Bill Harris, M.D. | Q&A

Tooth Enamel Erosion?
Q&A with Bill Harris, M.D.

Q. I am trying to learn the cause of enamel erosion on my teeth. I am a 43 year old male, always athletic, and always looking for ways to improve my diet and health. So it was disheartening to learn from my dentist at my last 6 months cleaning that I had sudden loss of tooth enamel, and he states that I should have them crowned. My four lower front teeth need crowned, per my dentist. He asked about acid, asking if I had acid reflux, if I was bulemic, if I drank soda, coffee, sucked on limes/lemons, suffered heartburn, etc. My answers were no, no, no. He sent my to my primary care physician, who did blood work, an upper GI test, which both came back fine. I am still scheduled for a 24 hour PH test, with that tube down my esophagus, and wearing a computer to my belt for the test. I saw a second dentist who concurred with my first dentist. I never ate much red meat, gave up red meat about five years ago, gave up fish and chicken about three years ago, gave up milk over 15 years ago, gave up eggs, cheese, etc. over a year ago. Gave up soda pop three years ago. Never have drank coffee. So I have been vegan for over a year. I consider myself to have a normal vegan diet. I chew and swallow a raw garlic clove every night before dinner. I drink a tablespoon of flaxseed oil before dinner. I drink one cup of decaf green tea every morning. I take glucosamine and MSM twice a day, brush once a day with a non fluoride toothpaste, once a day with a fluoride toothpaste. I take a multiple vitamin once a day, approx. 3 grams of vit C a day, 400 IU of vit E, co Q 10, acidophilus. I installed a Culligan water system two years ago, a water softener and a water purifier under the kitchen sink for consumption. I wear a dental bite plate at night and when I lift weights in the gym so that I don't grind my teeth. I could go on, but those are the relative basics, I believe. What could be causing the erosion of the enamel on the inside of my lower teeth? Some of it is occurring to a lesser degree to the inside of my upper front teeth? I would be very grateful for a response! Thank you so much!

A. Dear Tim,

Vitamin C is ascorbic acid. The RDA for C is 60 mg and you are taking 3000 mg/daily, 50 times the RDA. I just now used litmus paper to test the pH of my own saliva and found that it was ~ 6. The surface pH of a moistened vitamin C tablet was 4.5 and my salivary pH dropped to 5.0 when I put the tablet in my mouth. The threshold pH at which point demineralization of the enamel is thought to occur is between 5.5 and 5.7. It might be worth your while to get some litmus paper and perform similar experiments on yourself in relation to your vitamin C intake.

Celiac syndrome and excessive consumption of starches are also related to erosion of the enamel. Starches readily release fermentable sugars and the oral bacterium Streptococcus mutans metabolizes the sugar and releases various organic acids that are the principal cause of childhood caries. If starches are a big part of your vegan diet consider using more fresh vegetables in their place, they have much higher nutrient values.

Most likely your enamel problem is related to oral acidity. Early in my vegan transition (~1964) I consumed 5-6 grapefruit daily but discovered one day that I had given myself permanent transverse ridges in my upper incisors. Citrus fruits leave an alkaline residue when fully metabolized but they are strongly acidic in the mouth. The pH of orange juice is ~ 4.5

Incidentally, Linis Pauling spoke to our UCSF medical school class in 1959 and discussed his belief in the therapeutic virtues of vitamin C. I subsequently dabbled with his ideas but finally decided that the best preventive for the common cold is not megadoses of vitamin C but prompt consumption of fresh citrus when the first cold symptoms appear. While I think a carefully selected daily multivitamin is good nutritional insurance I think that a well balanced vegan diet will provide all essential nutrients without any need for megadoses of vitamins.

Hope this helps.


-William Harris, M.D.


Lingstrom P, van Houte J, Kashket S

Department of Cariology, Institute of Odontology, Goteborg University, Sweden.

Sucrose and starches are the predominant dietary carbohydrates in modern societies. While the causal relationship between sucrose and dental caries development is indisputable, the relationship between food starch and dental caries continues to be debated and is the topic of this review. The current view of dental caries etiology suggests that in-depth evaluation of the starch-caries relationship requires the consideration of several critical cariogenic determinants: (1) the intensity (i.e., the amount and frequency) of exposure of tooth surfaces to both sugars and starches, (2) the bioavailability of the starches, (3) the nature of the microbial flora of dental plaque, (4) the pH-lowering capacity of dental plaque, and (5) the flow rate of saliva. 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. Although food starches do not appear to be particularly caries inducive in the first situation, the possibility cannot be excluded that they contribute significantly to caries activity in modern human populations. The commonly used term "dietary starch content" is misleading, since it represents a large array of single manufactured and processed foods of widely varying composition and potential cariogenicity. Hence, increased focus on the cariogenicity of single starchy foods is warranted. Other aspects of starchy foods consumption, deserving greater attention, include the bioavailability of starches in processed foods, their retentive properties, also in relation to sugars present (starches as co-cariogens), their consumption frequency, the effect of hyposalivation on their cariogenicity, and their impact on root caries. The starch-caries issue is a very complex problem, and much remains uncertain. More focused studies are needed. At present, it appears premature to consider or promote food starches in modern diets as safe for teeth.

Nothing you have listed above rings a bell with me, however I developed permanent transverse ridges in my own upper incisors in my early vegan days by eating 5-6 grapefruit daily. Citrus fruits leave an alkaline residue when fully metabolized but in the mouth they are acidic enough to erode enamel. You didn't mention citrus but perhaps you should consider other acid foods that might be in your diet.

The cause of dental caries


-William Harris, M.D.

William Harris MD received a degree in physics from the University of California Berkeley, where he earned Phi Beta Kappa honors. He received his degree in medicine from the University of California at San Francisco, and received his postgraduate training at San Diego County Hospital. He holds a Medical License in the State of Hawaii. He has been an Emergency Department physican since 1963, and the Director of the Kaiser Permanente Vegan Lifestyle Clinic on Oahu until his retirement in 1998. Dr. Harris is the author of The Scientific Basis of Vegetarianism.

In addition, he was the 1950 Big Ten Trampoline Champion, is an accomplished hangglider and commercial pilot, and at age 70 became a skydiver with 108 jumps to date. Dr. Harris has been vegetarian since 1950, and vegan since 1963.

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