarily in unfermented seeds such as grains. So the process depends on getting minerals (sufficient minerals in the diet and low phytic acid) and putting them in the right place (fat-soluble vitamins).

Optimal tooth and bone formation occurs only on a diet that is sufficient in minerals, fat-soluble vitamins, and low in phytic acid. Drs. Mellanby used dogs in their experiments, which it turns out are a good model for tooth formation in humans for a reason I'll explain later. From Nutrition and Disease:

Thus, if growing puppies are given a limited amount of separated [skim] milk together with cereals, lean meat, orange juice, and yeast (i.e., a diet containing sufficient energy value and also sufficient proteins, carbohydrates, vitamins B and C, and salts), defectively formed teeth will result. If some rich source of vitamin D be added, such as cod-liver oil or egg-yolk, the structure of the teeth will be greatly improved, while the addition of oils such as olive... leaves the teeth as badly formed as when the basal diet only is given... If, when the vitamin D intake is deficient, the cereal part of the diet is increased, or if wheat germ [high in phytic acid] replaces white flour, or, again, if oatmeal [high in phytic acid] is substituted for white flour, then the teeth tend to be worse in structure, but if, under these conditions, the calcium intake is increased, then calcification [the deposition of calcium in the teeth] is improved.

Other researchers initially disputed the Mellanbys' results because they weren't able to replicate the findings in rats. It turns out, rats produce the phytic acid-degrading enzyme phytase in their small intestine, so they can extract minerals from unfermented grains better than dogs. Humans also produce phytase, but at levels so low they don't significantly degrade phytic acid. The small intestine of rats has about 30 times the phytase activity of the human small intestine, again demonstrating that humans are not well adapted to eating grains. Our ability to extract minerals from seeds is comparable to that of dogs, which shows that the Mellanbys' results are more applicable to humans than those in rats.

Drs. Mellanby found that the same three factors determine bone quality in dogs as well, which I may discuss in another post.

Is there anything someone with fully formed enamel can do to prevent tooth decay? Drs. Mellanby showed (in humans this time) that not only can tooth decay be prevented by a good diet, it can be almost completely reversed even if it's already present. Dr. Weston Price used a similar method to reverse tooth decay as well. I'll discuss that in my next post.

The Benefits of Growing Algae in Your Water Filter

One of the factors that's often overlooked in our efforts to replicate the health of non-industrial cultures is water quality. Traditional cultures don't drink sterilized, chlorinated, fluoridated tap water. They drink from natural flowing streams and lakes, complete with their natural minerals, and... algae.

With every gulp, they ingest millions or even billions of tiny green organisms entirely missing from the modern water supply (1).

Fortunately, we can drink algae water too. As a matter of fact, millions of lazy people are doing it right now! All you have to do is buy a clear water filter, use it regularly and leave it in the sun. Over time, you'll develop your very own film of algae that will constantly shed into the water you drink. Here are some of the benefits of algae water:

• Adds oxygen to the water, increasing your energy on a cellular level!
• Probiotics in every cup
• Algae are full of vitamin K. Who needs spinach!
• Make your own biofuel

4 out of 5 scientists agree that a cup of algae water equals 3.7 servings of vegetables (2).

April fools!

Reversing Tooth Decay

In the last post, I discussed the research of Drs. Edward and May Mellanby on the nutritional factors affecting tooth formation. Dr. Mellanby is the man who discovered vitamin D and identified the cause of rickets. Nutrition has a profound effect on tooth structure, and well-formed teeth are inherently resistant to decay. But is there anything you can do if your teeth are already formed?

Teeth are able to heal themselves. That's one reason why traditional cultures such as the Inuit can wear their teeth down to the pulp due to chewing leather and sand-covered dried fish, yet still have an exceptionally low rate of tooth decay. It's also how the African Wakamba tribe could traditionally file their front teeth into sharp points without causing decay. Both cultures lost their resistance to tooth decay after adopting nutrient-poor Western foods such as white flour and sugar.

Teeth are made of four layers. Enamel is the hardest, most mineralized outer shell. Dentin is another protective mineralized layer that's below the enamel. Below the dentin is the pulp, which contains blood vessels and nerves. The roots are coated with cementum, another mineralized tissue.

When enamel is poorly formed and/or the diet isn't adequate, enamel demineralizes and decay sets in. Tooth decay is an opportunistic infection that takes advantage of poorly developed or maintained teeth. If the diet remains inadequate, the tooth has to be filled or removed, or the person risks more serious complications.

Fortunately, a decaying or broken tooth has the ability to heal itself if the diet is good, including by remineralizing enamel and dentin, and/or forming a limited quantity of new dentin. This new dentin is deposited by specialized cells called odontoblasts. Here's what Dr. Edward Mellanby had to say about his wife's research on the subject. This is taken from Nutrition and Disease:

Since the days of John Hunter it has been known that when the enamel and dentine are injured by attrition or caries, teeth do not remain passive but respond to the injury by producing a reaction of the odontoblasts in the dental pulp in an area generally corresponding to the damaged tissue and resulting in a laying down of what is known as secondary dentine. In 1922 M. Mellanby proceeded to investigate this phenomenon under varying nutritional conditions and found that she could control the secondary dentine laid down in the teeth of animals as a reaction to attrition both in quality and quantity, independently of the original structure of the tooth. Thus, when a diet of high calci­fying qualities, ie., one rich in vitamin D, calcium and phosphorus was given to the dogs during the period of attrition, the new secondary dentine laid down was abundant and well formed whether the original structure of the teeth was good or bad. On the other hand, a diet rich in cereals and poor in vitamin D resulted in the production of secondary dentine either small in amount or poorly calcified, and this happened even if the primary dentine was well formed.

Thus, in dogs, the factors that affect tooth healing are the same factors that affect tooth development:

1. The mineral content of the diet, particularly calcium and phosphorus
2. The fat-soluble vitamin content of the diet, chiefly vitamin D
3. The availability of minerals for absorption, determined largely by the diet's phytic acid content (prevents mineral absorption)

What about humans? Drs. Mellanby set out to see if they could use their dietary principles to cure tooth decay that was already established. They divided 62 children with cavities into three different diet groups for 6 months. Group 1 ate their normal diet plus oatmeal (rich in phytic acid). Group 2 ate their normal diet plus vitamin D. Group 3 ate a grain-free diet and took vitamin D.

In group 1, oatmeal prevented healing and encouraged new cavities, presumably due to its ability to prevent mineral absorption. In group 2, simply adding vitamin D to the diet caused most cavities to heal and fewer to form. The most striking effect was in group 3, the group eating a grain-free diet plus vitamin D, in which nearly all cavities healed and very few new cavities developed. Grains are the main source of phytic acid in the modern diet, although we can't rule out the possibility that grains were promoting tooth decay through another mechanism as well.

Dr. Mellanby was quick to point out that diet 3 contained some carbohydrate (~45% reduction) and was not low in sugar: "Although [diet 3] contained no bread, porridge or other cereals, it included a moderate amount of carbohydrates, for plenty of milk, jam, sugar, potatoes and vegetables were eaten by this group of children." This study was published in the British Medical Journal (1) and the British Dental journal. Here's Dr. Edward Mellanby again:

The hardening of carious areas that takes place in the teeth of children fed on diets of high calcifying value indicates the arrest of the active process and may result in “healing” of the infected area. As might be surmised, this phenomenon is accompanied by a laying down of a thick barrier of well-formed secondary denture... Summing up these results it will be clear that the clinical deductions made on the basis of the animal experiments have been justified, and that it is now known how to diminish the spread of caries and even to stop the active carious process in many affected teeth.

Dr. Mellanby first began publishing studies showing the reversal of cavities in humans using diet in 1924. Why has such a major medical finding, published in high-impact peer-reviewed journals, faded into obscurity?

Dr. Weston Price also had success curing tooth decay using a similar diet. He fed poor children one very nutritious meal a day and monitored their dental health. From Nutrition and Physical Degeneration (p. 290):

About four ounces of tomato juice or orange juice and a teaspoonful of a mixture of equal parts of a very high vitamin natural cod liver oil and an especially high vitamin butter was given at the beginning of the meal. They then received a bowl containing approximately a pint of a very rich vegetable and meat stew, made largely from bone marrow and fine cuts of tender meat: the meat was usually broiled separately to retain its juice and then chopped very fine and added to the bone marrow meat soup which always contained finely chopped vegetables and plenty of very yellow carrots; for the next course they had cooked fruit, with very little sweetening, and rolls made from freshly ground whole wheat, which were spread with the high-vitamin butter. The wheat for the rolls was ground fresh every day in a motor driven coffee mill. Each child was also given two glasses of fresh whole milk. The menu was varied from day to day by substituting for the meat stew, fish chowder or organs of animals.

Dr. Price provides before and after X-rays showing re-calcification of cavity-ridden teeth on this program. His intervention was not exactly the same as Drs. Mellanby, but it was similar in many ways. Both diets were high in minerals, rich in fat-soluble vitamins (including D), and low in phytic acid.

Price's diet was not grain-free, but used rolls made from freshly ground whole wheat. Freshly ground whole wheat has a high phytase (the enzyme that degrades phytic acid) activity, thus in conjunction with the long yeast rises common in Price's time, it would have broken down nearly all of its own phytic acid. This would have made it a source of minerals rather than a sink for them. He also used high-vitamin pastured butter in conjunction with cod liver oil. We now know that the vitamin K2 in pastured butter is important for bone and tooth development and maintenance. This was something that Dr. Mellanby did not understand at the time, but modern research has corroborated Price's finding that K2 is synergistic with vitamin D in promoting skeletal and dental health.

If I were to design the ultimate dietary program to heal cavities that incorporates the successes of both doctors, it would look something like this:

• Rich in animal foods, particularly full-fat pastured dairy products (if tolerated) and bone broths. Also meat, organs, fish, and eggs.
• Fermented grains only; no unfermented grains such as oatmeal, breakfast cereal, crackers, etc. No breads except true sourdough (ingredients should not list lactic acid). Or even better, no grains at all.
• Limited nuts; beans in moderation, only if they're soaked overnight or longer prior to cooking (due to the phytic acid).
• Starchy vegetables such as potatoes and sweet potatoes.
• A limited quantity of fruit (one piece per day or less), but no refined sweets.
• Cooked and raw vegetables.
• Sunlight, high-vitamin cod liver oil, or vitamin D3 supplements.
• Pastured butter.
• No industrially processed food.

This diet would maximize mineral absorption while providing abundant fat-soluble vitamins. It probably isn't necessary to follow it strictly. For example, if you eat more mineral-rich foods such as dairy and bone broths, you can probably get away with more phytic acid. Or you might be able to heal cavities eating like this for only one or two meals a day, as Dr. Price demonstrated. 

This post is focused on diet, but obviously oral hygiene also matters.  Brushing your teeth, flossing, and rinsing your mouth out after meals will also reduce dental risks.  

The technique described above is applicable to early-stage, small cavities, not necessarily to advanced decay.  If you try to heal your own cavities using diet, please do it under the supervision of a dentist.  

A New Way to Soak Brown Rice

I've been looking for a way to prepare whole brown rice that increases its mineral availability without changing its texture. I've been re-reading some of the papers I've accumulated on grain processing and mineral availability, and I've found a simple way to do it.

In the 2008 paper "Effects of soaking, germination and fermentation on phytic acid, total and in vitro soluble zinc in brown rice", Dr. Robert J. Hamer's group found that soaking alone didn't have much of an effect on phytic acid in brown rice. However, fermentation was highly effective at degrading it. What I didn't realize the first time I read the paper is that they fermented intact brown rice rather than grinding it. This wasn't clear from the description in the methods section but I confirmed it by e-mail with the lead author Dr. Jianfen Liang. He added that the procedure comes from a traditional Chinese recipe for rice noodles. The method they used is very simple:

1. Soak brown rice in dechlorinated water for 24 hours at room temperature without changing the water. Reserve 10% of the soaking liquid (should keep for a long time in the fridge). Discard the rest of the soaking liquid; cook the rice in fresh water.
2. The next time you make brown rice, use the same procedure as above, but add the soaking liquid you reserved from the last batch to the rest of the soaking water.
3. Repeat the cycle. The process will gradually improve until 96% or more of the phytic acid is degraded at 24 hours.

This process probably depends on two factors: fermentation acidifies the soaking medium, which activates the phytase (phytic acid-degrading enzyme) already present in the rice; and it also cultivates microorganisms that produce their own phytase. I would guess the latter factor is the more important one, because brown rice doesn't contain much phytase.

You can probably use the same liquid to soak other grains.

Wow

Last Thursday, the post "Reversing Tooth Decay" made it to the front page of Reddit, a news aggregator site. I ended up getting 46,429 hits that day, and another 8,646 the next day. I normally hover between 1,500 and 3,000.

It was a wild ride. I'd like to send out a big thanks to whoever posted the article to Reddit, and everyone who voted for it. I appreciate you helping to spread the message.

Dental Anecdotes

Here are a few anecdotes gleaned from past comments that describe improvements in oral health due to a change in diet. Please feel free to add your own (positive or negative) experience to the comments. I may add it to the post.

Stan: My teeth stopped decaying and some breakage (broken tooth due to mechanical damage, 5 years ago) begun sealing itself with new enamel on my high animal fat, low carb diet of the last 10 years. I still have all my teeth including wisdom teeth. My teeth no longer develop plaque/scale and thus no need to descale, and I no longer develop cold sores on my gums. I haven't been to a dentist since 1999 (I am 53). [From another comment] I can fully confirm the astounding effect of a diet very high in animal produce and low in plants, on my teeth. My tooth decay has totally stopped! I wrote about that before but it is worth repeating: - my teeth would not decay even if mechanically damaged, broken in half etc. The broken exposed parts of a tooth, even if the core is open, just seals itself over time.

Dave: Our family has had similar experiences. In particular, my daughter had a poorly formed molar (she was a spring baby, before we started Vitamin D, hmmmm). The tooth had quite a large crater in it. I put her on D3 and cod liver oil/butter oil. We finally got a dentist she'd cooperate with enough for X-rays. The result was exactly as described above: a thick layer of dentin had formed. The dentist was thoroughly puzzled, which I enjoyed immensely :-)

Arnoud: For years my dentist has been insisting on more frequent and more aggressive cleaning techniques.... to no avail. Last year I started Vitamin D supplementation, and a more Paleo style of diet, and the 'chronic' inflammation of my gums resolved themselves within days, literally. My dentist claims it is a coincidence. I think not!

Martin: Once I changed my diet to one close to what is listed in this entry, and added a vitamin D3 supplement, my dental health greatly improved. No more cavities, and beyond that, no more rapid build-up of dental plaque. To prevent gum problems, I used to have to get my teeth cleaned four times a year, now, once a year is enough, and it seems to me, even that might not be necessary.

Thresshold: I am a cavity-every-six-months person, who arrested decay for 3 years by going on a Protein Power-like diet. No limit on non-starchy veggies, lots of meat-- turkey, beef --lots of nuts, olive oil, egg a day. No grains. Very little fruit, no sugar. Plenty of supplemented vitamin A and D, E, C, Bs, some dolomite.

Jeff: I just had a dentist visit, first in almost 3 years. No cavities for the first time in a while. Your advice and a Paleo diet are the reason, in my mind.

Dr. Dan: Before paleo I had bleeding gums and sore teeth. Now that I have been on it I have not had them and my flatmate just commented how white my teeth are looking.

Cheeseslave: I have also eliminated cavities since I changed the way I eat. I avoid all phytic acid (I try to only eat sprouted bread or naturally fermented sourdough) and I soak or sprout all my grains, legumes, nuts and seeds. I also take cod liver oil, and eat a nutrient-dense diet consisting of mostly meat and dairy.

Dr. B. G.: Myself, I had periodontal disease (esp immed after pregnancy and lactation -- wonder W-H-Y ??!) however at the last check up -- I have no more pockets of '5' and am released to come in only 2x annually instead of all the extra (painful) de-planing and cleanings. This was improved by: vitamin A, vitamin D 5000 IU every am, high dose fish oil, flaxseed and egg yolks and saturated fats and some K2 supplements. [From another comment] I have to admit -- my dental problems reversed prior to total Paleo eating (eg, wheat-free). On vitamin D and fish oil alone my cavities sealed. In fact I had gone back to see the DDS but he couldn't find one tiny 'sticky' spot. When he decided to fill it irregardless (and I was an idiot to not walk out b/c who knew that cavities could heal/seal...on their own??), then I had to leave him. At that point, the dental hygienist had already let me return to a 'normal' insured 2 cleanings/yr schedule, instead of the $$ 4/year (where 2 were out-of-pocket). With going 100% wheat-free, vits ADEK and adding a little (fresh highquality) flaxseed oil, my gums are super healthy and no throbbing at all for the last 9mos!

Brock: When I went to my dentist for the first time in a while last September I was told I had six cavities. My dentist told me to schedule to get them filled in, but I never did. I just had the intuitive feeling that the human body ought to be able to heal itself, and that for some reason my dentist just didn't know how. So, I started Googling. My search lead me here and to the Weston Price Foundation. I bought Dr. Price's book and changed by diet months ago. I eat mostly paleo but mainly just focus on avoiding wheat, corn, sugar and n6 fats. I supplement with Vitamins A, C, D, E and K2. Long story short, my six cavities have closed up and my teeth have noticeably improved in color and "feel". Swelling in my gums is down. I can often go for weeks now without brushing my teeth without any noticeable side effects. It's great.

Andrew S.:I had a lot of cavities growing up, and as a young adult. I started up a new company, didn't have health insurance, and didn't go to the dentist in a while -- and started eating whole, natural foods, with a bit of supplementation (mostly cod liver oil). I was surprised when I visited the dentist for the first time in years to not have any decay.

Robert Andrew Brown: I too have gone from regular cavities, indifferent gum health, sensitive teeth, and a host of dental work to prove it, to none since balancing the Omega 3s and 6s, and regular 'industrial' cod liver oil. Small carries that were sensitive and on the list for restorative work have re mineralised and skinned over but not refilled. I have only recently started seriously increasing vitamin D and reintroducing grass fed butter.

Modern Diet-Health Epidemiology: a Self-Fulfilling Prophecy? Part I

Epidemiology is the study of population statistics to learn about health. It can provide simple information such as the prevalence of hepatitis C in a particular region, or it can provide more complex information such as the association between dietary patterns and gout. It has brought us many great things, from its roots in understanding the transmission of communicable diseases, to the identification of smoking as the probable cause of lung cancer.

Observational studies are a mainstay of epidemiology. In observational studies, investigators gather data passively rather than manipulating variables. For example, if you want to know if people who wear tight shoes develop bunions, you would find a group of people who wear tight shoes and one that doesn't. You would try your best to make sure the groups are the same in every way besides shoe tightness: age, gender, weight, etc. Then you would follow them for 10 years to see how many people in each group develop bunions. You would then know whether or not wearing tight shoes is associated with bunions.

Observational data can never tell us that one thing caused another, only that the two are associated. The tight shoes may not have caused the bunions; they may simply have been associated with a third factor that was the true cause. For example, maybe people who wear tight shoes also tend to eat corn flakes, and corn flakes are the real cause of bunions. Or perhaps bunions actually cause people to wear tight shoes, rather than the reverse. Observational data can't resolve these questions definitively.

To establish causality, you have to do a controlled trial. In the case of our example, we would select 2,000 people and assign them randomly to two groups of 1,000. One group would wear tight shoes while the other would wear roomy shoes. After 10 years, we would see how many people developed bunions in each group. If the tight shoe group had more bunions, we could rightly say that tight shoes cause bunions. The reason this works is the randomization process (ideally) eliminates all differences between the groups except for the one you're trying to study. You should have the same number of corn flake eaters in each group if the randomization process worked correctly.

A less convincing but still worthwhile alternative would be to put tight and loose shoes on mice to see if they develop bunions. That's what researchers did in the case of the tobacco-lung cancer link. Controlled studies in animals reinforced the strong suggestion from epidemiological studies that smoking increases the risk of lung cancer.

Finally, another factor in determining the likelihood of associations representing causation is plausibility. In other words, can you imagine a way in which one factor might cause another or is the idea ridiculous? For example, did you know that shaving infrequently is associated with a 30% increase in cardiovascular mortality and a 68% increase in stroke incidence in British men? That's a better association than you get with some blood lipid markers and most dietary factors! It turns out:

The one fifth (n = 521, 21.4%) of men who shaved less frequently than daily were shorter, were less likely to be married, had a lower frequency of orgasm, and were more likely to smoke, to have angina, and to work in manual occupations than other men.

So what actually caused the increase in disease incidence? That's where plausibility comes in. I think we can rule out a direct effect of shaving on heart attacks and stroke. The authors agree:

The association between infrequent shaving and all-cause and cardiovascular disease mortality is probably due to confounding by smoking and social factors, but a small hormonal effect may exist. The relation with stroke events remains unexplained by smoking or social factors.

In other words, they don't believe shaving influences heart attack and stroke directly, but none of the factors they measured explain the association. This implies that there are other factors they didn't measure that are the real cause of the increase. This is a critical point! You can't determine the impact of factors you didn't measure! And you can't measure everything. You just measure the factors you think are most likely to be important and hope the data make sense.

This leads us to another important point. Investigators can use math to estimate the relative contribution of different factors to an association. For example, imagine the real cause of the increased stroke incidence in the example above was donut intake, and it just so happens that donut lovers also tend to shave less often. Now imagine the investigators measured donut intake. They can then mathematically adjust the association between shaving and stroke to subtract out the contribution of donuts. If no association remains, then this suggests (but does not prove) that the association between shaving and stroke was entirely due to shaving's association with donuts. But the more math you apply, the further you get from the original data. Complex mathematical manipulation of observational data requires certain assumptions, and while it is useful for extracting more information from the dataset, it should be viewed with caution in my opinion.

Of course, you can't adjust for things you didn't measure, as the study I cited above demonstrates. If factors you didn't measure are influencing your association, you may be left thinking you're looking at a causal relationship when in fact your association is just a proxy for something else. This is a major pitfall when you're doing studies in the diet-health field, because so many lifestyle factors travel together. For example, shaving less travels with being unmarried and smoking more. Judging by the pattern, it also probably associates with lower income, a poorer diet, less frequent doctor visits, and many other potentially negative things.

If the investigators had been dense, they may have decided that shaving frequently actually prevents stroke, simply because none of the other factors they measured could account for the association. Then they would be puzzled when controlled trials show that shaving doesn't actually influence the risk of stroke, and shaving mice doesn't either. They would have to admit at that point that they had been tricked by a spurious association. Or stubbornly cling to their theory and defend it with tortuous logic and by selectively citing the evidence. This happens sometimes.

These are the pitfalls we have to keep in mind when interpreting epidemiology, especially as it pertains to something as complex as the relationship between diet and health. In the next post, I'll get to the meat of my argument: that modern diet-health epidemiology may in some cases be a self-fulfilling prophecy.